Flies PDF - Introduction to Medical Entomology MDU 1043

Introduction to Medical Entomology MDU 1043 Suborder Cyclorrhapa Family Muscidae (house flies, greater house flies, stable flies) 2023/2024 Session, Semester 2 A/P Dr. Nor Aliza Abdul Rahim  Objectives: Describe the Family Muscidae. D...

Introduction to Medical Entomology MDU 1043 Suborder Cyclorrhapa Family Muscidae (house flies, greater house flies, stable flies) 2023/2024 Session, Semester 2 A/P Dr. Nor Aliza Abdul Rahim  Objectives: Describe the Family Muscidae. Describe the morphology and life cycle of the Family Muscidae. Discuss the medical importance of the Family Muscidae Explain the control methods for the Family Muscidae.  Outline of Lecture: Introduction to Family Muscidae. Morphology and life cycle of a house fly, greater house fly and stable fly. Medical importance of house flies, greater house fly and stable fly. Control methods for house-flies, greater house fly and stable fly.  Family Muscidae Introduction: Family Muscidae is in the suborder Cyclorrapha, order Diptera There are about 4200 species and 170 genera. Three medically important species are: 1) Musca domestica (house-fly) 2) Muscina stabulans (greater house-fly) 3) Stomoxy calcitrans (stable-fly) Their distribution are worldwide. House-flies can vector pathogens and stable-flies can cause biting nuisance. Greater house fly may also vector pathogens. Musca domestica Muscina stabulans (house fly) (greater house fly Stomoxy calcitrans (stable fly)  Musca sp. Introduction: There are about 70 species of the genus Musca. Musca domestica is the most important and has a worldwide distribution. Other important Musca sp. are: 1) Musca sorbens (bazaar-fly), a nuisance in Africa, Asia and the Pacific. 2) M. vetustissima (bush-fly), in Australia 3) M. autumnalis (face-fly), pest worldwide  Musca domestica (house-flies) Morphology: Medium size, non-metallic, 6-9mm long Color vary from black to dark grey Has four broad black longitudinal stripes on the thorax. Antennae is concealed on the front face. It has 3 segments. The distal part of the antenna has prominent hair known as arista.  Musca domestica (house-flies) The proboscis consists of labella and pseudotrachaea that are adapted for sucking fluid. For dried food, the flies moisten the food with their saliva or regurgitate the food before sucking it (this method allows the spread of pathogens)  Musca domestica (house-flies) Morphology: One of the major characteristic of Musca species is seen in the wing venation. House-fly vein 4 bending sharply towards vein 3. 1 2 3 4  Musca domestica (house-flies) All legs of house-fly has a pair of claws, fleshy pad (pulvilli) and a bristle (empodium) Pulvilli (pad) has many glandular hairs which pick up pathogens when fly lands on feces, rubbish and other contaminated substances. empodium  Musca domestica (house-flies) Life cycle: House-flies lay eggs on decomposing materials (animal manure, poultry dung, carcasses, rubbish dumps, garbage, etc) 75-150 eggs are laid and one female can oviposit 5-10 times during its life. Eggs are creamy white, banana shaped, hatch after 10-16 hours. The eggs cannot tolerate desiccation and extreme temperatures.  Musca domestica (house-flies) Life cycle: The larva known as maggots has cylindrical body. The head contain hooks and cephalopharyngeal skeleton. The posterior end has a D-shaped spiracles for breathing and a peritreme surrounding it. The larvae feed on decomposing organic material. A mature larvae measure between 8-14mm long. Before becoming a pupa, it will move to a drier place or into the dry soil. Spiracles Head with hooks  Musca domestica (house-flies) Life cycle: After migration into soil or to a drier spots, the larvae skin become harden and turn dark brown. The house-fly pupa or puparium is barrel-shaped. After 3-5 days in a warmer area, the pupa will become adult fly.  Musca domestica (house-flies) The adult fly escape form the puparial case by pushing its anterior end and crawling out. Adult house-flies prefer buildings with animals or people in it. This is known as domestic or synantrophic flies. They can fly between 1-5 km from their breeding site. Musca domestica (house-flies) life cycle  Medical importance of house-flies House-flies can transmit pathogens to human because of their habits of visiting unhygienic matter and then to humans’ food. Pathogen can be transmitted through 3 possible routes: 1) By flies’ contaminated feet, body hairs and mouthparts (known as mechanical transmission). 2) By flies vomiting on food during feeding 3) By defecation on food  Medical importance of house-flies Over 100 pathogens recorded from house-flies and 65 are transmitted to people. Among pathogens transmitted are: 1) viruses: polio, Coxsackie, hepatitis 2) bacteria: anthrax, cholera, Shigella, Salmonella, E.coli 3) protozoans: Entamoeba, Cryptosporidium, Giardia 4) eggs of helminths: Enterobius, Trichuris, Ascaris 5) eyeworm (Thelazia sp.) Eyeworm  Medical importance of house-flies House-fly can carry egg of Dermatobia hominis (bot fly) causing myiasis. Evidence that house fly cause ill-health through transmission of pathogen: 1) A study in two Texan town where there were diarrheal disease due to Shigella sp. in 1946 and 1947. One town was sprayed with DDT to reduced house-flies population and the other was not. The sprayed town showed reduction and the other town remain the same. When the sprayed activity was reversed, the cases of diarrhea was also reversed.  Medical importance of house-flies Evidence that house fly cause ill-health through transmission of pathogen: 2) In 1988 at an Israeli army camp, control of house-flies using attractant traps showed reduced bacteria infection: Shigella and E. coli. 3) In 1995 and 1996, when a breeding site of Pakistani villages was sprayed with insecticide, 95% of flies was reduced and consequently the incidence of childhood diarrhea was reduced by 23%.  Control of house-flies Control methods for house-flies are divided into three categories: 1)Physical and mechanical control 2)Environmental sanitation 3) Insecticidal control Physical and mechanical control includes: i) Installing a screening on windows and other openings. ii) Using air currents or fans or curtain strips at the premises entrance to keep flies from entering. iii) Use of ultraviolet light traps. iv) Use of sticky traps PVC strip Window netting  Control of house-flies Control methods for house-flies are divided into there categories: 1)Physical and mechanical control 2)Environmental sanitation 3) Insecticidal control Environmental sanitation aims to reduce house-fly population by minimizing their breeding sites. This includes: i) Garbage need to be tightly closed to prevent flies from laying eggs. ii) Garbage need to be collected regularly. iii) If not, garbage need to be burnt or buried.  Control of house-flies Control methods for house-flies are divided into there categories: 1)Physical and mechanical control 2)Environmental sanitation 3) Insecticidal control Insecticidal control is the use of chemical to control the population of house-flies. House- flies developed resistance very quickly therefore use of insecticide must be properly regulated. There are several methods used: i) Larvicides ii) Adulticides iii) Residual spraying iv) Insecticidal cords v) Toxic baits  Control of house-flies Insecticidal control: i) Larvicides- spraying breeding sites of house-flies with insect growth regulators (IGRs) eg: diflubenzuron, cryomazine and pyriproxyfen. IGRs stop the growth of house-flies larvae so they are unable to molt to the next stage.  Control of house-flies Insecticidal control: ii) Adulticides- Indoor control of the adults is by using commercial aerosol sprayers to immediately kill the adult flies. Insecticides used includes malathion, pirimiphos-methyl, fenchchlorophos, permethrin, cypermethrin and deltamethrin.  Control of house-flies Insecticidal control: ii) Adulticides- Outdoor control is by using ULV spraying with pyrethroids over areas like farms, markets and recreational areas. 23 June 2011- Flies problems in poultry farm in Negeri Sembilan Flies control and flies larva control test trial is carried out in a poultry farm at Negeri Sembilan. We have been asked to train the poultry farmer using SCEA Pesguard 161 to fog the flies. After a few space treatment fly population had reduced tremendously and to control fly larvae the same process is necessary. X-way Sdn Bhd news  Control of house-flies Insecticidal control: iii) Residual spraying- spraying indoor walls , ceiling and doors with eg: malathion, fentrothion or pirimphos- methyl, cypermethrin, deltamethrin and permethrin. Residual insecticides can remain active between 1-2 months.  Control of house-flies Insecticidal control: iv) Insecticidal cords- cords or rope strips soaked with insecticides eg: diazinon, dimethoate, malathion, propoxur, cypermethrin or permethrin, and a red dye to alert people. Usually hang in premises or dairy farms shed and can be effective for 2-6 months. Strips or cords of cotton, cloth or gauze impregnated with a long-lasting insecticide can easily be suspended from ceilings  Control of house-flies v) Toxic baits- Dry baits contain sugar mixed with bran and corncobs treated with insecticides. These can be scattered on the floors or in trays and placed in places infested with flies. It contains both a feed attractant and a sex attractant Tricosene.04% and Methomyl 1%. It can be used around dumpsters, outside around restaurants, and outside houses where children and pets cannot eat the bait.  Control of house-flies v) Toxic baits- Liquid bait consist of sugar solution and insecticides placed in a bottle or saucer, and let evaporate into the air of the area. The lure (sugar solution) will attract flies into the bait and flies will be killed by the insecticide in the solution. a reusable plastic quart jar that comes with a packet of lure and holds 5,000 dead flies  Liquid bait fly trap Fly bait card  Muscina stabulans (greater house fly) Introduction: Muscina stabulans is distributed worldwide. Slightly larger than Musca domestica (7-10mm long) Also known as false stable fly. Wing venation slightly differ to house fly (vein 4 slightly bended toward vein 3)  Muscina stabulans (greater house fly) Posterior spiracles of the maggot is circular (Its D-shaped in Musca domestica) Peritreme is very thick and completely encircle the spiracular slits. The late larval stage (maggots) are predaceous and feed on other fly larvae. Life cycle is very similar to Musca domestica Their medical importance and control methods are also similar to Musca domestica. M. stabulans spiracles M. stabulans maggot  Stomoxy calcitrans (stable fly) Stable flies are distributed worldwide. Also known as biting-house flies or dog flies. Adults has four longitudinal stripes on thorax. Their size and looks resembles house fly. They differ from house flies and greater house flies greatly because they posses conspicuous forward-projecting, rigid proboscis Forward-projecting rigid proboscis Stomoxy calcitrans  Stomoxy calcitrans (stable fly) Their wing venation resembles Muscina but the arista of stable fly antenna has hairs only on the upper side which differ from Musca domestica and Muscina calcitrans. Wing venation of stable fly  Stomoxy calcitrans medical importance Both male and female stable flies feed on blood. They blood feed on domesticated animals such as cattle and horses, pigs and dog, and also on human. Biting and blood feeding only occur during daytime. Stable flies are mainly exophagic. They are also known to carry Dermatobia hominis eggs, a myiasis-producing fly.  Stomoxy calcitrans control methods Stable fly maggots develop in decaying organic matter such as fermented mixture of straw, hay, urine or moist environment. Control methods of stable flies are similar to house flies. Mainly insecticides eg; permethrin are sprayed at horse stables, animal shelters, barns and other farm buildings. Fly traps are also used to reduce fly populations. End of Lecture! Introduction to Medical Entomology MDU 1043 Family Calliphoridae 2023/2024 Session, Semester 2 A/P Dr. Nor Aliza Abdul Rahim  Objectives: Describe the Family Calliphoridae. List the medically important species in the Family Calliphoridae Discuss  their biology and medical importance  their distribution.  the control methods against them  Outline of Lecture: Family Calliphoridae Medically important species in the Family Calliphoridae. Life cycle and medical importance of Family Calliphoridae Distribution of Family Calliphoridae Control methods against Family Calliphoridae  Subphylum Uniramia Class Insecta Order Diptera circular-seamed flies, Suborder Cyclorrhapha aristate antennae Muscidae Calliphoridae (blow flies) Sarcophagidae Oestridae Glossinidae (house flies, Cordylobia anthrophophaga (flesh flies) (bot flies) (tsetse flies) stable flies) Cochliomya hominivorax Sarcophaga sp. Dermatobia hominis Glossina morsitans Musca domestica Chrysomya bezziana Wohlfahrtia sp. Glossina palpalis Muscina stabulans Lucilia sp. Stomoxy Calliphora sp. calcitrans Myiasis causing flies  Family Calliphoridae Family Calliphoridae consist of flies under the suborder Cyclorrhapa (cyclor means circular and rhapha means seam) They are circular-seamed flies with aristate antennae Circular seamed: the adults exit their puparium through a special end cap surrounded by a weakened circular seam. They are medically important mainly due to its capability in producing myiasis Circular-seamed on pupa casing Aristate antennae  Family Calliphoridae Introduction to medically important species: Two groups of calliphorids: non-metallic and metallic flies. Non-metallic flies: Cordylobia anthropophaga Metallic flies (blowflies): Cochliomyia spp. (New world screwworms) Chrysomya spp. (Old world screwworms) Lucilia spp. (greenbottle flies) Calliphora spp. (bluebottle flies)  Family Calliphoridae: Cordylobia anthropophaga Non-metallic flies: Cordylobia anthropophaga (tumbu or mango fly) Distribution: Ethiopia, west, east and south of Africa Large flies (9-12mm long), dull to yellowish brown in color  Family Calliphoridae: Cordylobia anthropophaga Non-metallic flies: Cordylobia anthropophaga (tumbu or mango fly) Myiasis causing fly Female lays 100-300 banana-shaped eggs in feces/urine contaminated areas Hatch larva can live 9-15 days without hosts Larva attach to host or to clothing laid on ground. Larva burrow into skin, posterior spiracles exposed for breathing. Matured after 8-12 days and drop to the ground to pupate Become adult after 8-15 days. Tumbu fly life cycle Adult Eggs Larva 3-instars Pupa  Tumbu fly larva Tumbu fly adult Tumbu fly pupal casing  Family Calliphoridae: Cordylobia anthropophaga Medical importance of Cordylobia anthropophaga (tumbu or mango fly) The larva cause boil-like (furuncular) swellings on body Infested site become sore, inflamed, hard and exude fluids Infestation usually with few larvae and up to 60 larvae The larva head and body are in tissues The spiracles are exposed for breathing  Family Calliphoridae: Cordylobia anthropophaga Removal of larvae by covering the site with liquid paraffin or Vaseline. Larva will emerge from the site to breathe then it can be removed with forceps or by pressing Family Calliphoridae: Cordylobia anthropophaga Before and after tumbu fly removal  Family Calliphoridae: Cordylobia anthropophaga To prevent infection by tumbu fly maggot, avoid drying clothes on ground where the larva can attached Iron clothes to ensure no living larva on clothes.  Family Calliphoridae Metallic flies: Cochliomyia hominivorax (New world screwworm) Chrysomya bezziana (Old world screwworm) Lucilia spp. (greenbottle flies) Calliphora spp. (bluebottle flies) Cochliomyia hominivorax used to occur in south USA, Mexico, Central America, Caribbeans and north part of South America. Eradication program has successfully eradicate Cochliomyia from USA, Mexico, the Virgin island, Curacao and Central America (except Panama) Cochliomyia hominivorax is an obligatory parasites of living tissues (must have host to survive)  Family Calliphoridae Metallic flies: Chrysomya bezziana (Old world screwworm) Chrysomya spp. has 10 species that can cause myasis Chrysomya bezziana is the most important. It is an obligatory parasites of living tissues (must have host to survive). It is distributed through tropical Africa, west coast of Persian Gulf, Indian subcontinent, Southeast Asia to China and Papua New Guinea  Family Calliphoridae Distribution of Old and New world screwworms Old world screwworm New world screwworm  Family Calliphoridae Cochliomyia homnivorax Adult- 8-10mm long, metallic green and bluish green Have 3 longitudinal stripes on thorax  Family Calliphoridae Cochliomyia homnivorax Life cycle and biology Adult female can lay 10-200 eggs on wounds or scratches, dried blood clots and on mucous (nasal, eyes, ears, mouth and vagina) Larva (maggot) emerged after 10-24 hours and burrow deep in tissues and feed. After 2-4 days, larva reached 3rd instars After 4-10 days, larva matured and leave the wound and drop to the ground to become pupa Adult emerge after 7-10 days (warm weather) or weeks to months in cooler climate  Family Calliphoridae Cochliomyia homnivorax  Family Calliphoridae Life cycle of a screwworm fly  Family Calliphoridae Cochliomyia homnivorax Maggot or larva of NW screwworm, whitish in color NW screwworm has hooks on the mouthpart to hold NW screwworm to host tissues pupa with hard pupal skin  Family Calliphoridae Chrysomya bezziana Larva of Chrysomya bezziana, Similar to C. hominivorax. Adult of Chrysomya bezziana, Differences is at the spiracles Lacks of longitudinal thoracic stripes morphology The life cycle of C. bezziana is similar to C. hominivorax  Family Calliphoridae Screwworm infestation: myiasis Medical importance of New world and Old world screwworms (Cochliomyia homonivorax and Chrysomiya bezziana) Myiasis  Family Calliphoridae Screwworm infestation: myiasis Both C. hominivorax and C. bezziana cause obligatory myiasis. Infestation with screwworms cause damage and disfigurement especially if face is involved. Infestation also cause excruciating pain and misery, destruction and ulcerations with putrid smelling discharges Infestation of the nasal area can affect mouth palate and impair speech due to their feeding on tissues  Family Calliphoridae Screwworm infestation: myiasis 9-year-old boy from a border town with Kalimantan Myiasis in the eye with previous ear myiasis Site of maggot infestation Tissue of the conjunctiva was incised to allow removal of maggot with forceps 12 cm maggot removed  Family Calliphoridae Screwworm infestation: myiasis Myiasis in the ear spiracles Screwworms Screwworm embedded in tissues in the ear  Family Calliphoridae Screwworm infestation: myiasis An 86-year-old woman Myiasis in the foot between toes A 74-year-old, nondiabetic man Myiasis on bunion  Family Calliphoridae Screwworm infestation: myiasis Myiasis treatment: Must be treated immediately because larva develop rapidly Maggots or larva must be removed manually The wound sites should be irrigated with ethanol or chloroform mixed with vegetable oil. Ivermectin can be use to kill the larvae For deeply embedded larva, surgery is needed  Family Calliphoridae Screwworm fly control and prevention: Prevention of infestation is by using topical repellents and proper clothing for personal protection. Maintain self hygiene Must create barrier, like house screening to prevent fly from entering home. Adopting to houseflies control methods is recommended Eradicating of screwworm flies using sterile male technique was successful in USA and Mexico To be continued…  Family Calliphoridae Metallic flies (blowflies): Cochliomyia spp. (New world screwworms) Chrysomya spp. (Old world screwworms) Lucilia spp. (greenbottle flies) Calliphora spp. (bluebottle flies) Lucilia spp. (greenbottle flies) Another name is Phaenicia spp. Lucilia serricata is the most common species occurring worldwide. Lucilia cuprina occurs mainly in Africa, Asia and Australia. Calliphora spp. (bluebottles flies) Found worldwide but more commonly in temperate regions. Important species causing myasis are Calliphora vicinia and C. vomitoria.  Family Calliphoridae Lucilia spp. (greenbottle flies) Adult are metallic or coppery green in color Size ~ 10mm long Less bristly than bluebottle flies Lucilia sp. Lucilia serricata Lucilia cuprina  Family Calliphoridae Calliphora spp. (bluebottles flies) Adults are dull metallic bluish or bluish black in color Calliphora are robust flies with size~ 8-14mm long Thorax has a more well-developed bristles than Lucilia spp. Abdomen is more shiny than thorax Calliphora vomitoria Calliphora vicinia  Family Calliphoridae Greenbottle and bluebottle flies lay eggs on meat, fish, carrion, decomposing carcasses, excreta and decaying vegetables. Occasionally lay eggs on foul-smelling wounds of animals or human. The adult are common near slaughterhouses and pig farms Adult fly with annoying noisy buzzing flight sounds. Control measures of Lucilia sp. and Calliphora sp. are the same as in control for houseflies and blowflies. Lucilia serricata on dog feces Life cycle of Calliphora is very similar to Lucilia  Family Calliphoridae Medical importance of Lucilia sp. and Calliphora sp. Both are associated with facultative myiasis (can live on their own if there is no host). They are attracted to foul-smelling wounds and ulcerations (with pus) Because of this behaviour, these species are used in maggot therapy.  Maggot therapy Maggots in biobag Maggots applied to wounds Wound healing through maggot therapy End of Calliphoridae lecture Introduction to Medical Entomology MDU 1043 Suborder Cyclorrhapa Family Oestridae (human bot flies) 2023/2024 Session, Semester 2 A/P Dr. Nor Aliza Abdul Rahim  Objectives: Describe the Family Oestridae. List the medically important species in the Family Oestridae Discuss  the disease they cause in human  the disease distribution.  the treatment and prevention  Outline of Lecture: Family Oestridae. Medically important species in the Family Oestridae. Diseases caused by Family Oestridae in human. Distribution of human bot fly. Treatment and prevention from human bot fly infestation  Subphylum Uniramia Class Insecta Order Diptera circular-seamed flies, Suborder Cyclorrhapha aristate antennae Muscidae Calliphoridae (blow flies) Sarcophagidae Oestridae Glossinidae (house flies, Cordylobia anthrophophaga (flesh flies) (bot flies) (tsetse flies) stable flies) Cochliomya hominivorax Sarcophaga sp. Dermatobia hominis Glossina morsitans Musca domestica Chrysomya bezziana Wohlfahrtia sp. Glossina palpalis Muscina stabulans Lucilia sp. Stomoxy Calliphora sp. calcitrans Myiasis causing flies  Family Oestridae Introduction: There are four subfamilies : Oestrinae, Gasterophilinae, Hypodermatinae and Cuterebrinae. Subfamily Cuterebrinae contains 57 species that cause obligatory myiasis in animals such as rodents, monkeys, livestocks and human. The species that cause myiasis in human is Dermatobia hominis. Life cycle of Dermatobia hominis Life cycle of Dermatobia hominis  Dematobia hominis Psorophora sp. The botfly Dematobia hominis can infest human and cause a condition called myiasis. Myiasis is the invasion of organs and tissues of human or animals by fly larvae. The larvae feed on the living or dead tissues of the host. Many other larva (maggots) of fly species can also cause myiasis. The flies that cause myiasis are found worldwide and infest many animals as well as humans. Human infestation occurs most often in tropical areas.  Dermatobia transmission Route of transmission varies depending on the species of fly. Adult fly can deposits eggs at several body sites and larva will hatch and infest the sites. The sites can be: wound, nostrils, conjunctiva, or lips. Certain adult fly deposits the egg on unbroken skin and the larva invades the skin. Dermatobia can also deposits its egg on a mosquito. When the mosquito bites a human, the warmth of the skin induces the egg to hatch and the larva enters the skin at the site of the mosquito bite. Family Oestridae The presence of the larva in tissue induces an inflammatory response. The characteristic lesion is a painful and swollen skin known as cutaneous myiasis. The larva can often be seen at the center of the pore and some patients report a sense of movement within the lesion. Commonly patients has a history of travel to tropical regions.  Dematobia hominis mouth hooks Dematobia hominis spiracles Dematobia hominis larvae emerging Dematobia hominis larvae from a lesion.  Family Oestridae Treatment Surgical removal of the larva is the most common mode of treatment. If the larva is visible, manual extraction can be performed. If the larva is not visible, the central pore can be covered with petroleum jelly thus causing hypoxia in the larva. This induces the larva to migrate to the surface.  Family Oestridae Prevention Limit exposure to flies, especially in tropical areas. General measures, such as wearing clothing that covers the extremities. Use mosquito netting when sleeping. Use of insect repellant on exposed skin are recommended A cow infested with Dematobia hominis Dematobia hominis adult emerging from pupal skin Lecture Ends Here! Introduction to Medical Entomology MDU 1043 Suborder Cyclorrhapa Family Sarcophagidae (flesh flies) 2023/2024 Session, Semester 2 A/P Dr. Nor Aliza Abdul Rahim  Objectives: Describe the Family Sarcophagidae. List the medically important species in the Family Sarcophagidae Discuss  the disease they cause in human  the disease distribution.  the treatment and prevention  Outline of Lecture: Family Sarcophagidae. Medically important species in the Family Sarcophagidae. Diseases caused by Family Sarcophagidae in human. Distribution of flesh fly. Treatment and prevention from flesh fly infestation  Subphylum Uniramia Class Insecta Order Diptera circular-seamed flies, Suborder Cyclorrhapha aristate antennae Muscidae Calliphoridae (blow flies) Sarcophagidae Oestridae Glossinidae (house flies, Cordylobia anthrophophaga (flesh flies) (bot flies) (tsetse flies) stable flies) Cochliomya hominivorax Sarcophaga sp. Dermatobia hominis Glossina morsitans Musca domestica Chrysomya bezziana Wohlfahrtia sp. Glossina palpalis Muscina stabulans Lucilia sp. Stomoxy Calliphora sp. calcitrans Myiasis causing flies  Family Sarcophagidae Introduction: Only two genus of Sarcophagidae that are medically important: Sarcophaga sp Wohlfahrtia sp. They cause myiasis and act as mechanical vector for pathogens. They are distributed worldwide Wohlfahrtia sp Sarcophaga sp  Family Sarcophagidae Sarcophaga sp. Large greyish flies (10-25mm) with hairy and non-metallic appearance Has 3 black longitudinal stripes on thorax Has chequer-board appearance on the abdomen The female do not lay eggs. They are larviparous (deposits first-instar larvae) ~ 30-60 per batch Larvae are laid on carcasses, feces, rotting food, human and wounds Before pupating, they migrate to soil and become adult after 7-12 days Sarcophaga sp  Family Sarcophagidae Sarcophaga sp. medical importance When the larvae are on wounds, they feed on necrotic tissues causing facultative myiasis. Certain species (S. haemorrhoidalis) cause accidental intestinal myiasis. The myiasis cause discomfort and pain until the larvae are expelled in the feces. The species causing accidental intestinal myiasis are distributed in the Americas, Europe, Africa and Asia  Family Sarcophagidae Wohlfahrtia sp. Adults Wohlfarhtia sp. are hairy flies which are smaller (8- 15mm) than Sarcophaga sp. The appearance is greyish with prominent black lines on the thorax which is similar to Sarcophaga sp. However, Wohlfahrtia sp. abdomen has roundish lateral spots and triangular shape markings along midline. Wohlfarhtia magnifica  Family Sarcophagidae Wohlfahrtia sp. Adult female are larviparous and can deposit 120-170 larvae in several batches on wounds, scratches, sores and ulcerations. Larvae are also deposited in ears, eyes, nose which can cause deafness, blindness and death. Wohlfarhtia larvae look very similar to Sarcophaga larvae. Larva takes 5-9 days to develop into pupa. Mature larvae will drop and burrow into the ground and pupate. Pupa require between 8-12 days to become adults. Wohlfahrtia larva  Family Sarcophagidae medical importance Wohlfahrtia sp. W. magnifica is an important species in the Old World which cause obligatory myiasis in human and animals. This species is predominant in western Europe, the Middle east, North Africa and Central Asia to China. W. vigil and W. opaca, New World species, prefer soft skin and attack babies and young children. These species cause furuncular myiasis (bite-like lesion that progress into enlarged pruiritic nodules). Wohlfahrtia larvae can burrow deep into tissues and cause considerable damage to the infested person. Orbital Myiasis: Due to Invasion of Larvae of Flesh Fly (Wohlfahrtia magnifica) in a Child; Rare Presentation Maurya et al. 2012, Case reports in ophthalmological medicine DOI:10.1155/2012/371498 Wohlfahrtia magnifica 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. We report a case of ocular myiasis in 1.5 years old child belonging to urban slum after history of minor injury on left upper lid due to fall from bed. The purpose of reporting this case is to highlight the ocular association of W. magnifica. Maggots removed from the eyelid The same child after treatment Myiasis  Myiasis Myiasis is invasion of organs and tissues of living human or other vertebrate animals by fly larvae (maggots), which feed on the living or dead tissues.  Myiasis Types of myiasis Accidental myiasis: myiasis due to accidentally ingesting food that is contaminated with eggs or larvae of flies. The presence of larvae cause discomfort, abdominal pain and diarrhea accompanied by discharge of blood and vomiting. Obligatory myiasis: when fly larvae must live on living host at least part of their lifecycle. Examples are Wohlfahrtia magnifica and Dermatobia hominis. Facultative myiasis: fly larvae are normally free-living and usually feed on carcasses, but under certain conditions may infect living host such as on sores or wounds. Examples are Sarcophaga, Calliphora and Lucilia  Myiasis Terms of myiasis (based on parts of body that are affected) Cutaneous, dermal and subdermal myiasis: pertaining to skin and tissue layers underneath it Opthalmic or ocular myiasis: pertaining to the eyes Urogenital myiasis: pertaining to the genital and urinary Nasopharangeal myiasis: pertaining to the nose or nasal area Intestinal myiasis: pertaining to the intestine Furuncular myiasis: myiasis with boil-like lesion Traumatic myiasis: wounds that are heavily infested with larvae  Treatment of Myiasis Occlusive and Suffocation methods Applies liquid paraffin or petroleum jelly on the affected area on your skin. This prevents oxygen from reaching the larva and as a result, the larva would get out of the body by itself. Surgery Surgery is by removing the fly larvae from the affected area. Medication Specific medication depending the form of myiasis. The drugs recommended include drug ivermectin to treat orbital and oral myiasis  Prevention of Myiasis Use insect repellent to prevent insects from moving into the house. Spray around the affected area using insecticides that has organophosphorus to destroy larvae. Use mosquito nets and wind screens to prevent insect from moving into the house. If you have a wound, always cover it with a bandage to protect yourself from infection. Iron clothing that are hanged outside before putting them on to kill any insect affixed on them Maintain high levels of hygiene: wash clothes regularly and wash hands properly before you eat and after you have finished eating; dry clothes under the direct sun. (https://hipatient.com/myiasis-oral-cutaneous-definition- treatment-pics) Lecture Ends Here! Introduction to Medical Entomology MDU 1043 Family Glossinidae (Tsetse Flies) Session 2023/2024 15 May 2024 Dr Khatijah Yaman Outline of Lecture Family Glossinidae Medically important species Diseases caused in human Mode of transmission and distribution of disease vector Control methods Family Glossinidae (Tsetse Flies). Family Glossinidae (Tsetse Flies). Glossina is the only genus in the family of Glossinidae. There are 23 species, 6 of them are divided into 2 or more subspecies. Most of them are restrictedly found in sub-Saharan Africa, only 2 species are found in south-west Arabia. Distribution of Glossina morsitans: across West Africa to Central and East Africa. Others are more limited in their distribution e.g. G. palpalis occurs only in the West African subregion. They are vectors for both human and animal African trypanosomiasis, also known as sleeping sickness. Important vectors are G. palpalis, G. tachinoides, G. fuscipes, G. pallides and G. morsitans.  Family Glossinidae (Tsetse Flies). They are 6-14mm in size. Adults are yellowish to brown-black robust flies. Distinctly different from other flies by the combination of a rigid forward-projecting proboscis and a closed cell between wing veins 4 and 5 (hatchet cell). At rest tsetse flies placed their wings over the abdomen like closed blades of a pair of scissors. Their proboscis are large and has a bulbous base. Distinctly different from other flies when feeding i.e. Proboscis is swung downwards while the palps remain projecting forward. Dorsally the thorax has dark brown stripes or patches. Both sexes take blood meals  Male vs Female Glossina sp Comparison of ventral side of male and female Tsetse flies (Glossina morsitans morsitans) The male (left) has a longer, narrower abdomen, while the female's abdomen is shorter and fatter. Both sexes feed exclusively on blood. Alimentary canal of adult fly Glossina sp: The Life-cycle  Glossina sp: The Life-cycle After females have mated and taken blood meal, a single egg in one of the 2 ovaries complete maturation. It passes down the common oviduct into the uterus, where it fertilised by sperm from paired spermathecae. Egg hatches within the uterus after 3-4 days into larvae. Secretion from milk glands provide larva with all the nutrients for growth and development – 3 instars in the female. Larval development takes about 9 days. Female select shaded sites for larviposition. About 15 min, 3rd instar larval skin contracts and harden to form puparium, in which larvae pupate. Puparial period is about 4-5 weeks. 1st larva deposited about 16-20 days after the female has emerged from puparium, if food is plentiful, a larva is deposited about every 9-12 days.  Glossina sp: The Life-cycle Adult behaviour: Feed depending on host availability. Blood feed about every 2-3 days. In cool humid conditions, feed about every 10 days. Feeding restricted in daytime and vision, as well olfactory cues emanating from host breath and urine, important in host location and particularly attracted to dark moving objects.  Glossina sp: The Life-cycle 3 groups i.e Fusca (forest flies), Morsitans (savannah flies) and Palpalis (riverine and forest flies). Fusca (forest flies): – 13 species – 10.5-15mm long – rarely feeds on people and not a vector of sleeping sickness. Morsitans (savannah flies): – 5 species – 7.5-11mm long – G. morsitans, G. pallidipes and G. swynnertoni are vectors of sleeping sickness; though G. morsitans is not a vector in West Africa. Palpalis (riverine and forest flies) – 9 species – About 6.5mm long and the largest is 11mm. – G. palpalis, G. fuscipes and G. tachinoides are vectors of sleeping sickness. Transmission of Trypanosomiasis  Transmission of Trypanosomiasis About 30,000 new cases a year, but WHO estimates actually about 400,000 new cases a year and 55,000 deaths. Occurs in 36 African countries – patchy distribution. 2 subspecies of trypanosomes causing human sleeping sickness i.e. T. brucei gambiense and T. brucei rhodesiense (zoonosis) – morphologically undistinguishable but different in clinical symptoms. Important vectors: 1. G. palpalis 2. G. fuscipes 3. G. tachinoides 4. G. morsitans 5. G. pallidipes Geographical distribution of African Trypanosomiasis Control of the tsetse flies Control is aimed at adult flies. Culling of reservoir hosts i.e. bovids, wild pigs, reptiles and birds. Destruction of surrounding vegetation. Insecticidal control: – Endosulfan, permethrin, deltamethrin, lamda-cyhalothrin and cypermethrin can be sprayed onto vegetation – dry season 1.5m; 3.5m in wet season. – Remain effective for about 2-3 months. – ULV aerial insecticidal spraying – need re-spraying 5-6x at 12-18-day intervals. – Spraying or dipping cattle with pyrethroid insecticide reduce number of human trypanosomiasis. Targets and traps Genetic control Pheromone traps End of lecture! Introduction to Medical Entomology MDU 1043 Family Tabanidae (Horse Flies) Session 2023/2024 15 May 2024 Dr Khatijah Yaman Outline of Lecture Family Tabanidae Medically important species Diseases caused in human Mode of transmission and distribution of disease vector Control methods  Family Tabanidae – Horse flies They are medium to large biting flies (6-30mm). Comprises of 4300 species and subspecies and 133 genera Important genera include Tabanus (some known as greenhead), Haematopota (clegs and stout) and Chrysops (deer flies). They have been incriminated in the spread of anthrax and tularaemia and might be involved in the transmission of Lyme disease. The main medical importance genera is Chrysops i.e. C. silaceus and C. dimidiatus – vectors of filarial worm, Loa loa in West and Central Africa. They have a worldwide distribution: Chrysops and Tabanus are found in temperate and tropical areas. Family Tabanidae: Chrysops sp  Family Tabanidae: Chrysops sp Known as deer-flies. They are robust and heavily built. Medium size about 6-12mm. Most species have iridescent eyes, commonly with spots of red, green or purple. The wings are partially held over the abdomen in an open scissor-like fashion; have one or more brownish transverse bands. The abdomen is blackish with orange or yellow patches or bands. There is no antennal arista. Antennae consist of 3 segments; the last segment is subdivided into 3 or 4 small divisions by annulations.  Antennae consist of 3 segments; the last segment is subdivided into 3 or 4 small divisions by annulations. Antennae is the best feature to differentiate Chrysops from other Tabanids (i.e. Tabanus and Haematopota) i.e. differences in size and shape of the antennae. The mouthparts of female Tabanidae are stout and adapted for biting which hang down from the head. The stout thorax bears a pair of wings which have 2 submarginal and 5 posterior cells and completely closed discal cell in approximately the centre of the wings. Wings may be completely clear and devoid of colour, have a brown colouration areas be distinctly banded or appear mottled or speckled due to greyish patches.  Family Tabanidae: Chrysops sp (…cont.) At rest, wings placed either like a pair of open scissors over the abdomen or at a roof-like angle completely obscuring the abdomen. The presence or absence of coloured areas on the wings and the way in which they are held over the body provides useful additional characters for distinguishing among genera. The abdomen is more or less uniformly dark brown, blackish, light brown, reddish brown, yellowish or greenish or alternatively marked with contrasting coloured stripes or patches. Adult males and females feed on sugary secretions, and females also bite (for blood meals) mammals including humans, domesticated animals (esp. horses, cattle, deer, etc.) and also carnivores and monkeys. Differences in antennae: Chrysops vs Tabanus Chrysops sp Tabanus sp  Difference in head: Female vs Male female with dichoptic eyes male with holoptic eyes Difference in head: Female vs Male Family Tabanidae: Life cycle  Family Tabanidae: Life cycle Eggs ❖ 100 – 800 eggs in a single large mass (lozenge-shaped pattern) firmly glued in an upright position on the underside of objects e.g. leaves, grassy vegetation, twigs, small branches, stones and rocks. ❖ Creamy white, greyish or blackish in colour, 1-3mm long and has shape like a cigar. ❖ Hatch after 4-14 days (depending on the temperature and species) when wriggled out from the eggs into young larvae drop down on to the underlying mud or water. Larva ❖ Cylindrical in shape and has rather pointed ends. ❖ Creamy white, brown or greenish in colour but often have darkish pigmentation near the borders of the segments. ❖ Chrysops larvae are mainly scavengers, feeding on detritus and organic matter. ❖ Larval developmental is of 1-2 years in both temperate and tropical countries, and can be up to 3 years in cold-temperate countries. ❖ 10-16 instar larvae Family Tabanidae: Life cycle Pupae ❖ Partially buried in the mud or soil in an upright position. ❖ Distinctly curves and usually brown in colour. ❖ Large ear shaped spiracles on a cephalothorax. ❖ Caudal aster on the last abdominal segment. ❖ Pupal period about 5-20 days. Adult ❖ Feed daytime; esp. in bright sunshine. ❖ Powerful fliers; disperse up to several km. ❖ Chrysops commonly found in low-lying marshy scrub areas or swampy woods, but some are found in savannah and grassland areas. ❖ Only C. silaceus enter houses to feed and also attracted to smoke from wood burning or forest fire. Medically important species in Tabanidae family Chrysops sp is the only genus in Tabanidae family that transmitted Loa loa nematode to human when blood feeding. The diurnally periodic microfilariae are readily picked up by C. silaceus and C. dimidiatus which bite during the day. C. distinctipennis and C. longicornis are the vector in Bahr-el-Ghazal, Sudan. C. centurionis and C. langi, crepuscular and nocturnal are the vector of Loa loa in monkey in which the microfilariae appear in the peripheral blood at night. Other medically importance: 1. Allergic symptoms 2. Pest 3. Mechanical vectors for spread of anthrax (Bacillus anthracis), tularaemia (Francisella tularensis) e.g. C. discalis in North America, Lyme disease, trypanosomiasis (Trypanosoma vivax) Tabanids transmit viruses, bacteria, protozoa, and filarial worms to livestock - veterinary importance. The transmission of loasis by Chrysops sp. The signs and symptoms Geographical Distribution of Loasis in Africa  Control of the horse flies Control of larvae is difficult due to unknown breeding sites. Practical measures to control tabanid flies: 1. Efficient drainage of larval habitats might reduce adult population 2. Local control by employing attractant traps i.e. coloured screens coated with adhesive to catch adult flies. 3. Personal protection (insect repellent) to avoid from biting female flies. End of lecture!