Page 646 - The Veterinary Care of the Horse

be investigated. Early diagnosis of EHV-1 infection is essential to prevent the spread of

infection. If abortion occurs:
VetBooks.ir • contact the vet immediately

•
isolate the mare in a stable
• put the foetus and membranes in a leak-proof container and send to an approved
laboratory for examination

• disinfect any areas likely to be contaminated by foetal fluids with a disinfectant

recommended by your vet
• burn any bedding

• if the mare aborted in the field it should be left empty for a period of four weeks.

• the person looking after the mare should not have any contact with pregnant mares
• sick newborn foals should be isolated with the mare and tested for EHV-1;

nasopharyngeal swabs and blood samples should be taken and sent to an approved

laboratory.

Until the results are available, no horses should be moved on or off the premises. All in-
contact mares should be managed as though infected.

If the tests are positive for EHV-1, the movement restrictions must be enforced for a
minimum of 28 days. Any other pregnant mares should remain on the premises to foal. There

is a Code of Practice to reduce the spread of the disease which is published by the Horserace
Betting Levy Board (HBLB) and is available from the HBLB (www.hblb.org.uk), the

Thoroughbred Breeders’ Association and the Welfare Department of the British Horse
Society. It is updated annually and offers guidelines on many aspects of disease control and
the movement of non-pregnant mares on and off the premises.

Prevention

VACCINATION

There is a vaccine available which gives some protection against EHV-1 and EHV-4.
Pregnant mares are vaccinated during the 5th, 7th and 9th months of pregnancy.

Foals may be vaccinated from 5 months of age. Following the primary course where the

first and second injections are given 4–6 weeks apart, boosters are recommended every 6
months. Immunity following vaccination and natural infection is relatively short-lived.
However, it may help to prevent infection by increasing herd immunity and reducing the