By Richard F. Randle, University of Nebraska Extension Beef Cattle Veterinarian
In the last few weeks, the Nebraska Department of Agriculture has investigated multiple cases of cattle with severe oral, nasal and ocular lesions. Because the lesions look very similar to Vesicular Stomatitis and/or Foot and Mouth Disease, foreign animal disease investigations were performed with submissions to the Foreign Animal Disease Diagnostic Laboratory at Plum Island, NY. The investigation revealed 10 confirmed cases of EHD (Epizootic Hemorrhagic Disease).
Epizootic hemorrhagic disease (EHD) is a disease of great concern for deer in North America. The epizootic hemorrhagic disease viruses are widespread in white-tailed deer and periodically cause serious epidemics in wild populations. In years of high incidence, the disease can cross over into cattle by insect vectors, especially biting midges, gnats, and mosquitoes.
The emergence of this disease is not new. Confirmed cases of epizootic hemorrhagic disease have occurred in North American cattle, in conjunction with epidemics in deer for several decades. The number affected can be as high as 5%, but most cattle recover within a few weeks. Symptoms in cattle include fever, swollen eyes, ulcers on the mouth, lameness and labored breathing. Deaths are uncommon. Severe erosions and sloughing of the oral and nasal mucosa can cause extreme dehydration, so mortalities are seen during high ambient temperature situations.
Most infections with the North American strains of EHD appear to be subclinical and seropositive cattle may be common in some regions. There is evidence to suggest that pregnant cows may experience reproductive problems; abortions and fetal resorptions are commonly seen.
Cattle showing signs of oral or nasal lesions should be examined by a veterinarian immediately.