Effect on the host

EFFECT ON THE HOST - SHEEP NASAL FLIES

Due to adult fly

  • The very presence of the flies causes panic in sheep
  • The flies may cause gadding in animals which run madly about resulting in injury and even death of young animals
  • The animal stops feeding, becomes restless, shake their heads or even press their noses to the ground or between other sheep in an attempt to avoid the fly from larvipositing.  Since the feed intake is affected the condition of the animals deteriorate

Due to larval stages

  • The first stage larvae moves around in the nasal passage causing considerable irritation with its oral hooks and spines. This result in the secretion of a viscid mucous exudates on which the larvae feed.  At times the damage may result in blood tinged mucous being secreted
  • The infected sheep shakes its head, has a nasal discharge and sneezes frequently
  • The nasal region of the affected sheep is dirty in appearance and hence the condition is sometimes called ‘snotty nose’
  • Sometimes from the frontal and maxillary sinus the second stage larvae may accidentally move towards the brain, causing injury to the brain and even erosion of the skull all of which leads to neurological symptoms in sheep which resemble the condition caused by Coenurus cerebralis.  Hence the condition is termed as ‘False gid’ or ‘sturdy’
  • At times the larvae are deposited by the adult fly on man- frequently affected are the shepherds who are in close contact with the animals
  • The larvae have been reported to have been deposited on the eyes, nostrils, gums, lips etc., of man
Last modified: Saturday, 7 August 2010, 5:52 AM