Equine Influenza: Why Take Nasal Swabs?

Influenza is one of the most contagious diseases of horses and therefore requires a timely and accurate diagnosis to help prevent a major outbreak. This diagnosis can be achieved only by testing clinical specimens from nasal swabs.

Rapid diagnosis facilitates rapid intervention, including quarantine and vaccination--historically the most successful means to prevent the spread of influenza. Vaccination in the face of an influenza outbreak can work if the horse has already been primed by previous vaccination and if at least a seven-day interval between vaccination and exposure to the disease has occurred.

Influenza is a moving target, often changing its viral coat to confuse the immune system. The vaccines have to be periodically updated to keep up with the changing viruses. The only way to keep the vaccines in step with the circulating viruses is to obtain samples of those viruses for testing.

The mechanism for updating the vaccines depends upon voluntary submission of nasal swabs from veterinarians to their state diagnostic laboratories or directly to the OIE (World Organization for Animal Health) international reference laboratories for equine influenza in England, Germany, and in Kentucky at the Gluck Equine Research Center.

Same-day test results are now possible for equine influenza using commercial rapid detection kits. The limiting factors are (1) expense: these tests cost $25-50 per swab and (2) the quality of the swab sample. Samples should be taken early in the disease process. Minimally use 6-inch Dacron swabs in pairs or alternatively uterine swabs (no 4-inch cotton swabs!).

See the Gluck Web site for further information about nasal swabbing and submission to the OIE reference laboratory at the Gluck Center.

Contact: Dr. Thomas Chambers, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Ky.

This is an excerpt from Equine Disease Quarterly, funded by underwriters at Lloyd's, London, brokers, and their Kentucky agents.

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Equine Disease Quarterly

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