Melophagus ovinus

Melophagus spp
Kingdom	Animalia
Phylum	Arthropoda
Class	Insecta
Order	Diptera
Family	Hippoboscidae
Genus	Melophagus
Species	M. ovinus

Also known as: Sheep Ked - Louse Fly

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.

Identification

The adults are hairy, brown and around 6mm in length, and of the family Hippoboscidae. They have an segmented abdomen, and are wingless. M. ovinus has blood sucking mouthparts, and claws on the ends of the legs, designed to hold on to the host. They are dorso-ventrally flattened.

Life Cycle

They are permanent ectoparasites, feeding on the host. The female fly produce a single larvae at a time, and the larvae are held back until they are ready to pupate. The larvae undergo three larval stages before becoming fully developed. Pupation of the larvae occurs, and they are clearly seen on the fleeces of the sheep. These then later emerge as adults.

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 spraying and shearing to decrease numbervsof the ked.

Literature Search

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Melophagus publications