Second Horse Tests Positive for EHV-1 in Alameda County

The California Department of Food and Agriculture (CDFA) has confirmed that a second horse at a property in Alameda County has tested positive for the neurologic form of equine herpesvirus-1 (EHV-1). The 18-year-old Quarter Horse mare exhibited a fever on April 2, following the diagnosis of a stablemate with equine herpesvirus myeloencephalopathy (EHM).

The case

This mare is among 75 horses that may have been exposed to the initial case. She is currently receiving supportive care at a veterinary hospital, while the property remains under quarantine. The Equine Disease Communication Center (EDCC), supported by industry donations, disseminates verified equine disease reports through its program, EDCC Health Watch. EHV-1 is highly infectious among horses and can lead to several health issues, including respiratory disease, abortion in pregnant mares, and EHM. Common early signs of infection typically include fever, which might pass unnoticed, along with symptoms such as cough, reduced appetite, and nasal discharge in younger horses.

Symptoms

For pregnant mares, symptoms often may not be evident until after an abortion occurs, which can happen anywhere from two weeks to a few months after infection. Neurological symptoms associated with EHM can develop days after initial fever, including incoordination, weakness, or paralysis. EHV-1 can be easily transmitted through direct contact with an infected horse, sharing equipment, or the contact surfaces of people who have interacted with an infectious horse. '

Prevention

To prevent the spread of this disease, it is crucial to implement routine biosecurity measures, including thorough hygiene and cleaning protocols. While current vaccines can potentially reduce the shedding of the virus, they do not provide protection against the neurologic variant. Hence, preventive measures are deemed the most effective strategy to control the disease.