RED DEER – Two troublesome diseases afflicting horses may be relieved by new vaccines.
Strangles and equine influenza are two highly infectious conditions that can run rampant through a herd, equine specialist Hugh Townsend of the University of Saskatchewan told a recent horse breeders conference in Red Deer.
Pinnacle, a modified live intranasal vaccine developed by Ft. Dodge, has been available for two years to treat strangles, which was particularly severe in Alberta and Saskatchewan this year.
“This is a very smart organism and it is very hard to beat,” said Townsend.
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Strangles causes severe lesions and in the worst cases, disability or death. It seems to afflict mostly young horses. There is fever, nasal discharge and lymph nodes under the jaw swell. Some horses may develop abcesses in the brain, thorax and abdomen.
There may be purpura hemorrhagica or leaky blood vessels and swollen legs. Horses that recover have natural immunity for six to 12 months after the infection occurred.
Before the vaccine was developed, limited protection was provided with an intramuscular vaccine developed about 15 years ago.
The intranasal medication is a modified live vaccine that stimulates the immune system enough to prevent some of the more serious effects.
Modified live vaccines that have been cultured and cannot cause the disease do provide better immunity than killed vaccines.
There are also new and improved vaccinations for influenza.
Two studies showed Encevac TC-4 by Bayer and Fluvac EWT Plus by Ayerst are promising medications.
Townsend was involved in a study that found some horses do not respond and do not develop an adequate immune response even after vaccination.
Research has also found four vaccinations over a period of six months are necessary to provide a sufficient immune response to the flu. Horses may still catch the disease but symptoms are less severe.
– Duckworth
