Enzootic Abortion in Sheep

Enzootic abortion (sometimes called Chlamydiosis) was relatively unknown in the country until 1972 whereby there was a massive outbreak of abortions and stillbirths in ewes. In some flocks . . .

Enzootic abortion (sometimes called Chlamydiosis) was relatively unknown in the country until 1972 whereby there was a massive outbreak of abortions and stillbirths in ewes. In some flocks abortions were as high as 60%.


WHAT CAUSES ENZOOTIC ABORTION?

This disease is caused by an organism called Chlamydia psittaci and is one of the biggest causes of abortions and stillbirths in sheep and goats. This organism is found throughout the world, including South Africa. There are other syndromes associated with this disease, for example, respiratory tract and digestive tract infections. The organism may infect a wide range of hosts including cattle, birds and humans.

HOW IS THE DISEASE TRANSMITTED?

The disease is normally introduced into a flock by the purchase of an infected ewe. The vaginal discharge and after-births of infected sheep are highly infective and will contaminate the pastures. The organism can also be shed via faeces. Ewe to ewe infection usually occurs during lambing time.

CLINICAL SIGNS

There are no apparent clinical signs in ewes in infected ewes. Abortions normally occur during the last month of pregnancy. The farmer's biggest concern will be a low lambing and weaning percentage. Apart from abortions, affected ewes give birth to weak and unthrifty lambs, most of which will die within a few days.

CONTROL OF ENZOOTIC ABORTION

The lower lambing and weaning percentages associated with this disease obviously impacts negatively on the farmer's profitability. Intervet markets Ovilis Enzovax - a quality vaccine for the control of Chlamydiosis in sheep and goats. The use of Ovilis Enzovax vaccine has shown improvements in lambing percentages and reduction in abortion rates in flocks having problems with Chlamydiosis. One of the major benefits of this vaccine is that the immunity lasts for 2 years. This means less handling of animals and also a saving on costs as compared to vaccines that have to be administered every year.

WHAT IS OVILIS ENZOVAX?

Ovilis Enzovax is a live, attenuated vaccine containing >- 105.0 IFU of Chlamydia psittaci per dose. Ovilis Enzovax is indicated for the active immunisation of susceptible breeding female sheep as an aid in the prevention of abortion and stillbirths by Chlamydia psittaci infection.

WHEN TO VACCINATE?

Ewes should be vaccinated at least 4 weeks before mating. Ewe lambs intended for breeding can be vaccinated from 5 months of age. Do not vaccinate pregnant animals or animals which are being treated with antibiotics, particularly tetracyclines.