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ENTO3645 Midterm 3 (myiasis)

Terms in this set (21)

Myiasis
Infestation of live human and vertebrate animals with dipterous larvae which at least for a certain period of time feed in the host's living/dead tissue, liquid body-substances or infested food
Accidental Myiasis "Pseudomyiasis"
Dipterous larvae round in the digestive tract of man or animals which have been accidentally infested with food or water

Normally no pathological manifestations

Larvae especially come from the families:
1) Psychoidae
2) Syrphidae
3) Tephritidae
4) Calliphoridae
Facultative Myiasis
Diptera whose larvae normally develop in decomposing organic matter, but will occasionally invade necrotic tissue of living animals

"Wool maggots" only a minor problem in Western Hemisphere
Obligatory Myiasis
Species of Diptera having larvae which normally develop in or on the body of living vertebrates
Gastrerophilinae
Digestive tract (Obligatory Myiasis)
Oestrinae
Nasopharyngeal cavities and other internal respiratory systems (obligatory Myiasis)
Hypodermatinae and Cuterebrinae
Dermic or subdermic (obligatory Myiasis)
Calliphoridae (Cochliomyia hominivorax)
Wound (obligatory Myiasis)
Common characteristics of oestrid flies
1) robust larvae known as "bots" or "grubs" which are all obligate parasites of mammals
2) 1st instars enter host, molt twice, and spend entire larval life inside host as parasites
3) 3rd instars leave host to pupate in soil
4) adults are bee-like with reduced mouth parts and do not feed
Subfamily Gasterophilinae- Damage
1) violent reaction of horses to presence of ovipositing female - injure themselves
2) first instars irritate oral tissue (pus pockets)
3) attachment to stomach wall in large numbers probably interferes with digestion
4) larval migrans from 1st instars
Hypoderma
bot flies do not feed as adults so must acquire all their nutrition as larvae inside the host
Hypoderma Damage
1) gadding
2) meat trim
3) host reaction
4) abscesses (rare)
5) hide damage
Systemic control of grubs and bots
macrocyclic lactones, esp. avermectins
Cuterebra emasculator "wolf"
squirrel bots, sometimes also found in dogs and cats
Dermatobia hominis eggs
eggs attached to body of zoophilous flies or mosquitoes (phoretic vectors)

vectors tend to be those with zoophilous habits, diurmal fliers and moderate in size and activity

families include: culicidae, simuliidae, tabanidae, fanniidae, anthomyidae, muscidae, sarcophagidae, and calliphoridae
Dermatobia homins in cattle
host preferences due to vector, not D. hominis

pattern of furuncles is often a clue to vector
Dermatobia hominis general
wide range of potential hosts, especially cattle, but also in wild and domestic mammalian hosts, including humans
New World screwworm fly larvae (wounds)
no longer breed in carcasses, but instead dependent on living tissues and therefore live animals
Screwworm eradication using the sterile insect technique
male flies from colony are sterilized using radiation

millions of flies are released by air over screwworm-infested areas

wild female screwworms mate with sterile males, becoming refractory to further mating

effort supplemented with insecticide applications
Philornis dawnsii
external parasitic maggot that burrow into nestlings and drinks their blood

inadvertently introduced to the Galapagos Islands, where it is threatening the endangered Darwin's finches
Maggot debridement therapy
the use of medical grade larvae of the greenbottle fly to dissolve dead and infected tissue from wounds

stimulate wound-healing

secrete allantoin

antibacterial secretions

FD regulated
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