Flies

Question 1

• Obligatory myiasis causing fly
• Larvae feed on live tissue
• Eggs laid at edge of wound–> larvae hatch and feed, become 3rd stage in 5-7 days–> drop to ground, pupate in soil–> adults in 1 or more weeks
• Fatal if untreated
• Females only mate once
• Self sustaining populations in US eradicated by releasing sterile males, and treating infected animals
• Reportable

Answer 1

Cochliomyia hominovorax

-American primary screw worm

Question 2

• Obligatory myiasis causing fly
• Throughout US
• Life cycle takes a year
• Eggs on hair shaft–> hatch–> larvae burrow and migrate through subcu tissues–> submucosal connective tissue of esophagus–> migrate to subcu of back, cut breathing whole, develop to 3rd stage–> exit through hole, pupate in soil–> adults
• Adults don’t feed, but annoy animals with egg laying behavior
• Larvae damage carcass and hide, bloat or choke if larvae treated when around esophagus–> treat no later than 8 weeks after fly season

Answer 2

Hypoderma lineatum

-Primary cattle grub

Question 3

• Obligatory myiasis causing fly
• Northern US
• Life cycle takes a year
• Eggs on hair shaft–> hatch–> larvae burrow and migrate through subcu tissues–> epidural fat–> migrate to subcu of back, cut breathing whole, develop to 3rd stage–> exit through hole, pupate in soil–> adults
• Adults don’t feed, but annoy animals with egg laying behavior
• Larvae damage carcass and hide, CNS damage if larvae treated when around spinal chord–> treat no later than 8 weeks after fly season

Answer 3

Hypoderma bovis

-Norther cattle grub

Question 4

• Obligatory myiasis causing fly
• Egg on hair late summer early fall–> hatch in response to horse’s warm breath–> migrate in oral mucosa and tongue to stomach, duodenum, rectum–> attach to wall–> pass out in feces in spring–> pupate
• Can cause ulceration of tongue, adults cause annoyance

Answer 4

Gastrophilus intestinalis, nasalis, hemorrhoidalis

-Horse stomach bot

Question 5

• Obligatory myiasis causing fly
• First stage larva deposited in nostril–> migrate into nasal sinuses, develop into large, brown, 3rd stage larvae–> crawl or are sneezed out–> pupate on ground 3-6 weeks, or over winter
• Pruritic rhinitis or sinusitis–> head shaking, snorting, may damage cribriform plate–> brain injury

Answer 5

Oestrus ovis

-Sheep nasal bot

Question 6

• Obligatory myiasis causing fly
• Rabbits and rodents = primary host–> can infect dogs and cats–> zoonotic
• Eggs laid near burrow entrances or rabbit runs–> larvae hatch in response to animal–> enter subcu through natural body openings–> cut breathing holes–> large black 3rd stage
• Usually on neck or head = benign, abberant locations can be harmful

Answer 6

Cuterebra spp.

Question 7

• Periodic parasitic fly
• Horses are preferred host, but will feed on most domestic animals and humans
• Painful bites, annoyance–> decreased production

Answer 7

Stomoxys calcitrans

-Stable fly

Question 8

• Periodic parasitic fly
• Cattle are preferred host–> irritation–> most economically important fly in cattle responsible for reducing production

Answer 8

Haematobia irritans

-Horn fly

Question 9

• Periodic parasitic fly
• Feed on all types of livestock, horses, bison
• Vector for pinkeye

Answer 9

Musca autumnalis

-Face fly

Question 10

• Periodic parasitic fly
• Nuisance
• Feed on available, blood, sweat, saliva and tears
• Facultative myiasis
• Vector for enteric pathogens

Answer 10

Musca domestica

-House fly