By Jacquelyn Dietrich, BVSc
Coronavirus is an RNA virus that can cause respiratory and gastrointestinal problems in many species. In horses, Equine Coronavirus can result in gastrointestinal problems. Horses can be carriers of coronavirus showing no signs (subclinical), but have been found to shed the virus in feces. Horses that become infected and develop clinical signs can also shed the virus. Thankfully mortality (death) is rare in uncomplicated cases. Seroprevalence of equine coronavirus in the Unites States has been estimated at 9.3% (Kooijman et al., 2017). This means that Equine Coronavirus it ubiquitous within the horse population, many of which never show clinical signs.
How can my horse get Equine Coronavirus?
Transmission is through fecal-oral route, meaning that your horse becomes infected by ingesting infected fecal material.
How long does Equine Coronavirus survive in the environment?
Unfortunately, this is unknown. It’s important to practice good biosecurity, including disposing of shedding horses' manure in an area where no other horses can ingest it.
What is the seasonality?
Equine Coronavirus can occur anytime of year, however it is commonly seen in the colder months (December –May).
How soon will my horse show signs?
Every horse reacts different, but typically the incubation period is 2-4 days.
How long will my horse be shedding the virus?
The exact period a horse will shed the virus is still under investigation; however, horses have been found to shed the virus 5 – 21 days after being infected. Horses with no clinical signs and horses with clinical signs can both shed virus.
What are some signs to watch for?
Lack of appetite
Laying down frequently
Diarrhea (not always present in every case)
Low white blood cells
How can I confirm (diagnose) Equine Coronavirus?
Your veterinarian can confirm Equine Coronavirus by submitting a fresh fecal sample to a lab for testing (PCR test).
What is the treatment for Equine Coronavirus?
Supportive care based on clinical signs is the best treatment. For more severe cases, hospitalization for IV fluid therapy and treatment for any secondary infections may be required.
How likely is it that my horse will get better?
Very likely with supportive care and monitoring for secondary infections.
How can I prevent my horse from getting Equine Coronavirus?
The best method for prevention is good sanitation of facilities, disposing of manure in areas horses can’t be infected, and other good biosecurity practices. Make sure manure cannot contaminate pasture, paddocks, stalls, and drinking water.
What about other animals?
Equine Coronavirus is a species-specific virus, meaning that is passed from horse to horse only.
What do you mean by “good biosecurity”?
Wash hands frequently, especially before and after handling each horse.
Don’t share equipment and grooming supplies, especially with infected or potentially infected horses.
Isolate horses that start to show clinical signs. Do not walk horses around facilities that have been showing clinical signs or that was in close proximity to infected horses.
When cleaning stalls, clean infected and potentially infected stall last. Always handle infected or potentially infected horses last. This way stalls of healthy animals cannot come into contact with any fecal material from horses shedding the virus. Manure should be disposed in an area where horses can not reach (ingest).
Reduce movement of horses in and out of facilities with horses positive for virus. Horses that are moved from a facility with horses positive for virus should be isolated for 3 weeks. A fecal sample should be taken to confirm no virus is present before removing horse from isolation.
Disinfect anything that comes into contact with an infected horse. Remember, you must remove any organic mater (dirt, feces, etc) before using a disinfectant. This is because disinfectant becomes inactive when in contact with organic matter. Talk to your vet about the appropriate disinfectant to use for different outbreaks. For coronavirus, bleach, povidone iodine, and chlorhexidine gluconate are common disinfectants that have been shown to be effective against coronavirus. Chlorhexidine (Nolvasan) is a common product that can be purchased in many stores (feed stores, Target, drug stores, etc) can is effective against the virus even if organic matter is not completely removed.
Equine Coronavirus is not a reportable disease in the state of California, as it is much less of a concern due to its high prevalence with low morbiditiy and mortality rates (meaning many horses show no signs of disease and few horses thankfully have furthering clinical signs/secondary disease/issues leading to death) compared to other contagious diseases horses have the potential for acquiring. Our state veterinarian says, "Currently, coronavirus is not a reportable disease in the state of California. Therefore, the state lacks authority to take regulatory action such as quarantine for confirmed cases of coronavirus. As always biosecurity measures, such as isolating horses with clinical signs and avoiding sharing of equipment, should be immediately implemented when there is any evidence of disease on the premises."
Call Steinbeck Peninsula Equine Clinics with any concerns or questions.
Equine coronavirus is NOT the same as the strain of coronavirus referred to as COVID-19 that is currently in the news (2020) associated with a world-wide outbreak, and is NOT considered as having a risk of transmission to humans. For more information, check out an article called "Can Pets Contract Coronavirus from Humans or Vice Versa" written by Dr. Niels Pedersen at UC, Davis, School of Veterinary Medicine and What is Equine Coronavirus? from thehorse.com.
Below are some excellent resources for more information on Equine Coronavirus and biosecurity practices:
Pusterla, N., Mapes, S., Wademan, C., White, A., Ball, R., Sapp, K., . . . Magdesian, K. (2012). Emerging outbreaks associated with equine coronavirus in adult horses. Journal of Equine Veterinary Science, 32(10). doi:10.1016/j.jevs.2012.08.088
Pusterla, N., Vin, R., Leutenegger, C., Mittel, L., & Divers, T. (2018). Enteric coronavirus infection in adult horses. The Veterinary Journal, 231, 13-18. doi:10.1016/j.tvjl.2017.11.004
(2017). Prevalence of Fecal Shedding of Equine Coronavirus in Hospitalized Horses. Equine Veterinary Education, 29, 8-9.