Sheep nasal bot - Oestrus ovis

Question 1

What are some morphologic features of Oestrus ovis (sheep nasal bot)?

Answer 1

• ~1cm long
• grey in color with small black spots on dorsal abdomen
• covered in short brown hairs
• adults have non-functioning mouthparts
  
  • short lived (~2weeks)
  • don’t feed

Question 2

What are some general characteristics of the sheep nasal bot (Oestrus ovis) life cycle?

Answer 2

• L1’s migrate to frontal sinus
• L1-3 in nasal sinuses
• L3’s migrate back to nostrils then sneezed onto ground
• L3’s burrow into soil and pupate
• adults emerge and quickly mate
• females viviparus and deposit packages of larvae (~25) into nostrils
  
  • can lay ~500 larvae in their lifetime
• 2-3 generations per year

Question 3

What is the pathogenic significance of sheep nasal bots (Oestrus ovis)?

Answer 3

• hooks on margins of body segments, oral hooks
• most infections light
• nasal discharge
• sneezing, rubbing nose
• septic sinusitis if larvae die in sinus
  
  • can spread to brain (false gid)
• mainly just annoying, interrupted feeding
  
  • sheep face each other in circle when flies most active

Question 4

Are sheep nasal bots (Oestrus ovis) biting flies?

Answer 4

No, adults have non-functioning mouthparts.