Equine coronavirus (ECoV)

Veterinary advice should be sought before applying any treatment or vaccine.

Equine Coronavirus (ECoV)

Equine coronavirus (ECoV) is an infectious virus that has caused outbreaks of pyrogenic and enteric disease in horses throughout North America and Japan. Although initially thought to only affect foals, ECoV can cause disease in horses of all ages. Researchers at the University of California-Davis (UC Davis) veterinary hospital are uniquely qualified to diagnose and treat ECoV cases, with its multiple board-certified equine infectious disease specialists and a highly trained technical staff experienced with treating the disease. The facilities include an isolation unit to treat the horses without infecting other hospitalized animals, as well as an on-site laboratory to immediately perform diagnostic tests to confirm the disease and develop an appropriate treatment plan.

Clinical signs of ECoV

The most common clinical signs observed in horses infected with ECoV include:
  • Reduced or loss of appetite
  • Lethargy
  • Elevated rectal temperature (≥ 101.5°F)
Less common signs observed consist of:
  • Diarrhea: Ranging from soft-formed manure to acute, watery diarrhea
  • Colic
  • Aimless wondering
  • Headpressing
  • Recumbency
  • Seizures

How is ECoV Diagnosed?

ECoV can be detected in horses through:
  • PCR testing
  • ELISA testing
  • Viral isolation from the feces

How is ECoV Transmitted to Horses?

ECoV is shed in the feces of infected horses---starting from when they are initially infected with the virus and for up to 2 weeks after they recover. Other horses are infected by exposure to contaminated feces and it's surrounding environment. ECoV is spread very quickly, and often show signs of infection within 2-3 days after exposure.

What are the Treatment Options?

Treatment for ECoV infection is supportive, consisting of nonsteroidal anti-inflammatory (NSAID) drugs and sometimes intravenous fluids if horses become dehydrated. The disease course is short-lived, with clinical signs lasting for 1 to 4 days. The majority of horses recovery from the disease with general supportive care. Research conducted by UC Davis researchers have found that infection with ECoV has only been fatal to 8% of affected horses. Fatalities were the result of complications from endotoxemia, sepsis, or hyperammonemic encephalopathy.

Historic Outbreaks

In 2011, 132 racehorses housed with a total of 600 horses in Japan developed ECoV. Five separate outbreaks occurred at boarding stables in the United States affecting 75 horses between 2011 and 2012.


Reduced or loss of appetite
Fever (≥ 101.5°F)
Colic signs
Aimlessly wondering


  • ELISA testing
  • PCR testing: on fecal sample



Supportive care: Consisting of anti-inflammatory drugs such as NSAIDs and oral or intravenous fluids for maintaining hydration.



Good, most horses fully recovery with supportive care.

Scientific Research

General Overviews

Risk Factors

  • Lack of biosecurity procedures at horse facilities.

Causative agent