PDF - Fundamentals of human body II: Arthropods

‫جامعة مصر للعلوم و التكنولوجيا‬ ‫كلية الطب البشري‬ ‫قسم علم الطفيليات‬ Fundamentals of human body II: (FHB102-2) “BASIC INFECTION, INFECTION CONTROL AND VECTORS OF DISEASE TRANSMISSION...

‫جامعة مصر للعلوم و التكنولوجيا‬ ‫كلية الطب البشري‬ ‫قسم علم الطفيليات‬ Fundamentals of human body II: (FHB102-2) “BASIC INFECTION, INFECTION CONTROL AND VECTORS OF DISEASE TRANSMISSION Arthropoda Parasitology Trematoda Helminths Cestoda Nematoda According to motility: Protozoa amoebae - flagellates - ciliates - Sporozoa Class: Insecta Arthropods Class : Arachnida Class : Crustacea  Classification of arthropods of medical importance Medical Entomology is the science that deals with Arthropods the study of arthropods that cause or transmit diseases to man. Arachnids Arthropods Insects Crustaceans are invertebrate animals, Acarina where body parts articulate with each other 3 pairs of legs 4 pairs of legs Cephalothorax Head Body not well Segmented Thorax differentiated abdomen abdomen IDENTIFY? Insecta WHY? Arachnida Acarina Crustacea WHY? WHY? Types Of Metamorphosis (Development) Of Arthropods  Types Of Metamorphosis (Development) Of Arthropods I-Complete metamorphosis (Holometabolous):- The developmental stages are completely different from the adult (egg → larva → pupa → adult) e.g. mosquitoes. II- Incomplete metamorphosis (Hemimetabolous):- The immature stage (nymph) resembles the adult but is sexually immature (egg→ nymph → adult) e.g. lice.  Medical importance of arthropods (how they affect the health of man): ‫مسبب لالمراض‬ I. Causing Diseases (Agents Of ‫ناقل لالمراض‬ ‫رهاب الحشرات‬ Diseases And Discomfort): II. Transmitting a. Envenomization i.e. inoculation of Disease Agents: III. Entomophobia poisons derived from certain glands and injected in the human body e.g. ticks, (act as vectors that (exaggerated fearing spiders, and scorpions. transmit diseases to response of insects or humans) arthropods that may b. Invasion of tissues e.g. scabies and lead to nervous myiasis. disorder): c. Dermatitis and allergic skin lesions e.g. cockroaches and (atopic allergy) (e.g. mosquitoes, fleas, Arthropods (Vector) scorpions. lice, and bugs and mites). Borne Diseases d. Nuisance, annoyance, and disturbance that may be caused by painful bites of some ectoparasites e.g. bugs. Venomous ‫ سام‬arthropods (stings) ‫لدغة‬ Wasps ‫ الدبور‬and bees ‫النحلة‬ Spiders ‫العنكبوت‬ Centipedes 44 ‫ام‬ Scorpions ‫العقرب‬ Arthropods Borne Diseases = Vector Transmitted Diseases How could man acquire arthropod-borne diseases?  Mechanical transmission The arthropods act as PASSIVE CARRIERS of the disease agents without any cycle, multiplication, or development. It is divided into: *Direct:- Inoculation of the organisms during insect feeding e.g Stomoxys Trypanosomes. *Indirect:- Contamination by the organisms attached to the hairs or body parts of the non-biting arthropods e.g. house fly which carry helminthic ova, protozoal cyst, pathogenic bacteria & viruses from refuse or excreta to the food of man.  Biological transmission: Arthropods play an essential role in the life cycle of the organism during its development and ⁄or multiplication. Types: YOU HAVE TO COMMENT ON change in morphology AND/OR in number of the transmitted organism: ❑PROPAGATIVE: only increase in the number of the organism inside the vector. E.g. Plague in fleas ❑CYCLO-PROPAGATIVE: increase in number and change in morphology of the organism. E.g. malaria parasites inside female Anopheles ❑CYCLO-DEVELOPMENTAL: only change in morphology of the organism. E.g. Wuchereria bancrofti inside female Culex ❑TRANS-OVARIAN (vertical transmission): organism passes to the offspring. E.g. Zika virus inside female Aedes especially in bad climates. 1- When the organism changes inside the vector in both Number and morphology, the transmission type is? A) Cyclopdevelopmental B) Cyclopropagative C) Direct mechanical D) Indirect mechanical E) Transoverian 2- When the organism passes to the offspring, which of the following this type of transmission is called? a. Cyclo-developmental b. Cyclopropagative c. Propagative d. Trans-ovarian  Arthropods of Medical Importance belong to 3 Classes: Class INSECTA (e.g. mosquitoes, flies, lice, fleas, and bugs ). Class ARACHNIDA (e.g. ticks and mites). Class CRUSTACEA mostly aquatic or semi-aquatic (e.g. Cyclops). Learning needs for written exam GD Development Habits and bionomics Medical importance and type of transmission Methods of control Flies 4/1/22  Flies ❖ Class: Insecta (having a Head, Thorax, abdomen, and 3 pairs of legs) ❖ Order: Diptera (having 1 or 2 pairs of wings) ❖ Family: 4 main families of Flies ✓ Muscidae (Musca, Stomoxys, Glossina) ✓ Calliphoridae (Calliphora, Lucilia) ✓ Sarcophagidae (Sarcophaga, Wholfartia) ✓ Oestridae (Oestrus ovis, Dermatobia, Cordylobia, Hypoderma Gastrophilus) 4/1/22 4/1/22  Family Muscidae Musca domestica Stomoxys calcitrans Glossina palpalis (House fly) (Stable fly) Glossina morsitans (Tsetse fly) Distribution Cosmopolitan Cosmopolitan West Africa East Africa Adult: Size 7-10 mm 7-10 mm 10-15 mm Colour Grey Grey Black Brown Proboscis Sucking retractile Piercing and sucking, rigid Piercing and sucking rigid non- non-retractile. Labium swollen retractile. Labium swollen at its at its base and gradually tapers base and very thin distally having having toothed labella at its tip. labella at its tip. Thorax 4 longitudinal dark 4 longitudinal dark stripes stripes Abdomen 4 segments, median dark 4 segments, dark round spots. 8 segments, 8 segments, brown stripes. black with with yellow median pale transverse bands. stripe Notice Musca Stomoxyes DIRECT MECHANICAL INDIRECT MECHANICAL N.B.: flies are either: 1. Biting: i.e. proboscis adapted for piercing and sucking (Stomoxys and Glossina). 2. Non-biting: i.e. proboscis adapted for sucking only (all other flies).  Family Muscidae Musca domestica Stomoxys Glossina palpalis (House fly) calcitrans Glossina morsitans (Stable fly) (Tsetse fly) Egg Banana-shaped, creamy white laid in Larviparous, one at a time. batches. Breeding places Garbage and manure Horse dung Soil and Soil and open land shaded water Larva Tapering anterior and broad posterior Cylindrical with posterior knobs Posterior ends spiracles D-shape, medial button 3 M-shaped Triangular, central button 3 S- sinuous slits. shaped slits. Pupa Barrel-shaped with 2 posterior Barrel shaped knobs Medical 1-Indirect mechanical 1-Painful bites. Cyclopropagative transmission of parasitic, 2-Direct mechanical transmission of African importance viral, and bacterial transmission of trypanosomes which diseases. animal causes sleeping sickness 2-Accidental myiasis. trypanosomes. in Central Africa. The medical importance of Musca domestica (House fly): 1. Accidental myiasis: e.g. intestinal myiasis. 2. Indirect mechanical transmission of microorganisms (efficient disease agent transmitter). The tiny hair covering the body, the mouth parts, and the legs have sticky pads, all help to collect organisms from garbage and manure to human food and drink: a. Bacterial: typhoid, Shigella (bacillary dysentery) and cholera. b. Viral: trachoma, poliomyelitis, and hepatitis A. c. Parasitic: helminthic eggs and protozoal cysts. The medical importance of Stomoxys calcitrans (Stable fly): 1. Direct mechanical transmission (vector) of blood parasites e.g. Trypanosoma causing African sleeping sickness and Leishmania causing leishmaniasis. 2. Accidental myiasis. 3. Painful bites. The medical importance of Glossina species (Tsetse fly): ▪ Glossina (Tsetse) flies are the vectors (intermediate hosts) of African sleeping sickness (Trypanosoma brucei species) (biological transmission; cyclo-propagative): 1. Glossina palpalis transmits T. b. gambiense which causes Gambian sleeping sickness in Western Africa. 4/1/22 2. Glossina morsitans transmits T. b. rhodesiense which causes Rhodesian sleeping sickness in Eastern Africa.  Mechanical Musca domestica (Housefly) transmisstion Mechanical transmisstion Complete metamorphosis egg - larva - pupa - adult. Myasis Myasis They carry pathogen on their body parts and can contaminate food and contribute to the transfer of food-borne illnesses. 4/1/22 Housefly Musca domestica Proboscis Housefly Musca domestica larva (myiasis-producing) Diagnostic stage D-shape, medial button 3 M-shaped sinuous slits.  Control of housefly 1. Health education on protection and proper disposal of refuse and garbage. 2. Control measures directed against adult flies: a. Covering of house inlets and outlets by wire screens. b. Covering the food by fly nets. c. Spraying residual insecticides. d. Using traps including ultraviolet light traps 3. Control measures directed against breeding places: a. Elimination of breeding places by proper disposal of refuse and garbage. b. Sanitary disposal of excreta. c. Spraying residual insecticides especially on heaps of manure, garbage in animal- stables and slaughter houses.  Flies ❖ Class: Insecta (having a Head, Thorax, abdomen, and 3 pairs of legs) ❖ Order: Diptera (having 1 or 2 pairs of wings) ❖ Family: 4 main families of Flies ✓ Muscidae (Musca, Stomoxys, Glossina) ✓ Calliphoridae (Calliphora, Lucilia) ✓ Sarcophagidae (Sarcophaga, Wholfartia) ✓ Oestridae (Oestrus ovis, Dermatobia, Cordylobia, Hypoderma Gastrophilus) 4/1/22  Family Calliphoridae and Sarcophagidae: Calliphoridae Sarcophagidae Metallic flies Flesh flies Calliphora Lucilia Sarcophaga Wohlfahrtia Adult: Size Slightly larger than larger than Musca Musca Colour Blue Green Grey Sucking Proboscis Thorax: Shining metallic With 3 longitudinal stripes Abdomen: Shining metallic Chess board Spotted  Family Calliphoridae and Sarcophagidae: Calliphoridae Sarcophagidae Calliphora Lucilia Sarcophaga Wohlfahrtia Egg: As Musca Larviparous Larva: As Musca but larger Post. Spiracles Triangular with complete Rounded with incomplete peritreme: 3 long. slits peritreme: 3 long. slits. Habits Live on decaying animal or plant matter (Obligatory necrobiots) or invade wounds (Facultative sarcobiots). Medical Semi-specific myiasis Importance  Calliphora Lucilia blue bottle fly green bottle fly Chrysomyia Triangular with complete peritreme: 3 long. slits Larva Post. Spiracles  Wohlfahrtia Sarcophaga spotted abdomen Flesh fly Chess board Larva Post. Spiracles Rounded with incomplete Larva Post. Spiracles 4/1/22 peritreme: 3 long. slits.  ‫‪Myiasis‬‬ ‫التدويد‬ ‫الحجاج بن يوسف الثقفي‬ ‫حيث كان مرضه باألكلة وقعت في بطنه‪ ،‬ودعا بالطبيب لينظر إليها‪ ،‬فأخذ‬ ‫ما وعلقه في خيط وسرحه في حلقة وتركه ساعة‪ ،‬ثم أخرجه وقد علق‬ ‫لح ً‬ ‫به دود كثير‪.‬‬ Definition and classification of myiasis It is a condition resulting from invasion of tissues of man or animals by larval stages (maggots) of some dipterous flies (flies with 2 wings); usually occurring in tropical and subtropical areas Two methods of classification can be followed: 1. According to the biological habits of the flies: important for methods of prevention of myiasis. 2. Clinical classification according to the kind of tissues invaded 1. According to the biological habits (tissue viability) of the flies: Specific or obligatory myiasis: These fly larvae are obligatory tissue parasites. They are found only in living tissues (Obligatory Sarcobiots).  Examples: Oestrus, Cordylobia (tumbo fly limited to tropical Africa), Dermatobia and certain species of Chrysomia and Wohlfahrtia.  Cordylobia (tumbo fly) lays their eggs on the skin or the clothes and when the eggs hatch; the larvae penetrate the skin causing swellings or boils.  Dermatobia (human botfly) usually lives wildly away from man. It lays its eggs on man-visiting insects, e.g. Stomoxys, and when the latter visits man for a blood meal, the eggs hatch, and the larvae fall on the skin and penetrate it causing cutaneous myiasis.  This method of depositing eggs on a different insect for َ َ ‫َا َ ْوق ََا‬ َ ً َ َ ًَ ‫و‬ َّ ً َ ‫م َثال ما بَُو‬ َ ‫ب‬ َ ‫ر‬ ْ َ ْ ‫س َت‬ َ َّ ْ َ‫َّللا َل ي‬ َّ ِ ‫ح ِيي أن يَض‬ َ ‫ ۞ إِن‬dispersal/ transmission is known as )26( ‫البقرة‬ PHORESIS. Dermatobia life cycle Dermatobia  Semi Specific or facultative myiasis: The flies lay their eggs or larvae in decaying matter (Necrobiots) and can also attack living tissues of man and animals (Facultative Sarcobiots) e.g. Sarcophaga, Lucilia, Chrysomyia and Calliphora. Lucilia, Chrysomyia and Sarcophaga on dead bodies (Necrobiots) Forensic parasitology  Forensic parasitology Post-mortem interval (PMI) determination is useful in cases of homicide, suicide and accidental or unattended death because of natural causes. An important aspect of calculating the PMI is the accurate and quick identification of the dipteran fly collected from a crime scene. 4/1/22  Maggot Therapy Maggot Debridement Therapy (MDT)  It is a type of biotherapy or biosurgery  The used maggots are disinfected  Has been used for centuries.  American Civil War (1861-65)  Recently rediscovered and FDA-approved for use.  Usually Greenbottle flies are used.  It is used to treat diabetic foot  Acc to the habit of The fly and Tissue invaded Specific Semispecific (Obligatory Sarcobiots) (Necrobiots) Accidental On Living tissue (Facultative sarcobiots) e.g. gastric myiasis Erystalis e.g. Cutaneous myiasis Intestinal myiasis Cordylobia e.g. aural myiasis Musca Dermatobia Sarcophaga Urogenital Hypoderma Fannia  Accidental myiasis: Infection results by accidental swallowing of flies eggs or larvae or by contamination of wounds.  e.g. Musca, Stomoxys and Fannia.  Clinical classification according to the kind of tissues invaded Gastric myiasis: Eristalis -Usually the gastric juice is not suitable for larvae to remain in the stomach. -They either pass to the intestine causing intestinal myiasis or die or get vomited. e.g. Gastrophilus larvae in horses and Erystalis larva (rat-tailed larva) in man. Intestinal myiasis: -The larvae find their way to the intestine either with ingested food via mouth or through the anus during sleep or defecation in open latrines. Gastrophilus -Symptoms and signs vary according to the number of larvae; but mainly: nausea, vomiting and abdominal discomfort or pain with diarrhea. Living or dead larvae may be found in stools or vomitus and can be diagnosed by their posterior respiratory spiracles 4/1/22 e.g. Calliphora, Lucilia, Musca and Sarcophaga.  Urogenital myiasis: Probably during sleep or during defecation, certain flies deposit their eggs on the urethral opening. When the larvae hatch, they creep up the urethra to the bladder Fannia larva and the urinary tract. In female patients, the larvae may go to the vagina. There may be symptoms of obstruction to urine with pain or inflammation with pus, mucus and blood in urine. Some larvae may pass with urine. e.g. Fannia (latrine fly). 4/1/22  Cutaneous myiasis: Creeping eruption: Larvae of Hypoderma parasitize some animals. When accidentally they find their way to the skin of man, they go on wandering in the dermal layer incapable of proceeding further, causing certain papules and pustules. This is called creeping eruption or larva migrans. hypoderma Furuncular or nodular myiasis by dermatobia and cordylobia Traumatic dermal myiasis, where wounds or ulcers are invaded by larvae, causes serious damage. e.g. Wohlfahrtia, Calliphora, Sarcophaga and Chrysomia. Cutaneous myiasis due to Dermatobia (human botfly) 4/1/22 Case study: Fruncular or nodular myiasis A 65-year-old man presented with skin lesions on his chest and left arm and shoulder six weeks after returning from a vacation in Belize at the beach and in the rain forest. The lesions occasionally stung, drained a dark exudate, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination -revealed five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed (Panel A). -The pores were occluded with petrolatum for two hours. After lidocaine was injected around the nodules, five Dermatobia hominis larvae at various developmental stages were extracted with the use of manual pressure and tweezers 4/1/22 (Panel B). Case report A 52-year-old male weighing 45 kg was admitted to a hospital in Montes Claros, Minas Gerais, Brazil via the emergency room. Montes Claros is a mid-sized city in the interior of Brazil that serves as the center for medical treatment to a large  The emergency room diagnosis was a severe case of surrounding rural population. The patient myiasis infestation. Clinical examination revealed edema of the upper lip with a small opening lived in a rural area and had been admitted (required for the larvae to breathe). The patient to the same hospital with a diagnosis of reported the sensation of things moving inside the Alzheimer’s disease 5 years earlier. He had swollen area. After local anesthesia at the site of not received specialized medical treatment infection, an incision was made in the upper lip and for Alzheimer’s since that time. Patients the larvae were removed surgically. Two 6 mg ivermectin tablets were prescribed. Following the who suffer from Alzheimer’s disease are procedure the patient was hospitalized for medical generally dependent on assistance from care to address his underlying poor health (primarily family members to maintain their overall severe under-nutrition). The larvae were health, including oral hygiene. subsequently submitted for parasitology4/1/22testing which reported them to be D. hominis.  Furuncular myiasis due to cordylobia A 46-year-old woman returned from a trip to A Nigeria with multiple boils on her lower back and extremities. Under the care of her primary physician, several fly larvae, one from each boil, were extracted and sent to the state health department for identification. The specimens were in turn forwarded to the CDC-DPDx for further B diagnostic assistance. Figure A shows two of the larvae; Figure B shows a close-up of the posterior spiracles of one of the specimens. What is your identification? Based on what criteria? 4/1/22  Atrial myiasis Oral myiasis Aural myiasis: - Purulent discharge from ears attracts several Aural myiasis: species of flies to lay their eggs or larvae. Then the larvae invade the middle or inner ear or even mastoid sinuses and the brain tissues e.g. Wohlfahrtia and Sarcophaga. Nasopharyngeal myiasis through tracheostomy Ocular and nasopharyngeal myiasis: tube - The larvae of flies find their way to the conjunctiva or nose. They may cause serious damage destroying the eyes, orbit or even the sinuses and may reach the brain with fatal results e.g. Wohlfahrtia and Sarcophaga.  Oestrus ovis Oral myiasis caused by O. ovis in Iran.  Orbital Myiasis: Due to Invasion of Larvae of Flesh Fly (Wohlfahrtia) in a Child -Wohlfahrtia larvae cause myiasis in mammals, mainly in sheep and rarely in human. -In human it may infest the ear, eye, mouth or nose, damaging living tissues.  Treatment:  Mechanical removal of the maggots was done with the help of forceps after immobilizing the larvae by applying 4% xylocaine and mixture of chloroform plus turpentine oil packing. ocular myiasis due to Wohlfahrtia magnifica  Regular dressing and removal of maggots was done for five days. larvae in 1.5 years old child belonging to urban  Routine topical and systemic antibiotics along with anti- inflammatories were administered. The ulcer healed within slum after history of two weeks. minor injury on left upper  Thirty-five larvae were removed and preserved in diluted lid due to fall from bed. 4/1/22 formalin and were examined later on by an entomologist and identified as larvae of flesh flies Diagnosis This is based on the isolation and identification of larvae from tissues or discharge. -Larvae are identified by their shape and the pattern of posterior spiracles, which are characteristic for each group of flies. 4/1/22  Treatment:  lntestinal and gastric myiasis: purgation with sodium sulphates.  Urinary myiasis: if the condition does not end spontaneously, the larvae need to be removed by cystoscopy.  Cutaneous, ophthalmic, aural and nasopharyngeal myiasis: Surgical removal of the larvae and cleanlining of the affected part is usually needed.  Ivermectin is given: 2 tablets 6 mg each Prevention of myiasis 1-Control or eradication of the fly population - through environmental sanitation or chemical control. 2- Good hygiene especially of old people and children with special needs 3-clean wound and close it with surgical dressing 4- protection of food from flies 5-protection of human especially children by nets 6- Sterilization of males by radiation eradicate it from North America 3-What is the larva revealed by urine examination of a myiasis patient who frequently uses public toilets (latrines)? A. Sarcophaga species B. Dermatobia species C. Chrysomia species D. Fannia species 4- What is your diagnosis if larvae with open peritreme isolated from the tracheostomy tube in an old man living in a rural area? a. Calliphora b. Musca c. Sarcophaga d. Dermatobia