Exam III - Oestrus ovis

Question 1

who is the host for Oestrus ovis & what is its common name?

Answer 1

sheep & goats +/- humans

nasal bot fly

Question 2

Oestrus ovis female fly will deliver 25 larva into the nares of sheep with a “squirt” of fluid during flight. larva will remain in the nostral of sheep for 2wks(summer) to 9months(winter). during this time the sheep will secrete a lot of mucus from its nose. why?

what happens to the larva after this time period?

Answer 2

the larva cause irritation of the nasl mucosa from their venteral spines and oral hooks.

after maturation 2wks-9 months the larva drop out of the sheep and pupate on the ground.

Question 3

what are the behavioral CS’s seen by sheep to avoid attacks from Oestrus ovis?

Answer 3

pressing there nose to the ground, hiding there head between other sheep, panicing and stomping of feet.

Question 4

What is the result of sheep that spend a lot of there time avoiding attacks from Oestrus ovis and not grazing?

Answer 4

wt loss = decrease production yield.

Question 5

If a human becomes the target of Oestrus ovis and becomes infested with the larva what is the result?

Answer 5

Oestrus ovis larva never fully develop in humans but are commonly laid on the eye & lips.

Question 6

what is one of the Tx strategies for Oestrus ovis in sheep?

Answer 6

tx with MCL’s at the beginning of summer to kill newly aquired larva and again in midwinter to kill overwinter larva.

Question 7

the adult fly is gray and can be up to 1cm long. How long can the mature larva get?

Answer 7

up to 3cm

yellow with dark transverse bands

1 inch = 2.4cm