New Zealand Neurologic EHV-1: 15 Horses Affected

New Zealand Neurologic EHV-1: 15 Horses Affected

Neurologic EHV-1

Photo: George P. Allen, PhD

Fifteen horses on a single Cambridge-area stud farm have been affected in New Zealand's first neurologic equine herpesvirus-1 (EHV-1) outbreak, according to a Feb. 27 statement from that country's Ministry of Primary Industries (MPI).

Of those horses, seven have been euthanized and eight are recovering, the statement said. Additionally, another horse on the farm was euthanized for reasons unrelated to the outbreak, the statement said.

"The stud farm still remains under voluntary quarantine," the statement read. "MPI is in regular contact with the stud farm and the farm’s veterinarian. MPI is now working with the affected stud and NZEHA (the New Zealand Equine Health Association) on a plan for removing quarantine restrictions."

The MPI encouraged owners to be alert for signs of disease in their horses and to contact their veterinarian if concerns arise. They also cautioned that some other diseases—including West Nile virus; Eastern, Western, and Venezuelan equine encephalitis; and hendra virus, among others—can cause neurologic clinical signs in horses. In the statement, officials asked veterinarians to call the MPI's Exotic Pest and Disease Hotline if they find any unusual equine neurologic cases.

Additionally, the MPI statement reported that a yet unpublished study conducted at Massey University collected and evaluated trigeminal ganglia (a mass of nerve tissue associated with the face and head) and retropharyngeal lymph nodes (located in the throatlatch area) from the heads of 52 horses processed at a New Zealand abattoir (slaughterhouse) in February 2012.

"The sequencing found that both EHV-1 genotypes (the neuropathogenic D752 and wild-type N752) were present in the trigeminal ganglia of a Thoroughbred horse; this suggests that the horse was latently infected with both genotypes," the statement read. "This finding suggests that the neuropathogenic D752 strain has been present in the New Zealand horse population for at least two years. Further testing of the samples from this study is still in progress."

Health Alert: Equine Herpesvirus (EHV)

Although it's not transmissible to humans, EHV-1 is highly contagious among horses and camelids and is generally passed from horse to horse via aerosol transmission (when affected animals sneeze/cough) and contact with nasal secretions on objects such as feed buckets, grooming supplies, humans, and other infected animals. The disease can cause a variety of ailments in equids, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and myeloencephalopathy.

Myeloencephalopathy is characterized by fever, ataxia (incoordination), weakness or paralysis of the hind limbs, and incontinence. Should a horse that potentially has been exposed to EHV-1 display any of the aforementioned clinical signs, call a veterinarian to obtain samples and test for the disease. will continue to provide updates as more information becomes available.

About the Author

Erica Larson, News Editor

Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

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