Melophagus Infestation

Synonyms

'Sheep Ked'

Introduction

Melophagus ovis is a wingless fly, also known as the sheep ked or 'louse fly', which parasitises the skin of sheep. It is similar to a louse as its' whole life cycle occurs on the host.

Melophagus is the intermediate host for the non-pathogenic Trypanosoma melophagium in sheep.

The fly often lives on sheep without any clinical signs, but in severe infestations, clinical signs will ensue. The disease manifests most commonly in autumn and winter. The parasite is found in the superficial layers of the fleece and this aids transmission to other sheep by direct contact. Long wooled breeds are most susceptible to infection.

Clinical signs

The sheep may appear generally off colour. There will be noticeable wool damage and this will be due to self- trauma through itching. The fleece will also appear stained by the faeces of the sheep ked. On physical examination, anaemia may also be noted if the parasite burden is big enough.

Diagnosis

By clinical signs and detection of the parasite on the sheep. Microscopic examination will determine the presence on Melophagus.

Treatment and Control

Treatment upon clinical signs and diagnosis, with a suitable ectoparasiticide.

Control measures include sheep dipping and sprayingand shearing to decrease numbersof the ked.