Myiasis

Myiasis

Infestation of live human & vertebrate animals with dipterous larvae, which, at least for a certain period, feed on the host’s dead or living tissue, liquid body-substances or ingested food

* Muscidae
* Calliphoridae
* Sarcophagidae
* Gasterophilidae
* Oestridae

Myiasis-causing flies (Families)

*M. domestica, Fannia*

species under Muscidae

*Chrysomya, Lucilia, Calliphora, Cordylobia anthropophaga, Phormia, Auchmeromyia luteola*

species under Calliphoridae

*Sarcophaga, Wohlfahrtia*

species under Sarcophagidae

*Gasterophilus intestinalis*

species under Gasterophilidae

*Oestrus ovis, Hypoderma*

species under Oestridae

*Lucilia*

cutaneous myiasis

*Oestrus ovis*

nasal myiasis

*Hypoderma*

somatic myiasis

*Gasterophilus*

gastric myiasis

*Gasterophilus*

intestinal myiasis

obligate/specific

etiological classification of those larvae which must develop exclusively in or on living vertebrates e.g. *Cordylobia*

*Cordylobia*

example of obligate/specific species

facultative

etiological classification of those which are normally free-living, but occasionally may gain access to body e.g. via wound. e.g. *Chrysomya, Sarcophaga*

*Chrysomya, Sarcophaga*

examples of facultative species

accidental

etiological classification where ingestion of food contaminated with fly eggs e.g. Muscidae, Calliphoridae

Muscidae, Calliphoridae

examples of accidental species

wound myiasis

caused by *Chrysomya*

dermal & urogenital myiasis

caused by *Cordylobia*

intestinal & urogenital myiasis

caused by *Fannia*

nasopharyngeal/oral myiasis

caused by *Oestrus, Chrysomya bezziana*

blood-sucking myiasis

caused by *Auchmeromyia*

pruritis, pain, movement, tenderness

local symptoms of myiasis

* recent travel to an endemic area
* one or more non-healing lesions on exposed areas of skin
* a small, white, thread-like structure protruding from the lesion
* local symptoms of pruritis, pain, movement, or tenderness

key diagnostic features of myiasis

* surgical removal
* occlusion/suffocation approaches - “bacon therapy”

management & therapy of myiasis

injection of lidocaine, use of wooden spatulas

alternative treatment for myiasis

washing of wound

treatment of non-furuncular myiasis - wound myiasis

maggot debridment therapy

artificial myiasis

maggot debridment therapy

Maggots are intentionally applied onto wound. The maggots feed on necrotic tissues only and secrete biological active substance to promote healing.

* enzymatic liquefaction of necrotic tissue
* use of necrotic tissue for food by larvae
* mechanical washing out of bacteria by exudates
* destruction of bacteria by maggots excretions which contain anti-bacterial substance/s

different mechanisms of wound healing by maggots were suggested: