State Veterinarian Dustin Oedekoven says more than 40 cattle herds in southeastern South Dakota have been reported with signs of illness that include fever, ulcers in the mouth, excessive salivation and lameness when walking.
Oedekoven says laboratory tests indicate some ill cattle have been exposed to epizootic hemorrhagic disease, known as EHD. He says the hemorrhagic disease rarely affects cattle, but the state's deer population is currently experiencing an epidemic.
The EHD virus is spread by biting midges. Oedekoven says death is rare in affected cattle herds, but insect control helps prevent the risk of infection in cattle. He says the virus in not known to infect people.
Oedekoven says farmers and ranchers who notice signs of illness in their cattle should contact a veterinarian immediately.