Deadly New Insect-Borne Virus Targeting Arizona Wildlife

Aug 6, 2018

EHD is transmitted most often by biting midges, including Culicoides variipennis.
Credit Tom Murray

Arizona deer and elk are fighting a deadly new insect-borne virus this monsoon season. KNAU’s Aaron Granillo reports.


About 30 deer have died since the new strain of epizootic hemorrhagic disease was detected in the West for the first time last year.

EHD 6 is spread through flies and midges, and only infects animals, including deer, elk, and in some cases, bighorn sheep and pronghorn antelope. 

“Last year, we saw deer behaving abnormally. Circling and being very depressed," says Anne Justice-Allen, a veterinarian with Arizona Game and Fish Department. "It wasn’t a large number of deer, but it’s something that certainly catches our eye.” 

Allen says weather patterns and other climatic factors brought the disease to Arizona, hundreds of miles from where it was first detected in the Midwest.

EHD 6 is now here to stay, but Allen says animals can eventually adapt and develop immunity.