Equine Influenza: Vaccinations Begin

According to information from the New South Wales (NSW) and Queensland, Australia, governments, vaccination has begun in specific areas to try and contain the outbreak of equine influenza in that country.

As of Sept. 28, New South Wales reported 2,653 infected properties, 323 dangerous contact properties, and 356 suspect properties.

As of Sept. 29, Queensland reported 440 infected properties. Equine influenza is reported as still contained to the "Red Zone" in the state's southeast region, which borders New South Wales.

The government's vaccination program to assist in containment and eradication starts today (Sept. 29) in New South Wales and Queensland. In New South Wales, about 300 horses in a 10km wide strip just north of Mittagong will be the first vaccinated as part of the “buffer zone” phase in the campaign to eradicate horse flu.

The Queensland Department of Primary Industries and Fisheries Biosecurity Chief Veterinary Officer Ron Glanville said the original strategy of establishing a series of smaller buffer zones had been revised after a number of outbreaks in new locations in South East Queensland were confirmed earlier this week.

"In the first shipment of vaccination vials, Queensland has been allocated 9,240 vaccination shots," he said. "Vaccination will be targeted in very specific areas. We are not planning a general vaccination of horses in the Red Zone in the short term. We are conscious that many horse owners desire immediate vaccination of their animals, but initial supplies are limited and the priority distribution of the vaccine is being determined in consultation with horse industries.

"The first priority will be those large groups of horses that make a significant contribution to the economy and people's livelihoods," he added. "This means racing precincts, spelling farms and other locations where high performance horses are kept. All vaccinations will be delivered by private veterinarians trained by DPI&F."

New South Wales government press releases stated that while there were additional infected properties from Thursday to Friday (Sept. 27-28), the new properties are still occurring within existing Red and Purple Zones, which is where influenza is known to exist. Further cases are predicted to occur around existing infected properties and suspect properties, where there are very high horse densities. The press releases said adjustments in zone interfaces have been made and will continue as cases are further monitored and resolved.

"We are considering an expansion of the green zone and for conversion of some red areas to purple zones," noted the press release. "The disease containment situation remains encouraging and there is still reason to be optimistic about the prospects for eradication, although a sustained response effort will be required over the next six or more months to achieve this goal. Epidemiologists are continuing to trace the epidemiology of the outbreak to determine source and potential disease spread of outlying infected properties."

Many Australian horse owners have asked questions to the government about vaccination, following are those questions and answers:

Now the vaccine is available, why not vaccinate everything?
Vaccination is not 100% effective. Horse populations that are vaccinated still have epidemics because the viral strains change and vaccines do not stop a horse from being infected or stop virus excretion. The horses that originally brought the virus into the country were vaccinated.

If the major cost of EI is to racing, why not just vaccinate the racehorses?
Vaccinating only the racehorses is not going to protect the racing industry from outbreaks that stop racing. In Australia only 20% of horses are in the racing sector. If it was voluntary for the remaining 80% of all horses to be vaccinated, we could not be sure that they were effectively vaccinated.

The vaccine contains a live virus--will my horse get influenza because of the vaccination?
The vaccine contains genetically modified canary pox virus. It does not survive in the horse, but produces enough components of the equine influenza virus to produce an immune response against equine influenza. The vaccine will not produce equine influenza disease.

The disease seems to last for about a week; how long is my horse infective for other horses?
Tests on infected horses that have been monitored every day indicate that horses excrete virus for up to three weeks after infection. This means that excellent personal biosecurity has to be maintained even when the horses seem to have recovered. We cannot afford any continuation of infection. The disease is now burning out in the first areas affected--let’s keep up the control effort.

About the Author

Kimberly S. Brown

Kimberly S. Brown was the Publisher/Editor of The Horse: Your Guide To Equine Health Care from June 2008 to March 2010, and she served in various positions at Blood-Horse Publications since 1980.

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