PPT ON FLIES AND MYIASIS MORPHOLOGY, AND MEDICAL IMPORTANCE

PPT ON FLIES AND MYIASIS MORPHOLOGY, AND MEDICAL IMPORTANCE

1. FLIES AND MYIASIS Presenter: Hoseenu Palilo Facilitator: Dr. Monica Shaban

2. PRSENTATION OUTLINE Introduction Classification Life cycle Medical importance Control measures

3. INTRODUCTION Myiasis - is the invasion of organs and tissues of humans or other vertebrate animals by fly larvae , which at least for sometime feed on the living or dead tissues or in the case of intestinal Myiasis, on the hosts ingested food. OR Myiasis - is caused when fly maggots (larvae of Diptera ) invade living tissue or when they are harboured in the intestine or bladder.

4. INTRODUCTION Types of Myiasis Accidental Myiasis Obligatory Myiasis Facultative Myiasis

5. INTRODUCTION Accidental Myiasis Involves eating food that is contaminated by eggs or larvae of flies that are not parasitic in mammals i.e. house flies Larvae survive for sometimes in the intestine, no larvae is adapted to cause intestinal Myiasis in human.

6. INTRODUCTION Accidental Myiasis Obligatory intestinal Myiasis occurs in other mammals The presence of larvae in human intestine cause considerable discomforts such as abdominal pain, bloody diarrhea, vomiting, passing living larvae in vomitus or stool

7. INTRODUCTION Obligatory Myiasis Is essential for the fly larvae (maggot) to live on a live host for at least a part of its life cycle. Eg larvae of C ordylobia anthropophaga, C ochliomyia hominivorax, D ermatobia hominis, and Chrysomya bezziana

8. INTRODUCTION Facultative Myiasis Are normally free-living, often attacking carcasses, but under certain conditions may infect living host. E.g. flies of spps Calliphora, Lucilia , Phormia , and Sarcophaga Usually breeds in meat or carrion, may sometimes cause facultative cutaneous Myiasis in people

9. INTRODUCTION Facultative Myiasis Sometimes facultative urogenital Myiasis occurs in human involving larvae of Musca or fannia spps Flies are attracted by the unhygienic urogenital discharges, lay eggs, and hatched larvae pass up the genital tract.

10. INTRODUCTION Myiasis can be termed differently depending on the affected body parts Cutaneous/ dermal/ subdermal Myiasis, creeping Myiasis Genital Myiasis Ophthalmic Myiasis/ ocular Myiasis Nasopharyngeal Myiasis Enteric/ GI Myiasis

11. INTRODUCTION Cutaneous Myiasis Ocular M yiasis

12. CLASSIFICATION Flies can be described in three families Calliophoridae Sarcophagidae Oestridae

13. FAMILY CALLIPHORIDAE Family Calliophoridae can be divided into two groups Metallic calliophorids Non metallic flies

14. CLASSIFICATION Metallic calliophorids Consist of B low flies comprising the bluebottles ( Calliphora species) and the green bottles (lucilia) N ew world screwworms ( Cochliomyia hominivorax ) Old world screwworms ( Chrysomya bezziana )

15. CLASSIFICATION Metallic calliophorids

16. METALLIC CALLIOPHORIDS Green bottles (Lucilia = phaenicia) Many spps of greenbottles occur in the genus Lucilia Has a worldwide distribution, most spps are in northern temperate regions Generic names Lucilia and Phaenicia are used interchangeably

17. Green bottles (Lucilia = phaenicia) External morphology Adults are mostly metallic or coppery green Are about 10 mm long Little less small and bristly than spps of bluebottles Prominent bristles occurs on the dorsal surface of the thorax

18. Green bottles (Lucilia = phaenicia) External morphology Squama of the wings lack hairs, while in bluebottles it is hairy dorsally Lucilia sericata commonest spp in America, Europe, Asia, Africa, and Australia Lucilia cuprina occurs in Africa, Asia, and Australia

19. Green bottles (Lucilia = phaenicia)

20. External morphological structures Thoraces of adult flies, showing the presence or absence of prominent dorsal bristles; and bases of the right wings, showing the presence or absence of fine hairs on the squama : A. Cochliomyia-note the three dark thoracic stripes and squama lacking hairs B. Chrysomya : note the absence of prominent thoracic stripes and the hairy squama C. Lucilia : note the prominent thoracic bristles and squama lacking hairs; (d) Calliphora: note the prominent thoracic bristles and the hairy squama.

21. Green bottles (Lucilia = phaenicia) Life cycle Greenbottles lies eggs on meat, fish, carrion, decomposing carcasses, foul smelling wounds, and decaying vegetable matters Eggs hatch within 8- 12hrs to a larvae which last for about 5-8 days Mature larvae burry in loose soil and pupate

22. Green bottles (Lucilia = phaenicia) Life cycle Pupae period last about 6-15 days

23. Green bottles (Lucilia = phaenicia)

24. Bluebottles ( Calliphora ) They have a global distribution, although are more common in northern temperate regions than in the tropical or southern temperate region The most important spps are Calliphora vicinia and C alliphora vomitoria

25. Bluebottles ( Calliphora ) External morphology Dull metallic bluish or bluish black Have well developed bristles on the thorax Squama of the wing is hairy on the dorsal surface The abdomen is more shiny than the thorax

26. Medical importance of metallic calliphorids Facultative Myiasis- involving the wounds, GIT, nasal passages Potential mechanical vectors of various pathogens- they feed on excreta, decaying materials, and all food makes Maggot therapy- use of sterile larvae to clean up ulcers i.e. pressure sores, infected surgical wounds. Frequently used spps are Lucilia sericata

27. Medical importance of metallic calliphorids Maggot therapy- sterile larva in biobag

28. Control of metallic calliphorids Physical and mechanical control Screening of windows with mesh Ultraviolet light traps to attract flies Fly papers, incorporating with sugar as an attractant Environmental sanitation- aim is to reduce larval habitat

29. Control of metallic calliphorids Reduce the number of bleeding sites, through waste management i.e. from slaughter house, domestic rubbish, an meat left to dry in the sun Garbage cans should have tight fitting lids Insecticidal control- organophosphates, pyrethroids, IGRs- directed against larva (larvicides) or adults

30. METALLIC CALLIPHORIDS New world screwworms (Cochliomyia) New world screwworms ( Cochliomyia hominivorax ) Formerly was present in USA, Mexico, central America, but currently have been eradicated through sterile male release Discovered in Libya in 1988, and was eradicated in 1991

31. METALLIC CALLIPHORIDS New world screwworms- Morphology They are 8-10 mm long Metallic green to bluish green Have distinct dark longitudinal stripes on dorsal surface of the thorax Dorsal bristles of the thorax are poorly developed Larvae have 7-9 finger like process on the anterior spiracles

32. METALLIC CALLIPHORIDS New world screwworms- Morphology Squama (membranous posterior border of the wing near the thorax) is devoid of hairs (as in lucilia)

33. METALLIC CALLIPHORIDS Old world screwworms (Chrysomya) The genus Chrysomya contain many spps Commonly found in the tropics About 10 spps are known to cause Myiasis in humans Chrysomya bezziana larvae are obligatory parasites of living tissues

34. METALLIC CALLIPHORIDS Old world screwworms (Chrysomya) C. bezziana occurs throughout tropical Africa , Indian subcontinent, southeast Asia Larvae of other Chrysomya spps aren’t obligatory parasites, often develops in carrion and decomposing matter

35. METALLIC CALLIPHORIDS Old world screwworms (Chrysomya)- morphology Adult Chrysomya bezziana are similar to Cochliomyia hominivorax but they lack distinctive thoracic stripes Dorsal surface of squama is covered with fine hairs Larvae are similar to those of C. hominivorax , but have 4-6 finger like process on the anterior spiracle

36. METALLIC CALLIPHORIDS Old world screwworms (Chrysomya)- morphology

37. METALLIC CALLIPHORIDS S crewworms life cycle

38. METALLIC CALLIPHORIDS Medical importance of screwworms Obligatory Myiasis leading to considerable disfigurement i.e. of the face and palate Potential vectors of various pathogens

39. NON METALLIC FLIES This group includes Congo floor maggot fly ( Auchemeryomyia senegalensis ) Tumbu fly ( Cordylobia anthropophaga ) Both spps are dull brownish color

40. NON METALLIC FLIES Cordylobia anthropophaga Are also known as Tumbu fly or mango fly Confined in almost the whole of African continent Little evidence that is found outside Africa Morphology Adult are large flies (9-12mm) long, dull yellowish to light brown with two dark grey poorly defined longitudinal thoracic stripes

41. NON METALLIC FLIES Cordylobia anthropophaga Morphology There are 4 visible abdominal segments which are more or less equal in length (second abdominal segment is longer in A. senegalensis )

42. NON METALLIC FLIES Cordylobia anthropophaga life cycle Female lays 100-300 eggs in several batches on dry soil or sand in shady places especially those contaminated with urine or excreta of human, dog, rodent, or monkeys. Oviposition can also be on underclothes or soiled babies nappies Eggs hatch after 3 days, larvae attach themselves directly to a suitable host or washed on the ground to dry

43. NON METALLIC FLIES Cordylobia anthropophaga life cycle Larvae get transferred to people when cloth are worn before ironed On the host the larvae buries itself except for its posterior spiracles (situated at the tip of the abdomen) There are 3 larval instars 1 st maggot shaped, 2 nd club shaped 3 rd fat, broadly oval shaped

44. NON METALLIC FLIES Cordylobia anthropophaga life cycle After 8-12 days a mature larvae wriggle out of boil like swellings and fall to the ground where they burry and turn into pupae Adult flies emerge 8-15 days later and feed on rotting fruits, carrion, and feces

45. NON METALLIC FLIES Cordylobia anthropophaga medical significance Boil like (furuncular) swellings Can be on any body part Sore, inflamed, hard, discharging serous exudate, do not usually contain pus

46. NON METALLIC FLIES Cordylobia anthropophaga prevention Washing should not be laid to the ground Iron clothes Dogs should be treated

47. NON METALLIC FLIES Auchmeryomyia senegalensis Morphologically are very similar to Tumbu fly except the 2 nd abdominal segment 2x long as others The Congo floor maggot was formerly common in certain parts of Africa, due to changes in life style it not much of the problem in these days

48. NON METALLIC FLIES Auchmeryomyia senegalensis Is commonly known as Congo floor maggot fly Not strictly speaking cause Myiasis, but the adults are confused with those of Cordylobia anthropophaga This spps occurs throughout most of the SSA Morphologically are very similar to Tumbu fly except the 2 nd abdominal segment 2x long as others

49. NON METALLIC FLIES C . Anthropophaga and A . Senegalensis

50. NON METALLIC FLIES Auchmeryomyia senegalensis life cycle Eggs are laid in batches on dry sandy floors of the m ud huts, hatch after 1-3 days and the larvae hide in cracks and crevices in the floor, more under the beds and sleeping mats/ they burrow in the soil At night larvae crawl out and takes blood meal from people sleeping on the floor, then return to their hiding places There are three larval instars, each requiring at least 2 blood meals

51. NON METALLIC FLIES Auchmeryomyia senegalensis life cycle Under optimum conditions the larvae period is between 3-4 weeks, but can be prolonged up to 3 months if the larvae fail to obtain regular feeds The 3 rd larval instar pupate in cracks or directly on the surface of the mud floors. After 9-20 days an adult emerge and feeds on rotting fruits and feces

52. FAMILY SARCOPHAGIDAE The spps of sarcophaga and wohlfahrtia are of medical importance They are also called fresh flies They are culprit of Myiasis and possibly act as mechanical vectors of pathogens Females are larviparous (they deposit first larval instar instead of lying eggs) Have a global distribution

53. FAMILY SARCOPHAGIDAE Sarcophaga spps They are large (10-25mm), hairy, and non metallic flies Usually are greyish and have three prominent black longitudinal stripes on the thorax S. cruentata- America, Europe, Africa, and Asia S. carnaria - common in palaearctic region

54. FAMILY SARCOPHAGIDAE Sarcophaga spps T he abdomen is sometimes marked with dark patches on a grey background giving it a chess-board appearance.

55. FAMILY SARCOPHAGIDAE Sarcophaga spps life cycle Adult female fly deposit 1 st instar in batches of 30-60 on decaying carcasses, human, animal excreta, rotting foods, and occasionally on wounds (facultative Myiasis) Larva development in hot weather last only 3-4 days, bury in the soil and pupate Puparial stage last about 7-12 days before an adult emerge

56. FAMILY SARCOPHAGIDAE Sarcophaga spps medical importance Facultative Myiasis- cause little damage they feed only on necrotic tissues Commonly incriminated with intestinal Myiasis- cause considerable discomfort and pain before the larvae is expelled in feces Mechanical vectors of various pathogens- adults frequently festering wounds, decaying matter, and feces

57. FAMILY SARCOPHAGIDAE Wohlfahrtia spps Are hairy flies, 8-15mm long, greyish in color, with three distinct lines on the thorax Dark markings on the abdomen present as roundish lateral spots and triangular shaped dark markings along the midline Old world- W. magnifica New world- W. vigil, W. opaca

58. FAMILY SARCOPHAGIDAE Wohlfahrtia spps

59. FAMILY SARCOPHAGIDAE Wohlfahrtia spps life cycle Adult female fly deposit 120-170 larvae in several batches, in scratches, wounds, sores, and ulcerations Larval development takes 5-9 days, after which mature larvae drops to the ground, burry themselves in loose soil and pupate Adult emerge from pupae after 8-12 days

60. FAMILY SARCOPHAGIDAE Wohlfahrtia spps medical importance Old world- W. magnifica causes obligatory Myiasis in humans and animals Frequently infested areas in human are ears, eyes, and nose- can lead to deafness, blindness, and even death Furuncular myiasis

61. FAMILY OESTRIDAE/ BOT FLIES The family Oestridae compose of 4 subfamilies One of the subfamily ( Cuterebrinae ) contains 58 spps in two genera that causes myiasis in rodents, monkeys, livestock The bot fly Dermatobia hominis causes obligatory myiasis in people and cattle in mexico , argentina , and chile D.hominis occurs in the lowland forest

62. FAMILY OESTRIDAE/ BOT FLIES Dermatobia hominis morphology Adult is 12-18mm long Have a similar dark blue metallic colored abdomen and dark bluish grey thorax, but the head is mainly yellowish Mouth parts are vestigial

63. FAMILY OESTRIDAE/ BOT FLIES Dermatobia hominis life cycle Female glue eggs to the bodies of other arthropods i.e. day flying mosquitos. Other deposit on house flies, stable flies, occasionally even ticks Embryos within attached eggs mature into 1 st instar larvae after 4-15 days Eggs do not hatch until the insect settle on human or other warm blooded animal for a blood meal/ sweat

64. FAMILY OESTRIDAE/ BOT FLIES Dermatobia hominis life cycle Larvae emerge from egg drop onto hosts skin Larvae penetrate through the bite puncture or penetrate soft unbroken skin and burrows into subcutaneous tissues Larval produce furuncular swelling which has an opening through which the larval breathes

65. FAMILY OESTRIDAE/ BOT FLIES Dermatobia hominis life cycle Mature larval wriggles out of the skin and drop to the ground, pupate under the soil surface An adult emerge from pupa after 4-18 weeks

66. FAMILY OESTRIDAE/ BOT FLIES Dermatobia hominis medical importance Invade various subcutaneous tissues in human causing boil like (furuncular) swelling Furuncular suppurate, may attract other flies

67. REFERENCES Klafehn EL. A Preliminary Investigation into the Effects of Lucilia sericata ( Meigen ) Blow Fly Larval Feeding on Sharp Force Trauma (SFT) Wound Patterns in Decomposing Bones of Sus scrofa domesticus . ResearchGate [Internet]. [cited 2024 Jul 9]. Figure 1. Life cycle of Cochliomyia hominivorax ( Coquerel , 1858).... Available from: https://www.researchgate.net/figure/Life-cycle-of-Cochliomyia-hominivorax-Coquerel-1858-Source-Own-authorship_fig1_342417573

68. REFERENCES ResearchGate [Internet]. [cited 2024 Jul 10]. Figure 2: Myiasis caused by Dermatobia hominis in a 33-year-old man.... Available from: https://www.researchgate.net/figure/Myiasis-caused-by-Dermatobia-hominis-in-a-33-year-old-man-Three-domiciles-were-noted-on_fig1_266380096 Williams K, Cronjé F, Avenant L, Villet M. Identifying flies used for maggot debridement therapy. South Afr Med J Suid-Afr Tydskr Vir Geneeskd . 2008 Apr 1;98:196–7.

69. REFERENCES Outbreak of Tumbu Fly Infestation [Internet]. NICD. 2018 [cited 2024 Jul 9]. Available from: https://www.nicd.ac.za/outbreak-of-tumbu-fly-infestation/