Strangles in a Pregnant Mare: British Researchers Investigate Disease Outbreak and Help a Foal to a Healthy New Life

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Thanks to the diligence of vets at England's Animal Health Trust, and funding from leading charity The Horse Trust, a newborn foal has escaped the potentially fatal disease of equine strangles. This story is shared from our friends at the AHT:

A pony mare named Bobbles was one of a number of horses and ponies affected by an outbreak of strangles at a stable in the British county of Norfolk. The mare's owner became concerned when she noticed a swelling the size of a tennis ball in the pony's neck.

"I called my (local) vet immediately" she said, "and she contacted The Animal Health Trust, which is renowned for its expertise in infectious diseases."

The Trust's diagnostic laboratory soon confirmed the diagnosis of Strangles, one of the most common and feared infectious diseases of horses worldwide. It causes a range of clinical signs, including fever, profuse nasal discharge and abscesses of the lymph nodes in the head and neck. These often erupt through the skin to release highly infectious pus. As a result, the disease spreads easily and quickly within groups of horses.

Although the condition causes a high degree of suffering, most horses do eventually recover. However, some horses remain long-term carriers of the disease even after recovery, and they can then infect other horses and start new outbreaks.

When the pony mare's sample was deemed positive, Trust vet Jeremy Kemp-Symonds arranged to visit the farm and test all the horses and ponies there. As he had suspected might be the case, the disease had already spread widely.

As part of the project, Jeremy monitored all the horses carefully and, within two months, they all appeared to have made a recovery.

However, tests showed that Bobbles, the pony mare, was a carrier of strangles and therefore still capable of infecting other animals. It was therefore necessary to isolate her immediately. Unfortunately, there was a further complication: Bobbles was pregnant and there was a very high chance that her foal would be infected soon after birth.

"This was a major concern," says Jeremy Kemp-Symonds "because the fatality rate in very young animals can be around ten per cent. We therefore decided to treat the mare with penicillin. Thankfully we managed to clear the infection completely before Nelson was born".

In other Strangles-related news from England, the pharmaceutical firm Intervet has recalled all batches of its strangles vaccine, EquilisStrepE. The firm is currently unable to advise when the product will become available again, although it is unlikely to be this year (2007).

Quality monitoring indicated that the vaccine's antigen level had decreased slightly over time and dropped below the approved release requirements.

As there is no alternative vaccine available in Britain for the time being, Intervet advises horse owners to follow adequate stable management and hygiene procedures to minimise the risk of disease and to be vigilant for symptoms.