Purdue News
Purdue News
September 6, 1996
Kenyon, a large-animal specialist in Purdue's School of Veterinary Medicine, and federal veterinarians have spent a week surveying affected herds, and tests indicate the disease is likely to be epizootic hemorrhagic disease (EHD). While EHD is not fatal to cattle, it has caused the animals some extreme discomfort, Kenyon said. Affected cattle lose condition rapidly. Various treatments have been tried, including antibiotics, steroids, and vitamin E and selenium injections. Cattle recover in five to 10 days with or without treatment.
Symptoms include fever, anorexia, lameness in all four feet, crusty nose, slobbering or drooling, fetid breath and lesions on the mouth and tongue. Cases have been seen Perry, Spencer, Crawford, Washington, Orange and Dubois counties.
There are no practical precautions available to protect cattle, Kenyon said, but the disease seems to affect only 5 percent to 10 percent of a herd for a relatively short time, and recovery is rapid. Because affected cows are reluctant to walk and may refuse to rise, Kenyon said it is essential that they be provided with adequate water and soft palatable feed. Cows may not eat hay but often will eat concentrate feeds, but Kenyon cautioned against the risk of overfeeding cattle with concentrates and advised cattle owners to seek veterinary advice on the diagnosis of this disease and care of affected animals.
Blood and tissue samples from some of the cattle have been shared between the Animal Disease Diagnostic Laboratory at Purdue and the U.S. Department of Agriculture animal laboratory at Plum Island, N.Y. Of the animals that have been tested, most have antibodies to both epizootic hemorrhagic disease virus and bluetongue virus. Further testing is being done to distinguish between the two viruses, which are very closely related. Bluetongue virus also infects sheep, but EHD does not.
Because the clinical description fits previous reports of EHD in cattle and there are no current reports of sheep being affected, it seems most likely that these cases are epizootic hemorrhagic disease. Confirmation of the diagnosis would depend on the isolation of virus from affected cattle or the demonstration of a rising level of antibodies in acute and convalescent blood samples.
Laboratory tests have ruled out many more serious diseases such as vesicular stomatitis, foot-and-mouth disease, and malignant catarrhal fever, but because EHD may be confused with these viruses, it is important that suspicious cases continue to be reported, Kenyon said. "It would be disastrous if the early cases of an outbreak of vesicular stomatitis were missed because it was assumed that any similar cases were EHD," he said.
EHD also may be confused with bluetongue, which has similar symptoms and is spread the same way. Transmission is by certain species of midges or gnats, and cattle infections with EHD may occur almost simultaneously over a wide area. Previous reports of EHD in cattle have been concentrated along watercourses and end with the appearance of cold weather.
EHD virus can cause a fatal disease in white-tail deer, but most cases of EHD in cattle in other states have not been associated with outbreaks of the disease in deer. There have been no reports of a kill-off of wild deer in the area.
ACS code/960830 AgR Kenyon/9609f1
Source: Simon Kenyon, (317) 494-0333; home, (317) 876-7559; e-mail, kenyons@vet.purdue.edu
Writer: Chris Sigurdson, (317) 494-8415; home, (317) 497-2433; e-mail, sig@ecn.purdue.edu
