The recent increased incidence of equine influenza in the United States and abroad necessitates implementation of prevention and control strategies to protect the health of the equine population.
Sunlight on horse in stall- the best disinfectant
The increased incidence of equine influenza necessitates implementation of prevention and control strategies to protect the health of the equine population.
© 2016 by Stacey Bates
Although vaccination plays an important role, it should not be relied on athe sole preventative. Similar to other influenza viruses, equine influenza virus mutates over time and vaccines must be periodically updated to keep current with circulating viruses.
Horses that have been vaccinated in accordance with manufacturer’s label instructions and the recommendations of American Association of Equine Practitioners may be protected against equine influenza.
Studies suggest the use of the modified live intranasal vaccine in previously unvaccinated horses can provide protection within five days of primary administration.
However, no vaccine is 100% effective. Investigations into recent cases indicate that vaccinated horses can develop mild clinical signs of short duration, whereas unvaccinated horses are more severely affected and more likely to develop secondary pneumonia and pleuritis.
Implementation of biosecurity measures is essential to protecting the health of horses during influenza season. As influenza virus is spread most readily through nose-to-nose contact, it is critical to limit horse-to-horse contact and require strict isolation of new arrivals and sick horses.
Infected animals should be kept at a minimum distance of 50 yards from healthy horses. If no suitable permanent isolation stable is avail-able, then designate an area on the property where a temporary isolation structure can be erected.
When no appropriate onsite isolation areas are identified, consider appropriate off-site isolation facilities such as vacant barns, empty fair or event grounds, or veterinary clinics.
To prevent virus transmission, designate personnel and equipment to the isolation area. Disposable coveralls, gloves, and boot covers should be used when handling horses in isolation.
Personnel who must care for animals both in and outside of isolation should handle healthy animals first and isolated animals last. Individuals caring for exposed or infected horses should utilize alcohol-based hand sanitizers after handling all horses.
Influenza virus can be inactivated by exposure to sunlight or by use of disinfectants.
The virus can remain viable for up to 2 days on contaminated surfaces, specifically solid surfaces of stall door latches. Thus, any shared equipment should be thoroughly cleaned and disinfected between uses.
The critical factor in controlling and preventing the spread of influenza virus is monitoring the health of all equids.
Monitoring includes taking body temperatures twice daily and recording all clinical observations. Only healthy horses, which have been monitored, should be permitted to leave the premises.
Any horse showing clinical signs of respiratory disease should be immediately isolated and examined by a veterinarian. Horses should remain isolated until they’re clinically healthy and no longer shedding virus.
As respiratory shedding of the influenza virus can persist for 7-10 days post-infection in a naïve animal, horses should remain isolated for a minimum of 14 days.
Appropriate use of vaccination and implementing biosecurity measures are critical to protecting the equine industry from highly contagious equine influenza virus.
Article by Katie Flynn, BVMS, California Department of Food and Agriculture, Animal Health Branch and published in Equine Disease Quarterly April 2019