Final Exam: Bot flies and screwworms

Question 1

maggot infestation in animal/human tissue

Answer 1

myiasis
normally in tropics and subtropics
horse bots, cattle grubs, sheep/deer nose bot, primary and secondary screwworms

Question 2

3 types of myiasis

Answer 2

1) obligatory: essential for life cycle (horse bots, cattle grubs, primary screwworm flies)
2) facultative: usually in decaying organic matter-can develop in necrotic tissue (secondary screwworm flies, flesh flies)
3) accidental: non-specific, ingested (soldier flies, fruit flies)

Question 3

rodent bots egg laying strategies

Answer 3

lay 1200-1400 eggs around small animal burrows and runways
hatch in response to temp or CO2
enter hose around eyes, nose or wound (under skin for 3-6 days)

Question 4

cattle grubs/horse bots egg laying strategies

Answer 4

adult female finds host and lays eggs - 400 glues to hairs of hosts

Question 5

human/tropical bot fly egg laying strategies

Answer 5

glue eggs on “porters” (flies/mosquitoes/ticks that visit mammals) hatch in 5-10 min
protects eggs from host grooming “quiet porters

Question 6

3 types of horse bots

Answer 6

horse bot (most common)
throat bot fly
nose bot fly
invades horses, mules, and donkeys (humans can be invaded but die in a few days)

Question 7

Oviposition sites for common horse bot, nose and throat bot

Answer 7

Common: eggs on hair on inside of front legs; hatch with warmth and moisture from tongue; larvae left sac of stomach

nose: eggs on hair of muzzle and lips; hatch spontaneously; larvae on lower portions of stomach and duodenum
throat: eggs on hair of jaw and throat; hatch spontaneously; larvae on lower portions of stomach and duodenum

Question 8

horse bots life cycle

Answer 8

larvae in manure–> pupate in soil—> adult emerges and lays eggs –> develop in horse

larvae first burrow into tongue, gums, or mouth lining and stay for about 4 wks - molt and move to stomach for about 9 mo
absorb nutrition from horses stomach

Question 9

all 3 species of horse fly pupate

Answer 9

in the soil

Question 10

impact of horse bots

Answer 10

consume nutrients, interfere with food passage, cause stomach lesions, secondary infection sites, rundown appearance

Question 11

horse bot control

Answer 11

dewormers applied after kiling frost tokill larvae in stomach, sponging or slipping to remove eggs, egg scraper

Question 12

cattle grubs are also known as

Answer 12

warble

Question 13

oviposition sites for common and northern cattle grubs

Answer 13

common: single eggs on base of hair on legs or lower body regions; hatch spontaneously; larvae in mucosa of esophagus then to back
northern: single eggs on base of hair on legs or lower body regions; hatch spontaneously; larvae in tissue of spinal cord then to back

Question 14

how cattle grubs live in cattle

Answer 14

warble or cyst on back grows rapidly feeding on pus, necrotic cells and secretions from cyst. 2 mo there. squeezes thru breathing hole - pupates in soil

Question 15

when and how do mature cattle group larvae leave

Answer 15

leave thru breathing hole and pupate in the soil in the summer
NOT going through digestive tract!

Question 16

life cycle of cattle grubs

Answer 16

egg april-june
warbles dec-jan
pupation feb-late march

Question 17

cattle grub impact

Answer 17

injury fleeing from adults; carcass and hide value reduced; improperly timed treatments can kill migrating grubs in esophageal wall (causing drooling or bloat) or stiffness, muscular weakness, or paralysis of hind limbs

Question 18

gadding

Answer 18

jumping and bucking and trying to get away form buzzing of flies

Question 19

cattle grub control

Answer 19

dewormers applied depending location of cattle at time of heel fly activity
want to control before they get to a sensitive area (around esophagus and nerves) and before they are too big

Question 20

sheep nose bot

Answer 20

larvae deposited in nose; in nasal passages and sinuses of sheep and goats; profuse nasal discharge; can impari breathing - nasal infections

Question 21

larviposition

Answer 21

depositing a LIVE larvae rather than an egg

Question 22

sheep nose bot larvae exit

Answer 22

must be sneezed out - pupate in soil

Question 23

deer nose bot

Answer 23

have little spines that helps them with traction

Question 24

human bot fly

Answer 24

eggs laid on biting fly - mosquito, stable fly
mosquito on host triggers bot egg hatch
larvae burrow into skin
do not migrate

Question 25

primary screwworm fly (blow flies)

Answer 25

metallic green - maggots infest open wounds and destroy HEALTHY tissue; goes to liquid around wounds to feed

Question 26

primary screwworm fly host

Answer 26

any warm-blooded mammal

Question 27

screwworm fly mating

Answer 27

males mate several times, females only once

Question 28

where to primary screwworm flies pupate

Answer 28

soil

Question 29

primary screwworm fly oviposition

Answer 29

eggs laid on skin near open wounds

maggots feed in wounds then move to healthy tissue, toxic saliva promotes infection and foul smelling pus

Question 30

primary screwworm fly impact

Answer 30

infected animals may feed less, may die

Question 31

sterile male control

Answer 31

males sterilized by gamma radiation, wild females had little chance to mate with wild males –> females lay infertile eggs

Question 32

secondary screwworm flies (blow flies)

Answer 32

invade wounds or manure buildups but do not attack healthy tissue

Question 33

surgical maggots

Answer 33

intentional introduction of disinfected maggots into non-healing soft tissue wounds
reared under sterile conditions
removal of necrotic tissue, stimulates blood vessel growth

Question 34

example of a use of maggots with horses

Answer 34

laminitis

Question 35

secondary screwworm activity

Answer 35

maggots suppress immune system of host; reduce level of complement proteins involved in inflammatory response; faster wound healing due to increased O2 concentration in wound and enhanced cell growth