This document discusses myiasis, which is the infestation of human and animal tissues by fly larvae. It is classified as either obligatory, where the larvae develop inside the body, or facultative, where they develop in decaying flesh or wounds. Clinically, myiasis can affect the skin, nasal passages, eyes, ears, intestines or urogenital areas. Common causes include various blowfly, fleshfly, and botfly species. Symptoms depend on the type, but can include painful boils, creeping skin eruptions, or larvae visible in wounds or body openings. Treatment involves physically removing the larvae through extraction, irrigation, or medication in some cases.

1. MYIASIS
Syn : Blow/Bot/Fly-Strike

2. Introduction
• Gk : “Muia” – Fly ; Scot: ‘Boateig’ – Maggot ; Blow
– to deposit ; Screw – spinous horny projections
• infestation of body tissues of humans and
animals by the larvae (maggots) of Diptera –
Frederich William Hope (1840)
• 02 groups (based on Myasis-causation) :
Obligatory (Larval Stage in Mammalian body)
Facultative (Decaying flesh, Wound)

3. Clinical classification (ICD-10)
• DERMAL / SUB-DERMAL
• CUTANEOUS
– Creeping
– Furuncular
– Traumatic
•
•
•
•
•
NASOPHARYNGEAL
OPHTHALMOMYIASIS
AURICULAR
INTESTINAL
UROGENITAL

4. ETIOLOGY
Muscidae
(Wound Myiasis / Accidental)
-Musca domestica
(Housefly)
-Fannia canicularis
(lesser / latrine housefly)
Calliphoridae (blowflies – Metallic / Non-metallic)
•
•
•
•
•
•
•
Cochliomyia
(NW Screwworm)
Chrysomyia
(OW Screwworm)
Cordylobia
(Tumbu fly / Sahara fly)
Auchmeromyia
(Senegal Sucker/Congo floor m.)
Calliphora
(Bluebottle)
Lucilia (Phaenicia) (Greenbottle) MDT (Serricata)
Phormia
(Black blowfish)

5. Sarcophagidae: (Flesh flies)
-Sarcophaga
-Wohlfahrtia
Oestridae
-Dermatobia (human botfly) FM
-Gasterophilus (horse botfly) GI
-Oestrus
(Sheep nostril fly) NP
-Hypoderma (Warble heel fly) ?HES
Cuterebra
(Rabbit-rodent botfly)

6. • aa

7. CLINICAL FEATURES
FACULTATIVE / TRAUMATIC WOUND MYIASIS
Eggs / Larvae in suppurating tissues
Calliphora, Lucilia, Phormia, Sarcophaga
OBLIGATORY CUTANEOUS MYIAISIS
CREEPING ERUPTIONS
FURUNCULAR MYIASIS
Cordylobia, Cochliomyia, Dermatobia, Hypoderma,
Gastrophilus, Oestrus
assoc with HES / Constt symptoms ; Exposed areas

8. Traumatic Myiasis
• aa

9. Furuncular Myiasis
Insiduous, tender boils
central punctum
Serosanguinous discharge
posterior end of the larva,
Spiracles visible in punctum
Lymphangitis , regional LAN
Rapid resolution on removal
of larva

10. Creeping Eruptions
Resembles cutaneous larva migrans
tortuous, thread-like red line with terminal
vesicle marks the passage of the larva

11. • aa

12. • aa

14. TREATMENT
Wound myiasis
debridement and irrigation (Chloroform,
Turpentine guaze, Ether, Paraffin, Eusol)
treatment of secondary infections
Mechanical Forceps Extraction

15. Furuncular myiasis
traditional methods: pork fat, mineral oil,
petrolatum, butter, beeswax, cigarette ash,
chewing gum
surgical (I & D  Extraction)
Creeping Eruptions
Extraction beyond the vesicle
Ethyl Chloride freeze
Ivermectin 12mg PO stat ; Albendazole 400mg

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