What is EHD?
click image to zoom EHD is a viral disease that has long been recognized as perhaps the most important infectious disease of white-tailed deer. In some years, there are significant numbers of death losses in deer populations due to EHD. Mule deer, antelope, and other deer species can also become affected. Cattle can become affected uncommonly. Clinical illness due to EHD is very rare in sheep and goats.
What are the signs of EHD in deer?
Usually the disease in deer develops so quickly that death losses are the only signs noted. If observed, affected deer may show signs of excessive salivation and nasal discharge, sometimes bloody in nature. Weakness and respiratory distress also are common. Hemorrhages throughout the entire body are often noted in the carcasses of deer that have died from EHD. Mortality rates are high.
Does EHD do the same thing to cattle?
No. The clinical disease in cattle is much milder and death losses are very infrequent. In the current outbreak, the most common sign noted in cattle is that of excessive salivation. Other signs noted include stiffness or lameness, a crusty peeling muzzle (Fig. 2), crusty skin on the teats (Fig. 3), fever, and a reluctance to eat.
What lesions are veterinarians seeing in these animals?
The most common manifestation of EHD in cattle in this South Dakota outbreak has been that of sores or ulcers in the mouth. Most of the time, these sores affect the upper mouth in the dental pad, near where the skin and the mucous membranes come together, or on the roof of the mouth. These sores can also be seen in the gums of the lower jaw (Fig. 1), or elsewhere in mouth. Cows may show redness, blistering, and leatheriness in their teats (Fig. 3). In some cases, sores or erosions have been noted in the feet where the skin meets the hoof (coronary band).
Is there any treatment for affected cattle?
There is no vaccine for the EHD virus itself in cattle. However, veterinarians working with affected herds have been prescribing anti-inflammatory medications and antibiotics in hopes of preventing problems with secondary bacterial infections that may crop up where the lesions occur. Providing a palatable, accessible source of feed and for these animals is important because of the pain that goes along with the sores in the mouth.
What is the outcome for affected cattle?
Reports from veterinarians are generally encouraging. Most of the affected cattle are recovering and beginning to eat.