Veterinary Entomology & Protozoology (VPAR 131) Course Outline, DON MARIANO MARCOS MEMORIAL STATE UNIVERSITY PDF

**DON MARIANO MARCOS MEMORIAL STATE UNIVERSITY** ***NORTH LA UNION CAMPUS*** **COLLEGE OF VETERINARY MEDICINE** **VETERINARY ENTOMOLOGY & PROTOZOOLOGY** **(VPAR 131)** **FE M. CAMALIG** **1^ST^ Sem 2020-21** **Course Outline** **In** **VETERINARY ENTOMOLOGY & PROTOZOOLOGY** **(VPAR 131)** **COURSE DESCRIPTION** This course deals with important arthropods and protozoan parasites of domestic animals, their structure, life cycle, pathology, immunology, public health importance, diagnosis control and treatment. **OBJECTIVES** At the end of the course, the student should be able to : 1\. Identify the different external parasites that affect the domestic animals. 2\. Identify the different protozoan parasites of domestic animals. 3\. Recognize the parasites by knowing their morphology, life cycle and other important characteristics. 4\. Develop/create effective treatment, prevention and control strategies against protozoan infection in domestic animals. 5\. Formulate an effective treatment, prevention and control strategies against external parasite infestation in domestic animals. **COURSE REQUIREMENTS** 1. Quizzes 2. Exams ( Mid-term and Final) 3\. Laboratory exercises 4\. Collection of parasites **GRADING SYSTEM** **Passing Score : 70%** ( 60 % lecture and 40 % laboratory) **Mid Term 60% Lecture** (Class Standing -- Exams, quizzes, recitations) **40% Laboratory** (laboratory exercises, class participation) **Final Grade = 60 % Final 40 % Midterm** **COURSE CONTENT** Module 1 Lesson 2 Phylum Arthropoda Lesson 3 Class Insecta Lesson 4 Order Orthoptera Lesson 5 Siphunculata/Anoplura Module 2 Lesson 1 Order Coleoptera Lesson 2 Sub-Order Cyclorrhapa Lesson 3 Sub Family Sarcophaginae Lesson 4 Class Arachnida Lesson 5 Genus Ixodes Module 3 Lesson 1 Sub-Order Mesostigmata Lesson 2 Sub-Order Sarcoptiformes Lesson 3 Class Pentastomida Lesson 4 Protozoa Lesson 5 Class Sarcodina **MODULE 1** Lesson 2 Phylum Arthropoda Lesson 3 Class Insecta Lesson 4 Order Orthoptera Lesson 5 Siphunculata/Anoplura **LESSON 1** **INTRODUCTION TO VETERINARY PARASITOLOGY** This subject is the study of organisms that live in or on another organisms (host) from which they derive nourishment and give no useful return. These organisms are called parasites which can produce harmful effects on the host in the form of diseases. The degree of harm caused by the parasite may vary considerably and may only be evident at certain times, such as when the host is in poor condition or the parasite density is high. Our environmental temperature is favourable for the growth and multiplication of parasites, so therefore a veterinarian should have a sound knowledge of the parasites to understand its nature which could be the basis of its control. **General Divisions**: 1.Veterinary Entomology-study of arthropods 2.Veterinary Protozoology-study of unicellular organisms(protozoa) 3.Veterinary Helminthology-study of worms Veterinary Entomology and Protozoology- 4 units , deals with the causation and transmission of disease by insects, arachnids and other arthropods. Their morphology, biology and pathogenicity of these arthropods and protozoan parasites their treatment and control. **Terminology:** Endoparasites- parasites that live within the host Ectoparasites-parasites that live outside the body of the host Infection-parasitism by an internal parasites Infestation- parasitism by an external parasites Host-living organism that harbors a parasite Parasite-living organism which for the purpose of procuring food and shelter, take up their abode, temporarily or permanently on or within another living organism. **Kinds of Host:** 1.Definitive/Final host-host that harbors the sexual /adult stage of the parasite 2.Intermediate host- host that harbors the asexual/larval stage of the parasite(***first***-harbors the early larval stage of the parasite, ***second***-harbors the larva infective stage) 3.Reservoir host- host other than the animal species that usually harbors the parasite; the host does not show clinical signs ,remains unaffected and serves as a source of infection to other animals. 4.Paratenic host- also known as the transport host, does not exhibit any clinical sign and the parasite does not undergo any further development in the body. **Classification of Parasites:** **A. By kingdom** 1\. Phytoparasite-parasitic to plants 2\. Zooparasite-parasitic to animals **B. By Location** 1.Ectoparasite -- outside the body 2.Endoparasite-inside the body **C. By Nature of Existence** 1.Permanent- spends its entire life cycle(egg to adult) in one host 2.Obligate- parasites that cannot exist without the host 3.Facultative-could be parasitic or free living 4.Temporary-parasitic only during certain stages of life 5.Erratic-found in organs not their normal abode 6.Aberrant-parasites that follow a certain route of migration, reach an organ, become encapsulated and die 7.Spurious-parasite of another animal which passes through the body of an animal without further development or without causing any damage or injury, it results from coprophagy 8.Hyperparasite-parasite which is parasitic on another parasite **D. According to Host** 1.Monoxenous- requires one host to complete its life cycle 2.Heteroxenous-requires 2 or more host to complete its life cycle 3.Stenoxenous-has a narrow range of final host 4.Euryxenous-affects a wide range of hosts **E. By Predilection Site** 1.Hematozoic-lives inside the blood cells 2.Cytozoic-lives inside the body cavity 3.Enterozoic-lives in the lumen of small intestine **F. By Time and Frequency of Occurrence in the host** 1.Periodic -- one which in its larval stage, develops in host different from that of the adult 2.Transitory- one which passes the larval period of development within the body of the host while the adult becomes free-living afterwards 3.Accidental/incidental-occurs occasionally on host in which they are not usually found and cause considerable harm **G. Others** 1.Pathogenic-causes injury to host 2.Non pathogenic- does not cause injury to host **Animal Association**: 1.Parasitism-one party is benefitted while the other is harmed Parasitosis-host manifest clinical signs Parasitiasis-host does not show clinical signs Parasitiadism-the parasite lays egg on the host 2.Commensalism-one party is benefitted, the other is unharmed 3.Symbiosis-the association is necessary for both, both are benefitted 4.Mutualism-similar to symbiosis but the association is not so essential and the host can get along well even without the parasite 5.Predation-killing of the host by the parasite for survival 6.Phoresy-temporary relationship, usually with no metabolic dependence in which one organism transport or shelters another **Effects of Parasites on host:** 1.They suck blood (mosquitoes, hookworm), lymph (midges) or exudates (lungworm) 2.Feed on solid tissues either directly (liverfluke, kidney worm) or after liquefying it (chiggers) 3.Compete with the host for food by ingesting intestinal contents(ascarids) or by absorbing them through the body wall (tapeworms) 4.Causes mechanical obstruction of the intestines (ascarids), bileducts (fasciola), blood vessel (heart worm),lymph channels(Wucheraria), bronchi (lungworm) 5\. Causes pressure atrophy (hydatid cyst) 6.Destroy host cells by growing in them (coccidian) 7.Produce various toxic substances such as hemolysin, histolysin and anticoagulants 8.Causes allergic reactions 9.Cause various host reactions such as inflammation, hypertrophy, hyperplasia and nodule formation 10.Stimulate the development of cancer (Spirocerca lupi) 11.Carry diseases and parasites 12.Reduce their host resistance to other diseases and parasites 13.Loss or reduction of aesthetic value **REVIEW QUESTIONS (40%)** 1. Identify the different divisions of parasitology. (10%) 2. Define veterinary parasitology (5%) 3. Differentiate polypod larva to apodous larva (10%) 4. Enumerate the effects of parasites on the host.(15%) **LESSON 2** **PHYLUM ARTHROPODA** Arthropoda derived from greek word arthros -- a joint and podos- feet. Largest phylum in the animal kingdom (80% of the known animal species).Their major characteristics are a hard chitinous exoskeleton, asegmented body and jointed limbs.The hard exoskeleton of arthropod is secreted by an underlying epidermis and consist of numerous segments.The general characteristics are metamerically segmented- body is divided into 3 segments (head, thorax, abdomen) and bilateral symmetry- appendages are always paired **[General Structure and Function]** **I. Integument** Chitin is outer covering of arthropods, modified into: a.) stomodeum-anterior part of the alimentary canal b.) proctodeum-posterior part of the alimentary canal Sclerite- typical body segments formed by chitinous plates, divided into: a.) tergum- dorsal sclerite b.) sternum-ventral sclerite c.) pleuron-lateral sclerite **II. Circulation** The body cavity is not a coelom but a hemocoele which is a space full of blood which bathes all organs of the body. The system is composed of: a.) enlarged dorsal blood vessel (heart) b.) pericardium (encloses the heart) c.) paired ostia (opening in the pericardial walls) d.) short arteries **III. Respiration** The arthropod may possess any or 2 of these structures: a.) gills (bronchiae)-found in larva, nymph and adult aquatic species of various kinds b.) tracheae- fine elastic tubes in the chitinous lining which branches and ramifies among the internal organs c.) lung book -- found in spiders d.) gill book- found in crabs e.) spiracles-small circular opening in the exoskeleton f.) stigmata-external opening in the internal organs **IV. Digestion** 1\. foregut or stomodeum- buccal cavity, pharynx, proventiculus, gizzard, involved in ingestion, passage and disintegration of food particles 2.midgut or mesenteron- storage of food and enzyme secretion 3.hindgut or proctodeum- absorption of food and expulsion of fecal materials **V. Excretion** 1\. paired nephridia -- crustacean 2\. malphigian tubules- insects 3\. coxal glands- this together with malphigian tubules are present in class arachnida **VI. Nervous System** 1\. supraesophageal center (Brain) 2\. ganglionated ventral nerve cord **VII. Reproduction** Male- paired testes, vas deferens, paired seminal vesicle, penile organ Female- paired ovaries, oviduct, uterus, vagina, spermatheca (sperm receptacle) **CLASSES** **A. Insecta-**largest group, adults with 3 pairs of legs,3 main parts of the body (head, thorax, abdomen) Orders: 1.) Phthiraptera (lice) 2.) Orthoptera (cockroaches) 3.) Hemiptera (Bugs) 4.)Coleoptera (beetles) 5.)Siphonaptera (fleas) 6.)Diptera (2-winged flies) **B. Arachnida-** adults with 4 pairs of legs, 2 piece of mouth parts ,without antennae and wings, include king crabs, scorpions, spiders, ticks and mites and their relatives Order: Acarina (ticks and mites) **C. Crustacea**- main body divisions are cephalo-thorax and abdomen, legs are found on thoracic and abdominal segments, include crayfishes, shrimps ,lobsters, crabs, wood lice and their relatives, most of them are aquatic and breathe by means of gills **D. Myriapoda**- includes; a**) Diplopoda**- a pair of antennae, elongated and cylindrical body, numerous segments; each bearing 2 pairs of legs (e.g. millipede), b.) **Chilopoda**- long narrow dorso-ventrally flattened, body with several segments; each bearing a pair of jointed legs (e.g. centipedes) **E. Pentastomida**- adults without legs except 2 pairs of hooks near the mouth , larvae with 2 pairs of legs ,includes tongueworm (Linguatula serrata) **General Information** **Types of Development**: 1\. Direct/incomplete metamorphosis- one or two of the stages are missing with the exception of the adult; hatched insect is a miniature of the adult 2\. Indirect/complete metamorphosis- characterized by having the four stages ; egg, larva, pupa, adult. The hatched insect differs morphologically from parent. **Stages in the Life Cycle of an Arthropod**: 1\. egg- stage that undergoes a series of segmentation 2\. larva- developing form after it has emerged from the egg and before it is transformed to pupa; it is the feeding stage of the parasite 3.pupa- the quiescent stage of metamorphosis that emerge from the larval stage 4\. nymph --form that leaves the egg with similarity in morphology with the adult 5\. adult-the reproductive stage of the parasite **Types of larva**: 1.polypod- larva with a well- marked head, a 3 segmented thorax with legs, a 10-segmented abdomen and pairs of abdominal legs (prolegs) or fleshy hooked legs. (e.g. caterpillar) 2.oligopod- larva with a well- marked head, 3 pairs of thoracic legs but no abdominal legs (e.g. beetles) 3\. apodous- larva with no legs on the thorax and abdomen (e.g. maggots) **Types of Pupa:** 1\. free or exarate-the wings and legs are free from the body, hence can be seen externally (e.g. beetles) 2\. obtectate- pupa with legs and wings bound to the body by moulting fluid but still visible externally (e.g. mosquitoes) 3\. coarctate-last larval skin retained, this hardened skin (puparium) encloses the pupa, hence it cannot be seen externally **Types of Female:** 1\. oviparous- female that lays egg 2\. larviparous- female that lays live larva 3\. pupiparous- female that lays larva that immediately turns into pupa **Modes of Transmission:** 1\. Mechanical a.) direct-hitch hiking in legs or mouthparts (does not undergo development in insect's body) b.) transmission by biting 2\. Biological a.) propagative-undergoes multiplication and the insect serves as culture medium b.) cyclopropagative-develop and multiply in insect's body c.) cyclodevelopment-undergoes development but there is no multiplication 3\. Transovarial-organism is transmitted by succeeding generation of ticks but there is no multiplication 4\. Transtadial-organism is transmitted by the next developmental stage of ticks **REVIEW QUESTIONS (40%)** 1. Discuss the life cycle of an arthropod (10%) 2. Differentiate complete metamorphosis from incomplete metamorphosis(10%) 3. Discuss exretion in arthropods (10%) 4. Define: Monoxenous, spurious, erratic, pathogenic and symbiosis (10%) **LESSON 3** **CLASS INSECTA** There are two major classes of arthropods of veterinary importance, namely the Insecta and Arachnida. The two major classes can be differentiated by the following general characteristics. Class insecta have 3 pairs of legs, the head, thorax and abdomen are distinct and they have a sigle pair of antennae. While the arachnids have 4 pairs of legs, the body is divided into a cephalo-thorax and abdomen and there are no antennae. Mostly of veterinary importance, comprise 70% of the known species of arthropods **GeneralCharacteristics:** **1**. **Head** **-** is ovoid or globular capsule, composed of a number of plates or sclerites at the anterior end of the body **-**generally comprises six fused segments **-**eyes are usually present and placed laterally above the cheeks or genae, eyes meet on the midline (**holoptic**) or eyes that are wide apart (**dichoptic**) **-**parts are**: frons** (unpaired upper facial part),**clypeu**s (lies immediately anterior to the frons), **labrum** (unpaired sclerite),**epicranium** (upper region of the head from the frons to the neck), **gena** (also known as the cheek) and **vertex** ( part of the epicranium which lies immediately behind the frons). **-**types of insect head depending on the inclination of the long axis and the position of the mouthparts: a.)hypognathous -long axis is vertical, mouthparts ventral b.)prognathous -long axis is horizontal or slightly inclined ventrally mouthparts anterior c.)opisthognathous- head directed backwards so that the specialized mouthparts arise between the anterior legs -type according to exposure of mouthparts: a.)ectognathous- mouthparts exposed externally b.)endognathous- mouthparts unexposed externally **2**. **Antennae** \- situated in between or in front of the compound eye, some are elongated and many segments (mosquitoes) some are short and squat (housefly) -a pair of very motile jointed appendage which are articulated with the head in front of or between the eyes, and in action are directed forwards -divisions: a.) **scape** (first or basal segment; longest), b.) **pedicel** and c.) **flagellum** (forms the remainder of the antennae, it varies greatly in form among different families in adaptation to environment. **3**. **Mouthparts** -great variation in the structure depending on feeding habits with adaptations for: **chewing, sponging or piercing, sucking** -basic elements are**: upper lip (labrum), lower lip (labium)** -between these structures are 2 pairs of biting jaws: **upper pair (maxillae), lower pair (mandible**), they have areas or surfaces adopted for: **cutting, slashing and grinding** -underside the labrum is a small membranous structure; the **epipharynx** (which bear the organ of taste) -another membranous structure; the **hypopharynx** (which bears the opening of the salivary duct) -maxillae and labrum posses jointed **palps** which are sensory in function. -mandible is adapted for cutting or crushing the food and frequently also for defence -maxilla holds the food when the mandible is extended, as well as assisting in mastication **Kinds of feeding habits:** a.) mandibulate or biting- Orthoptera, Diptera b.) piercing and sectorial- Hemiptera, Siphunculata, Siphonaptera, Diptera c.) haustellate mouthparts adapted for taking up liquid without piercing- Lepidoptera, some Diptera and Hymenoptera d.)greatly reduced or non functional-Ephemeroptera and certain Lepidoptera **4.Cervix or Neck Region** **-**flexible region between the head and prothorax. It its membrane are embedded a variable number of cervical sclerites. These occur in nearly all order of insects but are best developed in the more primitive groups **5**. **Thorax** **-**consist of 3 segments **: prothorax, mesothorax and metathorax** **-**they are fused, each segments bears legs -mesothorax and metathorax typically bears a pair of wings and legs **6. Legs** **-**-consist of **coxa, trochanter, femur, tibia and tarsus** **-**coxa is the functional base of the leg, the delimited posterior lobe is called **meron** **-**trochanter is the second segment , articulates with the coxae but rigidly fixed with the femur -femur is the largest region of the leg, conspicuous in jumping insects -tibia slender and often equals or exceed the femur in length, carries one or more tibial spurs -tarsus consist primarily of a single segment but more usually it is divided into sub-segments typically in number **Leg Movements and Locomotion** a.) walking (or running) -- most widespread form of terrestrial locomotion during which the forelegs serve as organs of traction and the mid-legs are supporting structures while the hind-legs exert a propulsive force b.)jumping mechanism- vary from one group to another c.) swimming- occur in several groups of aquatic insects d.) unique physical mechanism- occurs in soft bodied insect larvae. The musculature of the body walls play an important role and the haemocoele acts as a hydrostatic skeleton **7. Wings** -normally 2 pairs but in Diptera, the posterior pair is reduced to a pair of **balancers** or **halters** **-**the presence of wings is one of the most characteristic feature of insects and their dominance may be attributed to the possession of this organ. A typical insect wing is a thin, transparent membrane, compose of closely adherent upper and lower layer which enclose a series of longitudinal strengthening tubes, the **vein**. Each vein contains a trachea or breathing tube and an extension of the blood containing haemocoele. The characteristic arrangement of wing vein is called **wing venation.** This is a useful basis for identification -margins of insect wing: a.) anterior margin or costa (ab), b.) outer or apical (bc), c.) inner or anal (cd) -the structure found in Dipterans which replace the reduced posterior wing is called **balancer or haltere** **-insect flight**- the aerodynamic theory of insect flight is complicated and not fully developed. Normal flight depends on the creation by a propeller like action of the wings of a zone of low pressure in front of and above the insect and one of high pressure behind and below it, the consequent movement being resultant of the thrust provided by the insect and forces due to gravity and air resistance. Before flight can occur the thoracic flight muscles must attain a sufficiently high temperature and for this reason some insects carry out preliminary vibrations of the wings before flight thereby raising the temperature. **8. Abdomen** -clearly segmented, soft and membranous, structures may be present such as: **copulatory claspers, ovipositor, external genetalia** -composed of a series of segments which are more equally developed than in the other regions of the body. It is primitively 11 segmented -appendages and processes of the abdomen (gills, cerci) -external genetalia: a) male (pair of **claspers** that grips the female during copulation**, aedeagus** lies between claspers composed of penis and parameres which is a pair of more lateral structures b.) female (ovipositor or egg laying organ consist of 3 pairs of valves **9. Respiratory** -consist of **tracheae,** the finest branches being termed tracheoles.In many winged insects the trachea are dilated in various parts of the body to formed thin walled vesicles or **air sacs**. The air generally enters the trachea through paired usually lateral openings termed **spiracles** which are segmentally arranged along the thorax and abdomen. More rarely the spiracles are closed or wanting, respiration in such cases are cutaneous. In the immature stages of many insects (aquatic) special respiratory organs known as gills or branchiae are present, and these may or may not co-exist with open spiracles **Physiology of Respiration** A tracheate insects and those stages of the life cycle during which the tracheal system is filled with liquid obtained their oxygen by direct diffusion from the environment into the body fluids. When a functional tracheal system is present, however the carriage of oxygen to the tissues requires that the gas a.) enter the tracheal system b.) transported to its finest branches c.) passes from them into the cells concerned. **10. Alimentary canal** -the alimentary canal is a tube of very variable length; in some cases it is about equal to that of the body, while in others it is much longer and convoluted -**Regions of the alimentary canal**: -**1 Fore gut**- anterior ectodermal invagination, subdivisions: a.) preoral food cavity- not strictly a part of the gut b.) pharynx- region between mouth and esophagus c.) esophagus- simple, straight tube passing from the hinder region of the head into the fore part of the thorax d.) crop- dilation of the esophagus, function mainly as food reservoir, though digestion occurs when its contents are mixed with salivary enzymes and some lipids maybe absorbed there. e.)gizzard- with prominent denticles and possess a cardiac or esophageal valve that prevents regurgitation **2. Mid Gut**- also termed the stomach or venticulus, may be sac like, coiled and tubular, or divided into 2 or more well-defined regions. It is involved in the storage and digestion of ingested food by the action of enzymes which are secreted by the epithelial cells of the gut. **3. Hind Gut-** composed of the ff: ileum, colon, rectum- which contain papillae which absorbs nutrients and water **11.Circulatory system** -among insects the circulatory system is usually open, with only a single closed dorsal vessel. The organs and tissues belonging to the circulatory system are the ff: -1. Diaphragms and sinuses -2. Dorsal vessel- comprises 2 regions: heart or pumping organ and aorta the conducting vessel -3. Accessory pulsatory organs -4. Blood- the blood or haemolymph of the insects is contained in the body cavity, where it bathes the various internal organs and also enters the appendages and the tubular cavities of the veins in the wing. It is the only extracellular fluid in the insect body and makes up 15-75 % of the volume of the insect, the amount and composition varying with the species and its physiological condition. It consist of the liquid **plasma** and numerous blood cells or hemocytes. -functions of plasma: 1.) storage of water on which the tissues can draw during dessication, 2) organ of food storage, 3) transport food materials and homones, 4) exerts a mechanical function in the eversion of protrusible structures such as penis of male insects and 5) dilation of the wings at the emergence of the adult -functions of hemocytes- 1) phagocytosis, 2) protection and 3) food storage **12. Nervous system** **-**forms an elaborate connecting link between the sense organs which response to various external and internal stimuli and effector organs such as muscles, glands and luminous structures, through which the insect reacts to the stimuli by coordinated behavioural changes -**Three general divisions:** -1.Central nervous system- (brain or supraesophageal center, subesophageal ganglia and ventral nerve cord) -2.The visceral or sympathetic nervous system- (esophageal sympathetic or stomogastric nervous system, ventral sympathetic nervous system, caudal sympathetic nervous system) -3.The peripheral nervous system- supplies the integument **13. Reproductive system** -male (2 testes, vas deferens, seminal vesicle, penis with a sheath, other accessory structures (pair of claspers which grips the female during copulation) -female (2 ovaries, receptaculum seminis, ovipositor or egg laying organ, consist of 3 pairs of valves)) **14. Excretory system** **-**the function of an excretory system is the maintenece of a relatively constant internal environment for the tissues of the body; among the regulatory processes involved are the elimination of the nitrogenous waste products of protein breakdown and the control of the ionic composition of the hemolymph. The excretory organs are: 1) malphigian tubules, 2) nephrocytes, 3) fat-body and 4)cephalic glands. Malphigian tubules is the only organ with a recognized specific function. **15. Sense Organs and perception** **-**the sense organs or receptors are those structures whereby the energy of a stimulus arising outside or less obviously within the insect, is transformed into a nervous impulse which after transmission to one of the central ganglia, usually results in a change in the behaviour of the insect or in the maintenance of some existing activity. -Types of sense organs: 1.) mechanoreceptors- excited by processes involving the mechanical deformation of some part of the receptor (touch, air pressure) 2.)auditory organs- sound regarded as air disturbances 3.)chemoreceptors- excited by the presence of chemical substances secreted by other insects a.) gustatory sense (taste), b.) olfactory senses (smell) 4.)temperature receptors-radiation, convection or conduction may stimulate insect's behaviour 5.)humidity receptors 6.)vision and visual organs- responses to light are mediated by: a) dermal light sense , b) dorsal ocelli, c) lateral ocelli (stemmata) the only eyes present and d.) compound eyes- aggregates of separate visual elements **16. Development** \- eggs consist of large mass of yolk surrounded by cytoplasm and undergo segmentation and body of embryo is formed around the yolk. -Kinds of metamorphosis: -1. Complete or direct- undergoes these stages Egg\-\-\-\--larva (feeds)\-\-\-\-\--pupa (quiescent phase)\-\-\-\-- imago(young adult)\-\-\-\--adult -the rate of development is influenced by: temperature and fair amount of moisture -2. Incomplete or direct Egg\-\-\-\--nymph or larva\-\-\-\-\--imago **Stadi**a- phase which separates different stages of ecdyses **Instar-**form of insect during each stadium, during each development, the insect undergoes a various degree of metamorphosis **REVIEW QUESTIONS (40%)** 1. Differentiate hypognathus to ectognathous (10%) 2. Discuss the insect flight (10%) 3. Discuss the physiology of respiration (10%) 4. Enumerate the different systems of parasites and give their functions (10%) **LESSON 4** **ORDER ORTHOPTERA** **(Cockroaches)** Cockroaches or roaches are n ancient group, with ancestors originating during the Carboniferous period. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as pests. Cockroaches are somewhat generalized insects lacking special adaptations (such as the sucking mouthparts of aphids and other true bugs);they have chewing mouthparts and are likely among the most primitive of living Neopteran insects. They are common and hardy insects capable of tolerating a wide range of climates, from Arctic cold to tropical heat. Tropical cockroaches are often much larger than temperate species.Some species, such as the gregarious German cockroach, have an elaborate social structure involving common sheleter, social dependence, information transfer and kin recognition. Cockroaches are abundant throughout the world and live in wide range of environments. They occupy a wide range of habitats. May live in leaf litter, among the stems of matted vegetation, in rotting wood, in holes, in stumps, in cavities under bark, under log piles and among debris. Some live in arid regions and have developed mechanisms to survive without access to water sources. Others are aquatic, living near the surface of water bodies. Characteristics Species of this order have 2 pairs of wings - The anterior pair or mesothoracic pair is thickened act as covers (called tegmina) while the posterior pair or metathoracic pair is membranous. - The antennae are usually long and filamentous and many jointed - The mouth parts are adapted for chewing - They are dorsoventrally flattened - Examples : grasshoppers, crickets, locusts and cockroaches Cockroaches 1. Blatella germanica -- "croton bug or German roach" adult measures 15 mm length the colour is light brown with 2 longitudinal stripes over the prothorax and wings. Wings are present in both sexes. 2. Blatta orientalis- "oriental roach" about 25 mm long, dark brown in colour, the wings do not quite reach the tip of the abdomen of males, females does not have wings 3. Periplaneta Americana --"American roach" , with well developed wings in both sexes, large reddish brown in colour ( most common) Habits: Life Cycle: 10-12 days after fertilization\-\-\-\--eggs are laid in egg cases/capsules which are deposited in crevices\-\-\-\-\-\--development is dependent on temperature and food supply available\-\-\--larva( white in colour, then turns to brown as it matures \-\-\-\-\-\-\--6 moults\-\-\-\--nymph\-\-\-\-\--1 moult\-\-\-\-\-\-\--adult Average length of complete life cycle: B. orientalis -- 12 days B. germanica -- 2-3 days P. Americana -- 21 days Pathogenecity: 1. Not parasitic, it is a household pest 2. Omnivorous habits causes damage to materials 3. Leaves a "roachy odour" from gland secretions that spoils food with which it comes in contact with 4. Act as intermediate hosts of nematodes (gizzard, proventicular and eye worm of poultry) and cestodes (Hymenolepis diminuta or rat tapeworm) 5. Mechanical transmitter of fungi, bacteria and protozoan cysts Control: The control is very difficult because they breed rapidly Most effective control is the use of insecticide (e.g. chlorinated hydrocarbons: dieldrin or lindane) and cleanliness Stadia-different stages separated by ecdyses, the form of insect during its stadium is called instar Diagnosis- the art of distinguishing one disease from another, the determination of the nature of a case of disease **ORDER HEMIPTERA** **(Bugs)** General Characteristics: 1. Blood sucking 2. Temporary parasites of birds and mammals 3. Nocturnal feeders 4. (-) phototactic 5. Positively (+) thigmotactic 6. Responds to odour and warmth 7. The mouth parts are adapted for piercing and sucking 8. Two pairs of wings are usually present, the anterior pair often of harder consistency (hemelytra) and the posterior pair is membranous Important Families: Cimicidae (bedbugs) Reduviidae (assassin/cone-nosed/kissing bugs) **Family Cimicidae** **Genus Cimex** Species: Cimex lectularius (common bedbugs) Cimex hemipterus (oriental bed bugs) Morphology: 1. Small and flat-bodied 2. Elongate oval in shape 3. Yellowish brown in colour 4. Wings are vestigial 5. Adult has ventral thoracic stink glands which is responsible for the characteristic odour of the insect and act as alarm pheromones Life Cycle and Habits: Lays 150-200 eggs (creamy white with operculum)\-\-\-- 3 to 14 days at 23 degrees centigrade\-\-\-- larva\-\-\-\-\-\-\--undergo 5 nymphal stages (depends on food supply and tempt\-\-\-\-\--8 to 13 weeks\-\-\-\-- adult - The bugs live long and can survive long periods of starvation. - They live in crevices and cracks of wood near the sleeping places of their hosts - They are nocturnal insects but will bite in the daytime if the hosts are quiet - After a blood meal the bug defaecates and usually turns around in such a way that its faeces fall on or near the wound, thus providing the possibility of transmission of diseases through faeces. Causes; 1. Very annoying insects in human dwellings 1. Causes irritation 2. Anemia in poultry Control: 1. Chlordane 2. Dieldrin Pathogenesis: 1. Annoyance 2. Debilitating to humans and animals whose sleep is disturbed at night 3. Inconclusive evidence of transmitting Hepatitis B virus **Family Reduviidae** Subfamily : Triatominae Genus: Triatoma Species: Triatoma sanguisuga (Mexican bed bug) T.protracta (chinese bed bug) Morphology: 1. Large, less flat bodied 2. Elongate in shape 3. With well developed"half-wing" (a leathery proximal half called hemelytral pads and a distal half which is membranous) 4. Dark brown in colour 5. Bite is less painful than bedbugs Pathogenesis: Vector of Chagas diseases (Trypanosoma cruzi) **LICE** **General Characteristics:** 1. Dorsoventrally flattened 2. Wingless 3. Most are blind but a few have primitive eyes which are merely photosensitive spots 4. Legs terminate in claws (the lice of mammals having one claw on each leg while in birds possess two) 5. Permanently ectoparasitic most being unable to survive away from the host for more than a day or two 2. **Orders:** **Mallophaga (Biting lice)** **Siphunculata or Anoplura (Sucking lice)** **ORDER: MALLOPHAGA** **(Biting lice)** - Parasites of birds and less frequently in mammals Gen. chac : 1. Small, wingless, and have dorsoventrally flattened bodies 2. With vestigial eyes 3. Antennae have 3-5 segments 4. With indistinctly segmented thorax -- mesothorax and metathorax are fused 5. Claws are small Habits: 1. Mounthparts are adapted for biting and chewing 2. Feeds on cuticular material, hair, feather and epidermal scales, exudates and many others 3. Highly host and site-specific Suborder : Amblycera Ischnocera **Suborder: Amblycera** Morphologic characteristics: 1. Antennae not readily seen because it lies on the groove on the sides of the head 2. Maxillary palps may be present 3. Mandibles bite horizontally Important species: A. Birds 1. Menacanthus stramineus "Yellow body louse" Host : Fowls, turkey, peacock Site: Attacks areas of the skin which are not densely feathered like breast, thigh and around Morphology : abdominal segment have bristles; eggs are laid in clusters in the feathers near the skin and the nymphs look much like adults 2. Menopon gallinae 3. Trinoton anserinum 4. Holomenopon leucoxanthum- causes " wet feathers" in ducks B. Mammals 1. Heterodoxus spiniger -- of low prevalence in dogs 2. Gyropus ovalis- occurs in rodents and guinea pigs 3. Gliricola porcelli -- occurs in rodents and guinea pigs 4. Trimenopon hispidum- occurs in guinea pigs **Sub-Order: ISCHNOCERA** Morphologic Characteristics: 1. Antennae are filiform and visible at the sides of the head 2. Maxillary palps are absent 3. Mandibles bite vertically 4. Broader than Amblycera Important Species: A. Birds 1. Cuclutogaster heterographus- "head louse" 2. Lipeurus caponis- 'wing louse" 3. Goniocotes gallinae- "fluff louse" 4. Goniodes gigas- " large body louse" 5. Chelopistes meleagridis -- "common turkey louse" 6. Columbicola columbae -- "slender pigeon louse" 7. Anaticola crassicornis and Anaticola anseris- ducks and geese B. Mammals 1. Damalinia bovis -- "biting louse of cattle 2. Damalinia equi-"biting louse of horses" 3. Damalinia ovis -- "sheep louse" 4. D. caprae -- goats 5. D. limbata- goats 6. D. painei -- goats 7. Trichodectes canis -- "biting louse of dogs" Pathogenic effects: 1. Restlessness and the animal becomes unable to sleep resulting to a decrease in production 2. Injury on the areas of the body attacked by the lice 3. Stomach hair- ball formation in ruminants due to excessive licking General Life Cycle of Lice: Lice of the two suborders have very similar life cycles. During a life span of about a month the female lays 200-300 operculate eggs (nits). These are usually whitish and are glued to the hair or feathers where they may be seen with the naked eye. There is no true metamorphosis and from the egg hatches the nymph, similar to, though much smaller than the adult. After three moults the fully grown adult is present. The whole cycle from egg to adult takes 2-3 weeks. Some genera are capable of rapid population expansion by changing to asexual reproduction by parthenogenesis. The most notable example in domestic stock being Damalinia. **REVIEW QUESTIONS (40%)** 1. Discuss the pathogenic effects of Order Orthoptera (10%) 2. Discuss the morphological characteristics of Order Hemiptera (10%) 3. Discuss the Life cycle of lice, differentiate biting from sucking lice(10%) 4. Create an effective control system for lice infestation in domestic animals (10%) **LESSON 5** **ORDER SIPHUNCULATA/ANOPLURA** **(Sucking Lice)** The lice are superbly adapted and highly successful insect ectoparasites of birds and mammals. Most species of mammals and birds are infested by at least one species of louse, excluding monotremes and bats. In complete contrast to most fleas or ticks, lice spend their entire lives on the host and are highly host specific. Many species even preferring specific anatomical areas. The sucking lice are usually large, up to 5mm, with small, pointed heads and terminal mouthparts. They are generally slow moving and have powerful legs each with a single large claw. They occur exclusively on mammals. Characteristics 1. They are sucking lice 2. Wingless insects living as ectoparasites on mammals 3. The mouthparts are adapted for sucking the tissue fluids and the blood of the host. A mouth cone or haustellum is present which is a pouch within the head where the sucked blood is contained 4. The two antennae are visible at the sides of the head and composed of 5 segments 5. The thorax is small and the 3 segments are fused together 6. The abdomen is large with 7 of its 9 segments are visible, on its sides are dark brown areas of thickened chitin called "**paratergal plates**" 7. The eyes are reduced or absent, present in Pediculus humanus (headlouse) 8. The first pair of legs is usually smaller with weaker claws, the third pair is usually the longest, possess only 1 claw by which the hair of the host is held between the **tibial spur**, a thumb like process of the tibia. In Hematopinidae, the hold in the hair is aided by a **spiny pad**, the **tibial pad** which can be thrust up to lock the grip on the hair 9. The head is more or less pointed anteriorly 10. No sexual dimorphism General Habits: 1. Slow moving but have a powerful leg 2. Occur exclusively in mammals 3. Attach their eggs individually to the hairs of the host or in the case of Human body louse, to the fibers of the host clothing 4. With 3 nymphal stages living and feeding in the same way as the adult. All stages feed on blood and maintain contact with their host by a number of relatively simple responses 5. Pediculus and Haematopinus spp. Respond to warmth and smell 6. They are thigmotactic- move less in rough surfaces 7. They are negatively phototactic- move toward dark objects 8. Being ectoparasitic to warm blooded animals, they live at a relatively high temperature, but leave the host at too high temperature as in fever and transfer to another host Life Cycle: 12 days 12 days Egg\-\-\-\-\-- 1^st^ nymph \-\-\-\-\--2^nd^ nymph\-\-\-\-\-\--3^rd^ nymph\-\-\-\-\-\--adult (will reach sexual maturity in one to 3 days ) Families: 1. Family Hematopinidae 2. Family Linognathidae 3. Family Pediculidae **Family Hematopinidae** Characteristics: 1. Yellow or greyish brown in colour 2. Head has forward prolongations (**temporal angles**) behind the antennae 3. The thorax is broad 4. With marked paratergal plates 5. Legs have similar sizes 6. There is a sclerotized plate at the base of the tarsal segment called **pretarsal sclerite** 7. Possess a dark stripe on the sides of the body 8. With one row of spines on each abdominal segment Genus: Hematopinus- "short nosed louse" largest louse of domestic animals (0.6 cm) Species: 1. Hematopinus tuberculatus- occurs in buffalo in Asia and pacific 2. Hematopinus asini -- "sucking lice of equines" found in the roots of mane, forelock and above the hooves 3. H. buffali- buffaloes in South Africa 4. H. suis- "pig louse" largest Anopluran found in domestic animals, found in the neck, jowl and around the ears 5. H. eurysternus- "short nosed cattle louse" 6. H. quadripertusus- occurs in cattle and buffalo in Asia and Pacific **Family Linognathidae** Characteristics: 1. Eyes are absent 2. Bluish black in colour 3. Absent or weakly developed thoracic sternal plates 4. Abdomen is membranous with numerous hairs on segments 5. The third leg pair is larger than the first Genus : 1. Linognathus ovillus-"blue louse or body louse of sheep" 2. L. vituli -- long nosed cattle louse 3. L. africanus -- African blue louse, sucking louse of sheep and goats 4. L. stenopsis-goats, resembles L. africanus but the lateral margins of the posterior antennal regions are slightly convex 5. L. setosus- "canine sucking louse" occurs in dogs and foxes 6. L. pedalis" foot louse of sheep" occurs in the lower parts of the body which are hairy/wooly like feet, belly and scrotum **Family Pediculidae** Characteristics: 1. With pigmented eyes 2. With sclerotized sternal plates on thorax 3. Abdomen has paratergal plates 4. With lobed abdominal margins 5. Legs are similar in size Habits: A. **Crab Louse** 1. Changes position infrequently and moves only for a short distance 2. Dies in two days if separated from the host B. **Body and Head Louse** 1. Moves fairly rapidly and pass from host to host during contact 2. Can survive for 10 days outside the host if well nourished Genus: Pediculus Species: 1. Pediculus humanus humanus/corporis- "human body louse", found in fibers of clothing and the hairs of the chest and axilla 2. Pediculus humanus capitis- "human head louse" found in the hairs particularly on the back of the head Genus: Phthirus Species 1. Phthirus pubis --" human pubic louse or crab louse", found in the pubic hair, may spread to the hairs of the chest, axilla, beard and eyelashes **Effects of Lice on their hosts** Chief effect of lice is irritation 1. Irritation 2. Host become restless and do not feed or sleep well 3. They may injure themselves or damage their feathers, hair or wool by biting and scratching the parts of their bodies irritated by lice. 4. Decrease egg and milk production 5. Excessive licking by calves may lead to the formation of hair balls in the stomach 6. Foot louse of sheep found in the dew claw causes lameness 7. In laboratory animals heavy infection is fatal Pathogenesis: 1. Man a. Cause considerable irritation and scratching which disturbs the person"s rest b. Cutaneous lesions which may vary from papules to pustules due to secondary bacterial infection; ulceration may also be present c. The body louse is a vector of Epidemic typhus (Rickettsia prowazeki), Trench fever (Rickettsia quintana), Relapsing fever (Borrelia recurrentis),Plague (Yersinia/Pasteurella pestis) and Poliomyelitis virus 2. Cattle a. Mild chronic dermatitis (well tolerated) b. Serious anemia and loss of weight 3. Sheep a. Attractant for blowflies b. Slight anemia c. Certain degrees of lameness in foot louse infestation once the skin becomes broken and secondary bacterial infection had taken place d. Reduced wool value 4. Swine a. Reduction of hide value b. Vector of African Swine Fever (Eperythrozoon suis) and Swine Pox virus 5. Horse a. Skin value 6. Dog a. Anemia b. Skin excoriation from scratching Control and Treatment: Poultry ; 1. Dusts or spray of carbaryl or coumaphos 2. Painting of perches with a strong extract of tobacco or nicotine Cattle: 1. Spraying of insecticides- malathion, runnel, coumaphos Sheep: 1.Plunge dipping with insecticides 2\. Spray with insecticides Pigs/Horses -- spray Dogs -- spray and dip Lice infestation in man requires good plane of nutrition an regular hygienic measures Ectoparasiticides (Insecticides/Acaricides) Three main chemical groupings that have been used as the basis for the common ectoparasiticides: 1. Organochlorines 2. Organophosphate 3. Synthetic y pyrethroids- carbamates (poultry), avermectin Methods of Application A. Farm animals 1. Dusts 2. Spray 3. Washes 4. Dips 5. Bait (to trap insects) 6. Pour- on, spot-on or spray-on 7. Ear tags, collars and leg and tail bands- to control fly 8. Parenteral B. Companion or Pet Animals 1. Dusting powders 2. Aerosols 3. Washes/shampoos 4. Insecticidal collars 5. Oral preparations- for demodectic mange 6. Spot --on C. Poultry 3. Dusts (Dieldrin) **ORDER SIPHONAPTERA** **(Fleas)** Characteristics 1. Fleas 2. Wingless insect with laterally compressed bodies about 1.5- 4 mm long 3. The chitinous glossy covering is thick and dark brown 4. Compound eyes are absent, but some have large or small simple eyes 5. The abdomen has 10 segments 6. The ninth abdominal segment of both male and female bears a dorsal plate called **sensilium or pygidium**, the tergum of the 9^th^ abdominal segment is modified to form the claspers 7. The penis (aedeagus) of the male is chitinous and coiled and its structure is complex 8. The legs are long, strong and adapted for leaping 9. A number of large spines on the head and the thorax known as **combs** or **ctenidia,** on the cheek it is known as **genal comb** and on the posterior border of the first thoracic segment known as the **pronotal comb**. Important Species: 1. Ctenocephalides canis/ felis -- dog and cat flea, affects dogs ,cats and man 2. Xenopsylla cheopis -- oriental or black rat flea 3. Pulex irritans -- human flea or burrowing fle, affects man primarily but dogs and cats may be infested 4. Tunga penetrans -- jigger or chigoe flea or sand flea affects man rarely pig 5. Ceratophyllus gallinae- common chicken flea 6. Ceratphyllus columbae -- pigeon 7. Echidnophaga gallinacean -- chicken 8. Ceratophyllus fasciatus- rat flea 9. Echidnophaga gallinacean- stick tight flea, affects chicken, dogs, cats and man 10. Spilopsyllus cuniculi -- rabbit flea, but may also affects dogs and cats Life Cycle: Female flea lays up to 20 eggs at a time (eggs are 0.5 mm long, rounded at the poles and pearly white in colour ) \-\-\--2- 16 days (depending on the temperature and humidity)\-\-\-- develop into creature with 3 thoracic and 10 abdominal segment each of which bears a few long hair, creamy yellow in colour and very active hiding from the light, they have masticatory mouthparts and feed on dry blood faeces and organic matter, some larvae may prod the adult flea to produce faecal blood for them to feed upon, they feed in crevices in floors under carpets and in the nest litter or sleeping places of the host animals\-\-\-\-\--imago (young adult) \-\-\-\--adult (the complete life cycle takes 3 wks or 2 years if the temperature is low) Prepuscular -- early a.m. and early p.m. Habits; 1. Both sexes are blood suckers and only adults are parasitic 2. Fleas are less permanent parasites and frequently leave their host. Their longevity (days) varies with: a. Different species of fleas b. Whether they are fed or not c. Degree of moisture in their surroundings, unfed fleas do not live long during summer 3. Not markedly specific for their host and may feed on other host 4. Usual life span is 1-2 years 5. Some species are permanently attached to the host Pathogenesis: Fleas are specially found on animals which are poor in condition or suffering from chronic debilitated diseases. Infected animals become: 1) restless 2.)lose condition 3.) spoil their coats by biting and scratching. A. Direct 1. Allergic flea bite dermatitis. In cats military dermatitis results which is characterized by diffuse alopecia from excessive grooming and scratching due to severe pruritus. 2. Burrowing in of stick- tight flea which causes nodule formation and eventually ulcerations. "Jiggers" causes the same lesions in man but is more slight. B. Indirect 1. Transmission of diseases and Murine typhus (Rickettsia typhi) a. Plague (Yersinia pestis )by Xenopsylla cheopis, Trypanosoma lewisi, C. fasciatus b. Tularemia c. Myxomatosis in rabbits 2. Intermediate hosts of a. Dipylidium caninum (dog tapeworm) b. Ctenecephalides canis and P. irritans c. Dipetalonema reconditum- dog filaroid worm by C. canis Treatment and Control: 1. Give corticosteroids as palliative treatment if there is much distress in flea bite allergy. 2. Application of insecticide dust, spray or shampoo 3. Use of flea collar (causes contact dermatitis)- not recommended 4. Spraying of animal quarters with insecticides. **REVIEW QUESTIONS (40%)** 1. Define paratergal plates, tibial spur, tibial pad,jiggers and dermatitis (5%) 2. Differentiate Family Hematopinidae from F. Padiculidae (15%) 3. Discuss the effects of lice on the host (10%) 4. Discuss the morphological characteristic of Order Siphonaptera(10%) **SUMMATIVE TEST** I. **Answer the following (100%)** 1. Identify the different divisions of parasitology. (10 %) 2. Define veterinary parasitology, host, parasitism, symbiosis and ovipositor (10%) 3. Enumerate the effects of parasites on the host.(10%) 4. Discuss the life cycle of lice (10%) 5. Create an effective control system for lice infestation in domestic animals (10%) 6. Discuss the morphological characteristic of Order Siphonaptera(10%) 7. Differentiate Family Hematopinidae from Family Pediculidae (10%) 8. Discuss how cockroaches can cause animal diseases (10%) 9. Discuss the effects of lice on the host (10%) 10. Discuss the insect flight (10%) **Module 2** Lesson 1 Order Coleoptera Lesson 2 Sub-Order Cyclorrhapa Lesson 3 Sub Family Sarcophaginae Lesson 4 Class Arachnida Lesson 5 Genus Ixodes **LESSON 1** **ORDER COLEOPTERA** **(Beetles)** Beetles are insects from the order Coleoptera in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra distinguishing them from most other insects. The Coleoptera , with about 400,000 species is the largest of all orders, constituting almost 40% of described insect and 25% of all known animal life forms; new species are discovered frequently. Found in almost every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles aften feed on plants and fungi, breakdown animal and plant debris and eat other invertebrates. Some species are serious agricultural pests, while others eat aphids, scale insects, thrips and other plant sucking insects that damage crops. The general anatomy of a beetle is quite uniform and typical of insects. Beetles are endopterygotes, which means that they undergo complete metamorphosis, with a series of conspicuous and relatively abrupt changes in body structure between hatching and becoming adult after a relatively immobile pupal stage. Comprises the largest order (40%) of the Class Insecta General Characteristics 1.Mouthparts adapted for chewing 2.Facultataive parasites 3.Found in water, soil, dung, plants etc. 4.Provide inhalant allergens and direct toxicants 5.Important only as intermediate host in veterinary medicine Morphology: 1. Possess a hard shell-like outer covering on the dorsal region called **elytra** 2. Produce a vesicating substance called **cantharidin** which is found on the whole body primarily on the elytra Important Families 1. Meloidae (blister beetles) 2. Staphylinidae (rove beetle) Pathogenesis: 1. Intermediate Hosts of the ff; a. Gizzard worm (Cheilospirura hamulosa) b. Rat tapeworm (Hymenolepis diminuta) c. Thorny headed worm of pigs (Macracanthorynchus hirudinaceus) 2. Occupational allergic hazard (asthma) **ORDER DIPTERA** **(True flies)** Sub Orders: 1. Nematocera 2. Brachycera 3. Cyclorrhapha General Characteristics: 1. With one pair of membranous wing (**mesothoracic pair**) attached to the mesothorax. 2. Hindwings are rudimentary and referred to as **halteres or balancers**. 3. Mouthparts are adapted for sucking. 4. Undergoes complete metamorphosis. 5. Usually has proboscis but no mandible. NEMATOCERA 1. Family Culicidae 2. F. Simuliidae 3. F. Ceratopogonidae 4. F. Psychodidae BRACHYCERA 1. Family Tabanidae CYCLORRHAPHA 1. Family Muscidae 2. F. Glossinidae 3. F. Argastrophilidae 4. F. Calliphoridae= Sub family a.)Calliphorinae b) Sarcophaginae 5. F. Oestridae 6. F. Cuterebridae 7. F. Hippoboscidae **Sub Order: NEMATOCERA** General Characteristics: 1. The antennae of adults are usually longer than the head 2. Thorax consist of 8 segments 3. No arista 4. The larvae and pupa are usually aquatic 5. The larvae has a well developed head and horizontally biting mandibles 6. The pupa is usually obtectate in type. **Family Culicidae** 1. Considered the true mosquitoes 2. The antennae of the male is plumose and the female is pilose. 3. Sex could also distinguished by the length of maxillary palpus (male: maxillary palpus is as long as the proboscis, female: palpus is shorter than the proboscis except in Anopheles, wherein the female and male maxillary palpi are as long as the proboscis) 4. No simple eyes, but well developed compound eyes. 5. Male mosquitoes feed on juice of plants 6. Female suck blood and make loud noise. Important genera of veterinary importance: 1. Anopheles (crepuscular feeders) 2. Culex (nocturnal feeders) 3. Aedes (diurnal feeders) Life Cycle: The eggs are laid in water or on floating vegetable matter (laid in masses or egg rafts (Culex spp) or singly (Anopheles and Aedes spp). In anopheles the egg is boat shaped and provided with lateral floats\-\-\-\-\-\-\--hatch after 16-24 hours\-\-\-\-\-\-- **larva/wrigglers** (they have well developed head and a distinct thorax or abdomen, they are heavier than water but breath thru siphon tubes \-\-\-\-\--molting 4x in 7 days\-\-\-\--**pupa/tumblers** (they are aquatic and lighter than water, has respiratory or breath trumpets\-\-\--become young adults in 2-3 days\-\-\-\--adult (the male dies after performing its primary function in life. The entire life cycle takes about 2 wks **Differences between Anopheles, Aedes and Culex Mosquitoes** +-----------------------+-----------------------+-----------------------+ | | Anopheles | Aedes and Culex | +=======================+=======================+=======================+ | 1.Eggs | Laid singly with | Single in mass | | | lateral floats | | | | | No lateral floats | +-----------------------+-----------------------+-----------------------+ | 2.Larvae | Parallel to the | Hangs down from the | | | surface no siphon | surface with siphon | | | tube | tube | +-----------------------+-----------------------+-----------------------+ | 3\. Pupa | Short breathing | Long breathing | | | trumphets | trumphets | +-----------------------+-----------------------+-----------------------+ | 4.Adult | Female pulp is as | Palp of the female is | | | long as the proboscis | shorter than the | | | | proboscis | +-----------------------+-----------------------+-----------------------+ | 5.Feeding | Crepuscular (twilight | Diurnal Nocturnal | | | and dawn) | | | | | Legs have | | | | | | | | White bands | +-----------------------+-----------------------+-----------------------+ Pathogenesis: 1. Annoyance and irritation 2. Loss of blood and the wounds caused by their frequent bites are prone to secondary bacterial infection. 3. Interference with feeding habits of milking cows 4. Transmit diseases= (**Aedes** bites in the morning transmit H fever or dengue fever or yellow fever; **Anopheles** transmit human malaria; **Culex** transmit Dirofilaria immitis and Wucheraria bancrofti) Control of Mosquitoes: 1. Physical Means A. Destruction /eradication of their breeding places, a. dispose empty cans and containers b. Cover stagnant pools with soil or drain ditches c. Clear breeding places of vegetation B. Screen stables, barns and animal houses 2. Chemical Means a. Spray breeding places with appropriate insecticides (1% dieldrin,2% lindane, malatahion) b. Use insecticide-impregnated fly baits (dichlorvos strip) 3. Biological Means a. Use of predators like fish and ducks to control larvae and pupa b. Use of bacteria (Bacillus thurengiensis) to kill larva and pupa c. Use of protozoan parasites (Microsporidia species) d. Sterile male technique e. Use of chemical sterilant and attractants Mouthparts of Mosquitoes: 1. Labium --ends distally into labellum 2. Labellum 3. Labrum epipharynx- inverted "u" covers the mouthparts 4. Hypopharynx- carries salivary duct 5. Maxilla and mandible -- piercing structures 6. Salivary duct -- enlarge center of hypophysis which contain the anticoagulant **Differences between male and female mosquito:** +-----------------------+-----------------------+-----------------------+ | | Male | Female | +=======================+=======================+=======================+ | 1. Palpus | As long as the | Palpi are shorter | | | proboscis | than the proboscis | | | | except anopheles | +-----------------------+-----------------------+-----------------------+ | 2. Mouthparts | Adapted for sucking | Adapted for piercing | | | plant juices only | and sucking (blood | | | | meal) for egg | | | | production | +-----------------------+-----------------------+-----------------------+ | 3. Antenna | Plumose | pilose | +-----------------------+-----------------------+-----------------------+ **Family Ceratopogonidae** They are minute insects, known as biting midges, punkies, no- see-ums, gnats General Characteristics: 1. Very small 1-2 mm long 2. Wings have mottled appearance without scale but with hairs 3. Antennae is long and plumose in male but pilose in female 4. Have piercing sucking mouthparts, the mandibles acting like scissors; only females are parasitic (blood suckers) 5. The thorax is humped over the head **Genus Culicoides- biting** midges/punkies/no-see-ums Distribution**-**worldwide They are active at night, attracted to light and animal odour, the females are blood suckers Act as vectors of protozoa and filaroid nematodes like blue tongue and African horse sickness Host are domestic animals and man. Life Cycle; 1. Egg- laid in water, they have a characteristic brown or black colour and may be cylindrical or banana- shaped 2. Larva-freed at 2-9 days; worm like whitish in colour, bearing a small head and 3 thoracic and 9 abdominal segments; the terminal segment bears a few locomotory spines with anal gills but larva breath through the skin; they feed on decaying vegetation. 3. Pupa- formed at 14-25 days; brown obtectate pupa with respiratory trumpets; the body is covered with spines and tubercles; possess a **terminal horn** which enables the pupa to move. 4. Adult- formed at 3-10 days ;only 1-3 mm long. Pathogenic Effects: 1. Bites and sucks blood causing severe annoyance if they are present in vast numbers. It also elicits inflammatory response 2. Transmit filarial worms such as : Dipetalonema perstans, D. streptocara and Monzawella ozardi. They also serve as intermediate host of Leucocytozoon caulleryi 3. It causes " Queensland itch" (sweet itch or sweat itch), it is an allergic dermatitis attributed to immediate type hypersensitivity reaction characterize by loss of hair on the dorsal part of the body which may be aggravated by scratching due to severe pruritus Treatment; 1. Give antihistamines for Queensland itch 2. Application of Benzyl benzoate emulsion Control: 1. Clean the area, remove any floating debris 2. Spraying with dieldrin, benzene hexachloride, DDT **Family Simuliidae** Genus Simulium- Blackflies or Buffalo gants Host: all domestic animals and man Distribution; worldwide General Morphology: 1. Black in colour and thorax humped over the head 2. Piercing proboscis is short 3. With long antennae(11 segments) which are neither pilose nor plumose in different sexes 4. 1.5-5 mm long and the body is covered by short, golden or silvery hairs 5. Wings are broad, clear and not spotted, it has no hairs or scales except bristles which are on the anterior veins, it is held at rest like closed blades of scissors 6. Adult males are holoptic and females are dichoptic Life Cycle: 1. Egg -- laid in stones or plants below surface of water in running streams by inserting its ovipositor into the water. 2. Larva- freed at 4-12 days; cylindrical in shape with posterior sucker-like organ armed with hooks, a brush-like mouth structure is present anteriorly; it possess a **proleg** at its anterior which is used in moving about; it is carnivorous 3. Pupa- formed after 6-8 moults, obtectate pupa in a triangular cocoon, it possess 1 ventral and 1 dorsal respiratory tube 4. Adult Pathogenesis; It is especially troublesome in warm countries. Flies are active during morning and evening resting only during the hot part of the day on the underside of leaves under the ground. 1. Bite and blood sucking ability-in large ruminants, it cause variable severity of petechial haemorrhage over the head, abdomen, head and ears. Vesicles may also be formed which bursts and take weeks to heal. It causes anemia in poultry. 2. Vector of Eastern equine encephalitis and vesicular stomatitis viruses. Control: Quite difficult because they could fly as far as 3-5 km or more. WHO points out that adults prefer to get into the clothing before they bite so repellants applied to clothing may help. **Family Psychodiidae** **Genus; Phlebotomus**- "Sandflies or owl Midges" Host; Mammals, reptiles,birds and man Distribution :tropics and sub-tropics General Morphology: 1. Small, moth-like flies about 5.0 mm long 2. Body and wings are hairy 3. Legs are long and stilt-like 4. Wings are held roof-like over the abdomen during rest 5. Short or medium --length mouth parts 6. With long antennae (16 segments) with bladed appearance 7. Palpus recurved and hairy Life Cycle; 1. Egg- laid in moist, dark places (rock crevices) 2. Larva- resembles small caterpillar; feeds on feces of lizards and bats and dry leaves, takes 4 larval instars Pathogenesis: They are parasitic during night-time and are weak fliers. Some species of females are blood suckers/ 1. Bite- causes inflammatory response; pruritus 2. Vector of Leishmaniasis (L. tropica, L. donovani) and Oroya fever (Bartonella sp) Control: Removal of dense vegetation **Sub Order Brachycera** **Family Tabanidae- Horse flies or Breeze Flies** Genera: 1. Tabanus 2. Chrysops 3. Pangonia 4. Haematopota Host: Large domestic or wild animals and man but small animals and birds may also be attacked Distribution: Worldwide General Morphology: 1. Large robust flies with powerful wings and large eyes 2. Eyes are holoptic in males and dichoptic in females 3. Antennae have 2 short basal segments, the third segment is large and usually ringed or annulated. 4. Proboscis is relatively short in Tabanus and Haematopota, longer in Chrysops and very long in Pangonia which projects forward. The former are soft and hangs down 5. Eyes are metallic in colour 6. The wings of Chrysops has a dark band and it is divergent at res, Hematopota has mottled wing, Tabanus has a clear wing which is horizontal at rest Life Cycle : 1. Egg- laid in water vicinity usually in plant leaves 2. Larva- freed in 4-7 days; maggots like with 11 segments, mouthparts are already prehensile and masticatory; they are carnivorous, feeding on small crustacean or themselves; it bears a siphon tube. 3. Pupa- formed in 10-14 days; sub cylindrical 4. Adult- most active and more common in summer; females are known blood suckers while males feed on honeydew or flower juice as do females when a suitable host is absent; they feed every 3 days and rest for a few hours. Pathogenesis: 1. Bite- painful and irritating, causes weal on soft skinned animals; their bites leave wound that attracts other non-biting flies which are vectors of diseases. 2. Vector of Loa loa and Trypanosoma species. Pangonia is not adapted for piercing and proboscis is used for sucking up spilled blood. The Brachycerans have cross veins on wing and their mouthparts are specially adapted for slashing-sponging purposes. **REVIEW QUESTIONS (40%)** 1. Discuss the differences between Anopheles and Culex mosquitoes(10%) 2. Discuss the differences between male and female nosquitoes(10%) 3. Create an effective control for Culicidae(10%) 4. Create an effective control for Muscidae(10%) **LESSON 2** **SUB-ORDER CYCLORRHAPA** This sub-order consists of a number of families of flies which are important as parasites or as vectors of disease in animals. Since the classification of a number of genera is variable they will be discussed for simplicity, under four major families, the Muscidae, Calliphoridae, Oestridae and hippoboscidae. Given that there are at least 125 families and 120,000 species of Diptera, unsurprisingly, their identification can be problematic. Some families are very small and obscure and identification to genus or species may require microscopic examination of the number and position of particular setae, or examination of internal stuctures such as the male genetalia. Other families and genera can be easily recognised. Family Muscidae: Genera: 1. Musca 2. Stomoxys 3. Hematobia 4. Fannia Genus Musca**:** **Species: Musca Domestica -- "Common housefly"** Host: they are non- obligatory parasites but they can feed on a wide variety of animal secretions and are especially attracted to wounds Distribution : Cosmopolitan Morphology: 1. 5.5 to 7.5 mm, light to dark gray in colour 2. The mouthpart is adapted for sponging which is obvious only when extended during feeding (**pseudotrachea**) at the tip of the labella. This structure is capable of straining food of only 4 um diameter. Liquefiable solid food such as sugar may become fluid before it is sucked up by injecting on to it saliva and crop fluid called **vomit drops**. This is important in its disease -- transmitting capacity, 3. Another important morphologic feature is the presence **of sticky hairs on pad-like structures** at the end of the clawed legs. These enable the fly to adhere to smooth surfaces and more importantly transmit diseases. Life Cycle: 1. 100- 150 eggs are laid preferably on horse manure but may also be laid on feces of man, rotting organic materials and refuse. 2. After 12-24 hours, whitish segmented larvae (maggots) are produced which feeds on decomposing organic matter. 3. Three (3) instars follow within 3-7 days developing a rigid dark brown pupa which is barrel-shaped. 4. The adult develops after few days. The complete lifecycle is from 10-14 days, while the adult fly lives about a month, they rarely hibernate. Pathogenesis; 1. Source of annoyance 2. The fly regurgitates at frequent intervals to aid its feeding (vomit drop) and it defecates at random; it mechanically transmits diseases such as: Control: Improve sanitation and reduced breeding places by: 1. Stack manure in large heaps when the heat of fermentation will kill the developing stages of flies and apply insecticides on the surface, 2. Kill flies by using aerosol space sprays, residual insecticide, fly baits, insecticide impregnated ear tags, tail bands and halters and insecticide dust bags in cattle. 3. Proper collection and disposal of garbage. **Species : Musca autumnalis** -- "face fly" Hosts: feeds on secretions of animals from the eyes, nose and mouth as well as on the wounds left by biting flies Distribution: Western countries Life Cycle: Eggs are deposited in fresh cattle feces Pathogenesis: Flies huddle together in the face region, the animal becomes nervous and their normal grazing behaviour become interrupted **Genus: Stomoxys** Species: Stomoxys calcitrans- "stable fly," " biting housefly" Hosts: most animals and man Distribution: worldwide General Morphology: 1. About as large as Musca domestica 2. Superficially similar with the common housefly except that the proboscis is conspicuous and forward projecting. 3. The labellum has teeth called **denticles or prestomal teeth.** Life Cycle: 1. Lays 25- 50 eggs in moist decaying vegetable matter such as hay or straw contaminated by urine 2. Larva is produced after 1-4 days, it resembles the larva of Musca domestica; it feeds on decaying vegetable matter 3. After 6-30 days, the pupa develops 4. It becomes adult after 6-9 days 5. A blood meal is necessary before the ovaries mature 6. The complete life cycle takes about 12-60 days Pathogenesis: 1. Great annoyance of grazing cattle because their bites are painful 2. Both male and female are blood suckers 3. Vector of : Trypanosoma evansi, T. equinum, T. gambiense, T. rhodesiense, T. brucei, T. vivax, Bacillus anthracis 4. Intermediate host of Habronema majus Control: 1. Destroy breeding places by regular removal of moist bedding 2. Prevent accumulation of heaps of weeds and vegetable refuse 3. Strategic application of insecticides **Genus: Hematobia/Lyperosia** Species: Hematobia/Lyperosia irritans- horn fly Host: cattle and buffalo Distribution: most parts of the world particularly the far east Morphology: 1. Smallest of the blood sucking muscids; only 4 mm long 2. They generally remain in their host leaving only to fly to another host or female to lay eggs in freshly passed feces Life Cycle: 1. Eggs are laid in fresh dung of cattle and buffalo 2. After 20 hours the larvae are liberated and burrow into the dung and feed on it 3. The pupa is produced after 4 days 4. After 6-8 days, the adult arises Pathogenesis: 1. They are blood suckers 2. Heavy burdens cause injury and irritation due to the constant piercing of the skin, the animal develops sores and wounds attracting screw worm flies. 3. It transmits Stephanofilaria stilesi (cattle skin parasite) Control: Regular spraying with insecticides Species: Hematobia exigua- buffalo fly Host: Buffalo and cattle Distribution: India, Malaysia, China and Northern Australia Morphology and Life Cycle: same as H. irritans Pathogenesis: 1. Heavy infection causes considerable weight loss and low milk yield 2. It transmits T. evansi and Habronema spp. **Genus: Fannia** Species: Fannia canicularis- breeds on decaying vegetable matter and refuse Fannia scalaris- latrine fly , breeds on human feces Pathogenic Significance; Found in the discharge of male and female which may lead to urogenital myiasis Family: Glossinidae Genus: Glossinia -- tse tse flies Species : Glossinia palpalis, Glossinia morsitans Host: Various mammals, reptiles and birds Distribution; Africa Morphology 1. Narrow, yellow to dark brown flies with long, rigid and forward- projecting proboscis 2. Distinguished from all other flies by the characteristic cleaver (hatchet) cell in the wings Life Cycle: 1. Male and female sucks blood, the female is larviparous producing only 1 larva at a time for a maximum of 8-12 larvae 2. The larva grows in the uterus of the female and the gestation lasts about 10 days (the female doesn't feed but remain in shelter throughout gestation. 3. A creamy white segmented larva is expelled in water, sand or in humus where it wriggles in loose soil; it possesses a posterior-ear shaped protuberance known as **polypneustic lobes**- which has respiratory function. 4. A rigid dark brown, barrel- shaped puparium is formed 5. The adult is formed after 4-5 weeks 6. The entire life cycle takes 4-5 months Pathogenic Significance**:** 1. They are blood suckers 2. Their bites are painful and caused marked irritation 3. It is aground flier and hunt by sight 4. It transmits Trypanosoma organisms particularly the causative agents of sleeping sickness Control:\ A. Previous: 1. Large scale killing of game animals which are reservoir hosts 2. Clearing large areas of bush to destroy the fly habitat (this is fairly successful but now unacceptable on ecological and economic backgrounds. B. Current: 1\. Insecticides sprayed from the ground or by aircraft 2\. Non- residual or residual insecticide 3\. Trapping- use dark cloth (where they are attracted) impregnated with insecticides 4\. Catching with hand nets (not practicable) 5\. Use of fly screens 6\. Biological control -- release sterile males **Family Calliphoridae** Sub families: 1. **Calliphorinae**- blow flies 2\. **Sarcophaginae**- flesh flies **Sub-family Calliphorinae** Genera: 1. **Lucilia** 2\. **Calliphora** 3\. **Phormia** 4.**Chrysomia** **Genus Lucilia** Species: Lucilia cuprina- green bottle fly Host: Sheep and man (wounds) Morphology: 1. With metallic colours being bright green or bronze 2. Measures 8-10 mm with brownish red eye **Genus Calliphora** Species: Calliphora erythrocephala- blue bottle fly Host: sheep Morphology: 1. Body has a metallic blue sheen 2. Measures 12mm with red eyes **Genus Phormia** Species: Phormia regina -- black blow fly Phormia terrae-novae Host: Sheep Morphology: Its thorax is black, with a metallic blue-green sheen **Genus Chrysomia** -- Screw worm fly Specie: Chrysomia chloropyga Host: man and domestic animals Morphology: 1. Medium sized stout, bluish green fly 2. The face is orange yellow General Life Cycle of blow flies: 1. Eggs are laid in carcass, wound or soiled wool since the adults are attracted by decomposing matter 2. After 8 hours to 3 days the larva is formed, after 2 ecdyses, they became full grown maggots which may be smooth or hairy 3. They move to the dry part of the wool and pupate 4. Adults develop in 3-7 days Pathogenesis: These flies produce calliphorine myiasis\* of sheep or blowfly strike\*\* \***Calliphorine myiasis**- infestation of living animals with the larvae of dipterous flies \*\* **Blowfly Strike**- the laying of eggs on the wool by the fly is referred as **blow,** and the development of the larvae (maggots) and damage of the tissue is the **strike**. Classification of Myiasis Flies: 1. Primary flies -- initiate the strike by laying eggs on the living sheep; it develops during autolysis and early bacterial decomposition 2. Secondary flies -- lay their eggs on the sheep already struck; the larvae extend the injury done by the primary larvae; it develops during the succeeding phase of liquefaction 3. Tertiary flies -- come last of all when the carcass begin to dry out and does little further damage to the sheep **How myiasis is developed**: 1. Presence of wound under the wool 2. Wet conditions 3. Skin becomes exudative 4. Attraction of blowflies 5. Laying of eggs by flies on the wool 6. Larvae secrete proteolytic enzymes 7. Tissues are digested and liquefied while the larvae feed on them 8. Secondary larvae may develop as they are attracted by the odour of liquefying tissues 9. Burrowing into the skin by the secondary larvae which may be complicated by secondary bacterial infection **Effects to the Animal:** 1. Irritation -- the animal is rendered weak that prevents it from feeding properly 2. Toxemia -- toxic substances may be produced from the lesions 3. Reduced value of the fleece 4. Reduced meat and milk production Treatment: 1. Surgical removal 2. Use of low concentration dressing compounds **Genera of the Sub-family Calliphorinae which does not produce blowfly strike in sheep:** 1. Callitroga 2. Cordylobia 3. Booponus **Genus Callitroga --Screw worms** Species: Callitroga hominivorax C. macellaria Host: man and other domestic animals Distribution: America Morphology: bluish green, measures 10-15 mm Life Cycle: 1. Eggs are laid at the edge of the wound or on the carcass 2. Larvae are produced after 10-12 hours 3. After 3-6 days the larva pupates 4. The adult is formed after 3-7 days Pathogenesis: 1. Rainy weather predispose the animal to screw worm infestation, they penetrate into the tissues, which they liquefy and extend the lesion considerably 2. The animal becomes weak and restless, the effect is more on the production aspect Treatment: 1. Thorough cleaning of wounds and dressing it with appropriate antiseptics. 2. Destroy larvae **Genus Cordylobia** -- tumbu fly, skin maggot fly Host: man, small rodents, monkeys, dogs Distribution: Africa Morphology: 1. Measures 9.5 mm 2. Light brown in colour Life Cycle: 1. Eggs are laid in sleeping places of man and other animals 2. Larvae are produced after 2-4 days 3. The larvae penetrate into the skin and becomes a pupa after 8-15 days 4. Adult develops after 3-4 wks Pathogenesis: Larva is situated in a swelling which is about 1 cm in diameter, painful and has a small central opening. Treatment: Press out larvae and apply disinfectant **Genus: Booponus** Species: Booponus intonsus- foot maggot fly Hosts: Cattle, carabao, goats Distribution: Philippines and Celebes Life Cycle: 1. Eggs are laid on the hairs along the coronet and the posterior part of the hoof 2. Larvae penetrate on these parts and produce wounds 3. The pupa is produced after 2-3 wks 4. After 10-12 days the adult develops Pathogenesis: 1. Animals are rendered lame due to pain in the foot parts 2. Secondary bacterial infection particularly foot rot infection complicates the condition **REVIEW QUESTIONS (40%)** 1\. Define the following : pseudotrachea, vomit drops, denticles, polypneustic lobes.(10%) 2\. Differentiate Musca domestica from Musca autumnalis with regards to their morphological characteristics(10%) 3\. Dicuss the pathogenesis of blowfly strike and foot maggot fly (10%) 4\. Differentiate green bottle fly from blue bottle fly with regards to their ability to cause diseases (10%) **LESSON 3** **FAMILY SARCOPHAGIDAE** **FLesh flies** The Sarcophagidae or flesh flies such as Sarcophaga and Wohlfahrtia are widely distributed and lay their larvae in sores, wounds or decomposing flesh, they primarily affect man and only occasionally animals. The larvae can cause great disfiguration. The Sarcophagidae are grey-black, non metallic, medium to large flies with prominent stripes on the thorax. There are over 2,000 species in the family Sarcophagidae, divided into 400 genera. Most species of Sarcophaga are of no veterinary importance, breeding in excrement, carrion and other decomposing organic matter. The only important genus of the family Sarchophagidae containing species which act as agents of veterinary myiasis is Wohlfahrtia. **Genera: Sarcophaga and Wohlfahrtia** Hosts: man and occasionally animals, they are larviparous, laying their larvae in wounds or sores and decomposing materials Effects: cause great disfiguration Family: Gasterophilidae Genus: Gasterophilus -- Bot flies Species: 1. Gasterophilus intestinalis- common bot fly (found in cardiac portion of the stomach) 2. Gasterophilus nasalis -- throat bot fly (found in the pylorus and duodenum) 3. G. hemorrhoidalis- nose bot fly ( found in the stomach and rectum) 4. G. pecorum Hosts: horse and donkey, rarely dogs, pigs, birds and man Distribution: worldwide Morphology: 1. Adult- robust black fly 2. Larva- cylindrical, reddish orange with rudimentary mouthparts Habits: 1. Prevalent during summer season 2. Live only a few days, rarely up to 3wks 3. Female hovers around the animal and repeatedly darts at it to glue an egg to a hair Life Cycle: 1. Eggs are laid on: a. Hairs of leg and shoulder (G. intestinalis) b. Intermandibular area (G. nasalis) c. Around the lips (G. hemorrhoidalis) 2. Eggs are ingested by grazing horses (G. pecorum) 3. Eggs are hatched as stimulated by warmth in licking (other spp) 4. Larva moves by crawling into the mouth or to the tongue by licking 5. Buccal mucosa 6. Pharynx 7. Esophagus 8. Stomach 9. Larvae detached and passed out in feces 10. Pupa 11. Adult There is only one generation of flies/year in temperate countries Pathogenic Effects: 1. Annoyance 2. Stomatitis with tongue ulceration 3. Ulceration in the stomach which may be dramatic in appearance but obscure pathogenic significance; reattachment to the rectum may cause irritation 4. Accidental larval infection in man is limited to skin known as **creeping eruptions.** Diagnosis: Examine sites at which eggs are deposited and larvae in the pharynx can be seen in direct inspection. Treatment: Carbon disulphide \` Trichlorfon Dichlorvos Ivermectin Family : Oestridae General Characteristics: 1\. Have rudimentary mouthparts and do not feed 2\. Larvae (maggots) are parasitic Genera: Oestrus Hypoderma Rhinoestrus Genus: Oestrus Species: Oestrus ovis -- sheep nasal fly/ nasal bots Hosts: sheep and goats Distribution: Worldwide Life Cycle: 1\. Viviparous female infect sheep by squirting a jot liquid with larvae during flight (up to 25 at a time) **2.** Larvae migrate to nasal passages feeding on mucus whose secretion is stimulated by their movements (L1-L2) 3.Frontal sinus (L3) 4\. Back to nostrils 5\. Pupa in the ground 6.Adult Female survives for 2 wks only but could deposit 500 larvae in the nasal passages of the sheep. Pathogenic Effects: 1.causes **false gid** 2.Nasal discharge, sneezing, rubbing of nose to fixed objects 3.Nervous signs- incoordination and high steeping gait 4.Adult flies cause the animal to panic, stamp their feet, bunch together and press their bodies together and against the ground; feeding interruption may lead to failure to gain weight. Genus: Hypoderma- ox warbles Species : Hypodorma bovis "northern cattle grub" Hypoderma lineatus " common cattle grud" "heel fly" Host : cattle : rarely horse and man Life cycle : 5. Eggs are laid singly at hairs of legs above the hock (H. bovis) or in rows of 6 more at hairs below the hock (H. linoatum) 6. Larva crawl down the hair 7. Penetrate hair follicle 8. Migrate towards towards the diaphragm via the SQ tissue up the leg (L1) -- aided by paired mouth hooks and socreted protoolytic enzymes 9. Submucosa of osophagus (H. linoatum) (L2) opidural fat of spinal canal (H. bovis) 10. Reaches the SQ tissue of back (L3) and form swollings (warbles) 11. L3 creates a perforation and apply their spiracles to the sporture for breathing purposes 12. Larvae falls in the ground and pupate 13. Adult Pathogenic Significance : 1. Economic lesson due to fly attack a. "gadding" animals panic when attacked by buzzing flies especially h. bovis which lay its egg singly therefore has to repeatedly attack the animal. The animal tends to run away aimlessly and injure themselves on fences or may die when they fall in water over heights b. Interrupted feeding -- low milk and meat yield 2. Downgrading and condemnation of hides 3. Carcass depreciation -- the flesh under the skin infested with L3 may be damaged producing the characteristic greenish gelatinous tissue which has to be trimmed "butchor's jelly" 4. If the larva dios in the spinal cord, the highly toxic protoclytic enzymes may cause paraplegia; in the esophagoal wall, it may cause bloat due to esophagoal stricture 5. Aborrant migration due to other organs may cause anaphylactic reaction or signs relative to the organ 1. No appreciable until the larvae appear along the back when the swolling can be folt and soon Treatment : 1. Removal of larvae (mechanical) -- ineffective who larvao is immature because its rupture may lead to inflammation, abscess formation or anaphylaxis 2. Larvicide -- oraganophosphorous compounds and ivormoctin Control : regular application of organophosphatos during the early summer Genus : Rhinoestrus Species : Rhinoestrus purpurensis "gadfly" Host : larval stages are obligatory parasites of the nasal sinuses and larynx of horses Dist : Europe, Africa , Asia Disease : Opthelmomyiasis and nasomyiasis of man Family : Cuterebridae Genera : Cuterebra Dermatobia Genus : Cuterebra Host : rodents ; occasionally infects cats, dogs, and humas Site : skin Dist : Northern America Pathogenesis effect : cyst-like subcutaneous lesion Treatment : surgical removal Genus : Dermatobia Species : Dermatobia hominis "tropical warble fly" Hosts : man, domestic and wild animals including birds Life cycle : 1. Adult flies do not feed and nourishment is derived from food stored during the larval period 2. Adult female rest on leaves, capturos a mosquito or other blood-sucking fly 3. Glues a batch of egg to the abdomen of the captive fly in 7 days (L1 develops within the egg) 4. Eggs hatch when insect land on a warm-blooded animal 5. Larvae penetratre skin migrate to the SQ tissue 6. Larvae penetrate skin and migrate to the subcutaneous tissue 7. Eggs may be deposited on damp clothes 8. Man are infected by association with domestic animals 9. Larvae grows undes the skin and produce a swolling with a contral opening 10. Larve escapes and pupates in the ground 11. Adult Pathogenesis effects : 1. "Uva"- swolling in various bod parts which may suppurate and cause severe pain 2. Attracts myiasis flies Treatment : surgical or mechanical removal Control : application of larvicides although costly because there are 3 generations a year therefore if cost is acceptable frequent sprays should be done Section : Puripara General Characteristics : 1. Abberant Diptera 2. Female give birth to larvae which are ready to pupate 3. With strong claws by means of which the parasite clings to the hairs or feathers of host 4. With piercing blood-sucking mouthparts 5. They may be permanent parsites Family : Hippobosciadae Genus : Hippobosca " forest flies" Species : Hippobosca equine -- worldwide H. rufipes - Africa H. maculata - tropics and subtropics H. capensis - Asia and Africa Hosts : horse, cattle and other domestic animals may be affected including birds; H. maculate specifically affects dogs Morphology : 1.0 cm in length; pale reddish brown with yellow spots on the distinctly segmented abdomen; have wings; proboscis are retracted when not feeding Life cycle : deposit mature larvae singly on dry soil or humus (5-6 larvae max.) pupate immediately and chane its color from yellow to black adult Habits : 1. Adult flies are most frequently in warm weather 2. Their preferred site to attack are the perineum, between the hind legs and pubis but they may also bite other parts of the body 3. They are strong fliers but they could note travel long distances Pathogenec significance : 1. Annoyance to animals which are not accustomed to attack 2. Transmits Trypanosoma theileri of cattle and Hemoproteus of anatids and birds Control : topical application of insecticides with repellent and residual effects (Pyrethrin and Permethrin) Genus : Melophagus "Sheep Ked" Species : Melophagus ovinus Distribution : worldwide but more common in temperate countries Morphology : hairy wingless insect 5.0 mm with strong legs and stout claws Life cycle : attaches its immotile larvae to the wool by means of a stickly sustance pupa 19-36 days adult 3-4 days Copulation Gestation (10 to 12 days) Habits : 1. Permanent ectoparasite 2. Female ked lives 4 to 5 months in a sheep and may produce 10-15 larvae 3. Engorged females can live up to 8 days off the host 4. Pupae removed from the sheep could still hatch if the temperature is favourable but will die soon if they don't find a sheep to feed on Pathogenic significance : 1. Anemia 2. Wool damage -- severe irritation will cause the animal to bite, rub or scratch itself; ked's feces stain the wool which don't wash out readily 3. Transmits Trypanosoma melophagium which is actually non-pathogenic Control : rarely done because the routine use insecticide for the control of major ectoparasites like blowflies and ticks reduces ked population Genus : Pseudolynchia Species : Pseudolynchia canariensis/maura Host : pigeons and a few wild birds Distribution : warm countries Morphology : resembles sheep ked bit has wings Life cycle : Larvae laid in dark crevices of pigeon house nests, or on the host few hours pupa 23-31 days adult Habits : 1. Blood sucking 2. Female produces 4-5 young during life Pathogenic significance : 1. Painful bites 2. Anemia in your Ha 3. Transmits protozoa in pigeons **REVIEW QUESTIONS (40%)** 1. Discuss the life cycle of bot flies (10%) 2. Differentiate gadding from false gid (10%) 3. Discuss the life cycle of Hypoderma species (10%) 4. Discuss the pathogenic significance of Family Oestridae (10%) **LESSON 4** **CLASS : ARACHNIDA** This class includes the ticks and mites which are of considerable veterinary importance and also the spiders and scorpions. They differ from the insect in that the adult has four pairs of legs and the body is composed of a cephalo-thorax and abdomen. The unsegmented cephalo-thorax is usually covered dorsally by a solid carapace. In primitive forms the abdomen is divided into two; however, in most forms this segmentation has been lost. The mouthparts are extensively modified and carry two pairs of appendages, the first called the chelicerae and the second the palps. Antennae are absent. Members of class Arachnida are a highly diverse group of largely carnivorous, terrestrial, chelicerate arthropods. **General Morphologic Characteristics:** 1. body is not divided into head, thorax, and abdomen 2. antennae, compound eyes and mandibles are absent 3. wingless 4. body segmentations are divided into: a. gnathosoma/capitulum/false head \- chelicerae (1^st^ appendage) for food processing \- pedipalps (2^nd^ appendage) for grasping, locomotion and reception of stimuli; the basal joints may bear teeth which helps in chewing the prey (spiders and scorpions) called gnathobases \- hypostome b. idiosoma \- 4 walking leg pairs (3^rd^ to 6^th^ appendage) \- remaining segments 5. possess toxic glands and claws 6. breathe through lung books and tracheae 7. larval stages have 3 leg pairs, nymphs and adults have 4 pairs **ORDER : ACARINA** **(Ticks and Mites)** **Suborder: Ixodoidea (Ticks)** Families: Argasidae (soft tick) Ixodidae (hard tick) General Chacteristics: 1. blood sucking 2. chelicerae and hypostome are armed with denticles 3. the genital opening and anus are both located ventrally at the level of the 2^nd^ leg pair and the 4^th^ pair of leg respectively. 4. Haller's organ which is used in host seeking. If present, could be found on the Taurus of the first leg pair. **Family Ixodidae** **MORPHOLOGICAL** 1. Shield or scutum covers the entire diorsal surface of female scutum size remains constant during engorgement of female and thus covers a progressively smaller proportion of dorsum. 2. The capitulum projects anteriorly and is easily visible from above **BIOLOGICAL** 1. Eggs are laid in a single batch of thousands 2. There is only one nymphal stage 3. Larvae, nymphs, and adults feed only once in each stage. Male ofted die after mating; female always die ovipositing 4. They require several days to complete engorgement 5. When feeding, secretes a cement that binds the mouth part firmly to the skin to prevent blood leakage **Family Argasidae** 1. There is no scutum. The cuticle is covered with mammilations or spines. Sexual dimorphism is limited to slight differences in the genital opening. The male opening being smaller and more arcuate 2. The capitulum is subterminal in adults and usually not visible from above. Larvae and nymphs may have terminal capituli 1. Eggs are laid in several batches of hundreds 2. They are usually two or more nymphal stages 3. They usually infest nests, burrows, buildings and attach to sleeping hosts 4. Adults feed to repletion in minutes to hours. Larvae feed for extended period as do nymphs of [otobius] [spp] 5. When feeding continues to lacerate the capillaries by the chelicerae **Family: Argasidae (soft ticks)** General characteristics: 1. Eyes are absent or there may be two pairs situated laterally on the supracoxal folds 2. The margin of the body is distinctly flattened and usually structurally different from the dorsal surface of the body. The flattened margin remains distinct even when the tick is fuly fed. A [lateral] [sutural] line is present. 3. The dorsal surface often bears small, rounded "buttons" with a pit in the middle. There is often a hair on the bit. **Genus: Argas** Species: [Argas] [persicus] "fowl tick or blue bug" \- found in domestic poultry in the tropics but not in the Philippines [A.] [Reflexus] \- found in pigeons **Morphology:** 1. Image measures 4-10 by 2.5-6 mm, oval in shape, narrower anteriorly than posteriorly 2. Edges of the body are sharp 3. Engorged tick has a slaty-blue color while a starved tick is yellowish brown **[Argas] [persicus] adult** **Habits:** 1. Nymphs and adults feed for about 2 hours at night once a month 2. Females lay a batch of egg after each meal 3. Larvae can live without food for 3 months 4. Nymphs and adult survive starving for about 5 years **Pathogenesis:** 1. Restlessness at night resulting to loss of productivity 2. Causes anemia in heacy infection 3. Causes tick paralysis in ducks 4. Transmits: a. [Borrelia] [anserina] (fowl spirochetosis) b. [Aegyptienella] [pullorum] (Aegyptianellosis) c. [Anaplasma] [marginale] (Anaplasmosis) **Control:** 1. Remove birds from houses and place in wooden crates, the larvae will then drop off within 10 days. 2. Clean houses aand spray with acaricides then return birds **Genus: Otobius** **Species:** [Otobius] [megnin]i "spinose ear trick" -larval and nymphal stages are ear parasites of dogs (primarily) and other domestic animal including man -absent in the Phil. **Morphology:** 1. Integument of adult is granulated 2. Capitulum is distant from anterior margins in adults but near in nymphs 3. Eyes are absent 4. Hypostome is vestigial in adults but well- developed in nymphs 5. Body is bluish grey; legs, mouthparts, and spines are pale yellow 6. Nymphs are widest at the middle and skin is mammilated bearing numerous spine-like processes; adults which are non-parasitic. Have a middle constriction giving the body a fiddle- shape **[Otobius] [megnini] adult** **Habits:** 1. Adults do not feed but female may lay 500-600 eggs 2. Oviposition may last for as long as 6 months. The female dies afterward but unmated female lives longer than a year. 3. Unfed larvae can live 19-63 days at room temperature **Pathogenesis:** 1. Irritation and inflammation on the ear canal; secondary bacterial infection may extend inwards with serious results 2. Anemia 3. Loss of condition; animal exudes waxy or oily material from the ears that the animal tends to shake the head and scratch the ears **Treatment:** Optical drops of acaricide and antibiotics. **Genus: Ornithodoros "sand tampans"** **Species:** [Ornithodoros] [moubata] -affetcs man, various dom. And wild animals including birds in Africa [O.] [savignyi ] -domestic animals and man in Africa and India [O.] [turicata] -domestic animals and man in US **Morphology:** 1. The capitulum is either subterminal or relativiely far from the anterior end. Lying on the ventral side of the body 2. The hypostome is well-developed 3. There may or may not be eyes 4. The body is quite flat. But its dorsal side is markedly convex when the tick is engorged **[Ornithodoros] [moubata] adul

Veterinary Entomology & Protozoology (VPAR 131) Course Outline, DON MARIANO MARCOS MEMORIAL STATE UNIVERSITY PDF

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