Campylobacter in Sheep

One of the most common causes of contagious abortion in sheep.

Symptoms of the Disease/Condition

Campylobacter (Campylobacter fetus fetus) is one of the most common causes of contagious abortion in sheep. However, 30% of Campylobacter isolates from sheep abortions were diagnosed as species other than C. fetus fetus, the majority of these other species is Campylobacter jejuni.

This is a potential zoonosis!

C. fetus fetus and C. jejuni are both carried by ewes which show no outward signs of infection. The infection can be transmitted to susceptible animals by ingestion of contaminated feed and water but the most common means is direct contact with infected foetuses and placenta. Once an outbreak has started spread of infection speeds up as more ewes become exposed to the aborted foetuses and placenta.

Introduced carrier sheep (previously infected sheep carrying the bacteria in their gut) may bring an infection to a flock and an abortion storm may follow in younger sheep or older sheep that have no immunity.

Most Campylobacter abortion outbreaks appear in the last third of pregnancy about 7-21 days after infection.

Diagnosis is based on clinical history, culture of the organism from foetal stomach contents, placenta and vaginal discharges. 25% of infected foetuses show liver lesions which are characteristic of C fetus fetus species.

Cost/Impact on Herd/Farm Revenue

Abortion outbreaks and their impact on lambing performance are very obvious. However, Campylobacter has the potential to cause significant sub-clinical losses associated with early embryonic death (shows as increased dry rate at scanning) and decreased lamb survival. Ewes infected in the later stages of pregnancy give birth to lambs at normal term. The lambs look normal but are weak and struggle to get up and get a good feed of colostrum.

These sub-clinical effects may be occurring unnoticed so the farmer perceives the disease is not there.

However, the potential loss, and hence return on investment, increases with increasing lambing percentage. For example:

If lambs are worth $100, the lost opportunity with a 1% infection rate is.

  Lambing %           Cost/ewe mated 

        100%                       $1.00             

        120%                       $1.20 

        130%                       $1.30 

        140%                       $1.40

C. jejuni infection can cause ewe death as well as abortion.

If lambs are worth $100 & ewes $150, the lost opportunity with a 3% ewe death rate is:

Lambing %           Cost/ewe mated 

       100%                       $10.50             

       130%                       $11.40

Vaccination is the best option - there are a couple vaccines available.

The annual investment spread over 4 lambings is approx. $67 per 100 ewes so the programme only needs to save 1.3 lambs/100 ewes mated to provide a return.

The vaccination programme must be determined by the level of risk.

You may also be interested in Toxoplasmosis as a cause of abortion.