Epizootic Hemorrhagic Disease (EHD) has been diagnosed in yak at two locations in Larimer County and one location in Alamosa County; these three cases have been confirmed by laboratory diagnostic tests at Colorado State University. 

“We have not had confirmed positives of EHD in recent years but this is the time of year, in late summer and early fall, that we would expect to see cases,” said State Veterinarian Dr. Keith Roehr.

EHD is a viral disease that affects deer, cattle and, most recently, yak.  Signs of EHC include fever, loss of appetite, weakness, respiratory distress, and swelling of the tongue, and erosive lesions in the mouth.  The disease cannot be transmitted by direct contact and is spread by insects, most commonly midges or gnats.

“Occurrence of the disease will diminish as hard frosts kill the virus and virus carrying insects.  Until then, it is important for producers to practice insect control to help prevent the spread of the disease,” said Roehr.

Recently, cases in deer and cattle have been diagnosed in Nebraska and South Dakota. The deer population in Nebraska has seen a significant number of cases this year. Further investigation is ongoing to determine if the outbreak in Colorado may be tied to the Nebraska cases. 

The EHD virus does not affect people. While there is no direct treatment for the EHD virus, supportive care is important to enable animals to recover from the disease.