Chronic Wasting Disease
Chronic Wasting Disease (CWD) is a transmissible spongiform encephalopathy (TSE) disease that affects cervids. The causative agent of TSE diseases are prions, or proteins that fold abnormally and become infective and ultimately fatal. CWD was first detected in the 1960s in mule deer housed in research facilities in Colorado. By the 1980s, it was detected in free-ranging elk. To date, chronic wasting disease has been detected in 30 states in the U.S. and several Canadian provinces. As the name implies, signs of CWD include chronic weight loss leading to emaciation, abnormal behavior, difficulty walking or standing, and affected animals often have poor quality coats. SCWDS conducts testing for CWD in cervid samples submitted from members agencies throughout the southeastern United States. Since CWD can have an incubation period of up to two years, early detection of cases is essential to limiting the spread of the disease.
If you encounter wild cervids exhibiting signs consistent with CWD infection or for more information, please contact your state wildlife agency.
Hemorrhagic disease (HD) is a major disease complex of wild ruminants in North America. It consists of the Orbiviruses epizootic hemorrhagic disease virus (EHDV) and Bluetongue virus (BTV) which are transmitted by the insect genus Culicoides, commonly known as biting midges. There are two main forms of HD: acute and chronic disease. The acute form rapidly progresses and lethargy, lameness, hemorrhaging of oral, thoracic, and gastrointestinal systems can lead to heavy mortalities. The chronic form typically presents as lameness, sloughing of hoof walls that can lead to secondary infections, and emaciation due to rumen ulcers and loss of rumen papillae which impedes digestion and absorption of nutrients. There is a seasonality of HD outbreaks corresponding with the emergence of Culicodes midges in early spring through fall, but regional patterns can vary tremendously: infrequent but severe mortality can occur in more northern latitudes while frequent, mild to asymptomatic infections are common in more southern regions. In areas where mortality is severe, HD can drastically affect population levels, but in areas where the chronic form is more prevalent, population-level impacts are likely minimal. SCWDS conducts testing for HD in cervid samples submitted from members agencies throughout the southeastern United States. Historically, two serovars of EHDV (EHDV-1 , 2) and five serovars of BTV (2, 10, 11, 13, 17) were predominant in North America; however, recent diagnostic serology testing has determined that multiple EHDV and BTV serovars are associated with HD outbreaks in wild cervids, particularly EHDV-6.
If you notice a wild cervid with signs consistent with HD, please notify your state wildlife agency.
More information regarding HD in wild cervids
Herd Health Assessment
Annually in the fall, various state agencies participate in the SCWDS Herd Health Assessment of white-tailed deer. This is a long-term project which began in the 1960s to determine the role of wild deer in pathogen transmission to domestic livestock species. The protocol includes serological, parasitological, and histological evaluation of five white-tailed deer collected from a specific location during the fall. Serum samples are screened for the following pathogens: Leptospirosis spp. serovars, Brucella spp., Epizootic Hemorrhagic Disease Virus, Bluetongue Virus, Infectious Bronchitis Virus, Bovine Viral Diarrhea, and Parainfluenza-3 Virus. Parasitology analyses include screening for various ectoparasites and endoparasites that can cause pathogenesis in wild deer. Additionally, abomasum parasite counts and speciation are performed to evaluate deer herd density. Histological analysis of tissues can serve to identify tissue and organ abnormalities in wild deer.
The results provided from this analysis help guide management decisions of white-tailed deer for a particular area. Repeated collections from the same area allow managers to evaluate management activities and allow for the assessment of herd trends. Additionally, serum and tissues collected from herd health submissions are banked in long-term storage for future analysis. It also serves as a management tool for member agencies.