The Disease

In the United Kingdom, campylobacteriosis ranks third after enzootic abortion and toxoplasmosis as a cause of abortion and affects about 5 % of all abortions. Within affected flocks the abortion rate varies from 5 to 50 per cent (Gilmour, 1991).

Campylobacters are Gram-negative, non-sporing, curved or spiral rods. Campylobacteriosis in sheep is caused by either Campylobacter fetus ssp. fetus intestinalis or C. jejuni. Both are of significant zoonotic importance.

Active infection in pregnant ewes causes abortion in late pregnancy or full-term birth of dead or weakly lambs. The disease causes placentitis and the cotyledons separate easily from the caruncles. Abortions are more common beyond the twelfth week of pregnancy and usually occur between 7 and 25 days after infection (Gilmour, 1991).

Campylobacteriosis is transmitted orally through direct contact with infected faeces, vaginal discharge, aborted foetuses and foetal membranes. The disease can enter the flock through intestinal carriers from both bought-in stock and wildlife.

The disease is self-limiting, as immunity develops in the flock through contact with carriers. An outbreak is usually confined to one lambing season (The Henston Vade Mecum, 1998).