Ectoparasites VI: Diptera Flashcards
What are general dipteran characteristics?
True flies (two-winged) Complex metamorphosis
What do larvae of some species of dipterans cause? What are adults of others?
Myiasis
Blood-suckers
Describe the mouthparts of dipterans
They vary:
Lapping, piercing, combination, nonfunctional
What are the 2 main groups of diptera?
Brachycera
Nematocera
What are examples of Brachycera?
Myiasis flies (bot, blow, flesh, and muscid flies) Stable flies Horn flies Keds (louse flies) Horse and deer flies
What are examples of Nematocera?
Mosquitoes
Biting midges
Black flies
Sand flies
What is the parasitic stage for Brachycera?
Larval stage
Where do most Brachycera breed?
In decaying material
What are the mouthparts seen with Brachycera?
Lapping, piercing, nonfunctional
What is myiasis?
Parasitism by fly larvae
What are obligate parasites?
Those that require living tissues
What are facultative parasites?
Those that go for necrotic tissue
What are accidental parasites?
When an animal ingests something with maggots and they pass through, but they aren’t meant to be there
Describe Oestridae (Bot flies)
Highly host and site specific
Adults non-parasitic
Aberrant hosts
What is the type of myiasis associated with Oestridae subfamily Gasterophilinae?
Digestive
What is the type of myiasis associated with Oestridae subfamily Oestrinae, Cuterebrinae?
Internal
What is the type of myiasis associated with Oestridae subfamily Cuterebrinae, Hypodermatinae?
Cutaneous
What are the Gasterophilinae species from most common to least common (horse bots)?
Gasterophilus intestinalis
Gasterophilus nasalis
Gasterophilus hemorrhoidali
What is hatching of Gasterophilus eggs induced by?
Environmental cues
Where are eggs laid with Gasterophils intestinalis?
Legs and shoulders
Where does the L3 stage occur with Gasterophilus intestinalis?
Nonglandular portion of stomach
Does Gasterophilus cause pathology?
Usually it causes very little pathology
Some association with stomach rupture, splenic abscesses, peritonitis
How is Gasterophilus diagnosed?
Often postmortem, but sometimes we can find eggs
What are the infestation signs of Oestrus ovis (sheep bots)?
Usually subclinical
Sometimes sneezing, nasal discharge, blockage
Where is Oestrus ovis found?
In the nose of sheep
What are the hosts of Cuterebra?
Rodents and squirrels are most common
Rabbits, dogs, cats
Where do Cuterebra adults lay eggs?
In the host habitat
How do Cuterebra larvae get into host?
They get onto the host fur and enter via natural openings, then migrate to subcutaneous location
Where does Hypoderma (cattle bot) lay eggs?
On the host legs
Where does L1 of Hypoderma occur?
Esophagus and spinal cord
What happens with the other stages of Hypoderma?
They move to SubQ areas because part of their life cycle is exiting the host
When does injury occur with Hypoderma?
When trying to escape flies
Why is the timing of treatment of Hypoderma important?
You don’t want to treat L1 when they are in the esophagus or spinal cord because dead larvae release toxins which causes adverse reactions
When do you want to treat Hypoderma?
Immediately after fly activity stops- NOT in winter
Describe Calliphoridae blow flies
Adults have metallic color
Lay eggs/larvae in tissue
Most are facultative parasites, some obligate
What are screwworms (Calliphoridae- Blow flies)?
Primary: Cochliomyia hominivorax (reportable)
Secondary: Cochliomyia macellaria
Where are Sarcophagidae (flesh flies) eggs laid?
Carrion, feces, wounds
What can many Sarcophagidae cause?
Facultative myiasis
Where do you usually find Muscidae larvae?
In decaying organic matter
What is the pathogen transmission with Musca domestica (house fly)?
Mechanical (bacteria and viruses)
Biological (horse nematodes)
What does Musca autumnalis (face fly) feed on?
Ocular/nasal discharge
What is the pathogen transmission of Musca autumnalis?
Mechanical (bacteria)
Biological (nematode)
What is cutaneous myiasis associated with?
Larval infestation from blow flies, flesh flies, and rarely muscid flies
What are clinical signs of cutaneous myiasis?
Foul-smelling
Depressed or restless
Decreased weight gain
Describe treatment of Cutaneous myiasis in small animals
Treat individual
Clean wounds
Remove maggots
Avermectins
Describe treatment of Cutaneous myiasis in large animals
Individuals are often not treated
Dips/sprays
Suffocation approaches
What are muscid flies that are blood feeders as adults?
Stable flies (Stomoxys) Horn flies (Haematobia)
Describe stable flies
Quick feeder
Breed in manure with feed
Describe Horn flies
Slow feeder
Breed in manure only
What are the common hosts of Stomoxys calcitrans?
Dairy cattle, dogs, horses, humans
What is Stomoxys calcitrans the biological vector of?
Nematode (Habronema microstoma)
What are common hosts of Haematobia irritans?
Beef cattle, horses
What is Haematobia irritans the biological vector of?
Nematode (Stephanofilaria stilesi)
What are the general control methods of Muscidae?
Sanitation
Regular spraying of premises
Fly baits, resin, strips, ear tags, UV traps
Biological control
Describe Hippoboscidae (Keds)
Many are not host specific
Dorsoventrally flattened
Piercing/sucking mouthparts
Some stay on host whole life cycle, others don’t
Larvae stay in female’s abdomen until ready to pupate
Describe Melophagus ovinus (Hippoboscidae)
Transfer via direct contact
Entire life cycle on host
Trypanosoma melophagium
Describe Lipoptena cervi (Hippoboscidae)
Wings break off once
Describe Hippobosca equina
Wings throughout life
Describe Tabanidae
Horseflies and deerflies
Stout-bodied. vary in size
Only adult females require bloodmeal
What are the eggs of Tabanidae like?
Glued to vegetation overhanging water
What is L3 of Tabanidae like?
Carnivorous
What are adult Tabanidae like?
Strong fliers
Difficult to control
Describe Tabanus spp. (horse flies)
Vary in size, but can be big
Large eyes
Livestock fighting off flies may not graze well
Describe Chysops spp. (deer flies)
Smaller than Tabanus spp, but larger than house fly
Banded wings
Larvae feed on organic matter in soil
What disease does Tabanidae transmit via mechanical transmission?
Anthrax (Bacillus anthracis)
Anaplamosis (Anaplasma marginale)
Tularemia (Francisella tularensis)
EIA (Equine infectious anemia virus)
