The Michigan Department of Agriculture and Rural Development (MDARD) confirms a fourth horse has tested positive for the equine herpes virus (EHV-1). The horse is receiving veterinary care at a quarantined Saginaw County stable.
The index case was an eight-year-old barrel racer that tested positive for EHV-1 on March 19th. Despite treatment, the gelding was euthanized on March 21st. An infected horse remains stabled at a farm in Livingston County where the index case resided. It is also under quarantine. Two EHV-1 positive horses are stabled at the Saginaw County stable.
MDARD continues its investigation and is looking for horses that may have been exposed to the index case. In a release the department states, “at this time, we consider all horses that attended a March 7 event in Barry County to be at the highest risk of exposure.” Officials confirm from the progression of the outbreak that a secondary transmission is occurring. “Horses that attended the March 7 event may have been infected, shown only minimal signs of disease (fever, possibly a runny nose) and spread the disease to another horse.”
The EHV-1 virus spreads quickly from horse to horse, has a high morbidity rate, and can cause a wide range of symptoms, from a complete lack of clinical signs to respiratory problems. The neurologic form of EHV-1 can cause an acute paralytic syndrome, which has a high mortality rate.
While there are no travel bans for Michigan horses, the department urges horse owners to make informed decisions.
Horse owners that believe their horses may have been exposed are asked to help by voluntarily following the exposed-horse protocol. It includes isolating horses that may have been exposed, taking horses’ temperatures twice daily for 28 days, and calling the vet if a horse’s fever is over 101.5 or if they exhibit any symptoms of EHV-1.