Epizootic hemorrhagic disease (EHD)
(NY) Epizootic hemorrhagic disease (EHD) was diagnosed in four cows on a small dairy farm in NY. The cows presented with fever, decreased appetite, drooling, swollen coronary bands and lameness. Erosions and intact vesicles were noted on oral examination. Differentials included foot and mouth disease (which, as a foreign animal disease, had to be ruled out first), malignant catarrhal fever, bluetongue and parapox. This marks the first outbreak of clinical EHD in non-cervids in NY state in several years.
Epizootic hemorrhagic disease was strongly considered in this herd due to a high mortality outbreak of EHD this summer and fall in both captive and wild white-tailed deer (WTD) in NY that was closely monitored by the Cornell Wildlife Health Lab at the AHDC. For more information on EHD in WTD of NY state, visit https://cwhl.vet.cornell.edu/article/epizootic-hemorrhagic-disease-white-tailed-deer-updated.
The AHDC offers an EHD PCR. Appropriate antemortem samples include a swab of vesicular lesion in a sterile container with 0.5 ml saline or viral transport media, or 2 mL of EDTA or citrated whole blood. Appropriate post-mortem samples include spleen, lymph node, lung or a swab of vesicular lesion as described above. An agarose gel immunodiffusion (AGID) test is available to detect antibodies to EHD, but can cross react with bluetongue virus. An EHD serum neutralization test can be performed to determine serotype. Testing for types 1, 2 and 6 is available at the AHDC. This test requires 1 mL of serum in a red top tube. All samples should be shipped in an insulated container, overnight with ice packs.
Cattle typically experience subclinical infections with EHD. There have been outbreaks in cattle in Asia with signs of fever, lethargy and salivation. Yaks and bison can also present with clinical signs. Transmission occurs via Culicoides midges, and most cases therefore are seen in late summer and early fall. Prevention is focused on limiting exposure to Culicoides. There are currently no vaccines commercially available.
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