A Survey of Brucellosis in White-Tailed Deer in Missouri

Abstract

Previous studies of brucellosis (also known as Bang's disease and contagious abortion) in big-game animals have revealed its occurrence in bison (Creech, 1930; Rush, 1932; Tunnicliff and Marsh, 1935), in elk (Allred, 1947; Lee and Turner, 1937; Murie, 1951; Rush, op. cit.; Tunnicliff and Marsh, op. cit.), in moose (Fenstermacher and Olsen, 1942; Jellison, Fishel and Cheatum, 1953), and in whitetailed deer (Bolin, Goldsby, Rheault and Eveleth, 1949). The few mule deer and pronghorn antelope tested were not infected with brucellosis (Bolin and Eveleth, 1951; Ryff, 1951). Only in bison has a high incidence of brucellosis been reported (Tunnicliff and Marsh, op. cit.), and only in elk has the disease been reported to have had a deleterious effect on herd productivity (Murie, op. cit.). Brucellosis appears to be rare in white-tailed deer. Blood sera from 436 white-tailed deer from North Dakota were tested by Bolin, Goldsby, Rheault and Eveleth (op. cit.). Only one animal was found to be infected. They also report the detection of one brucellosisinfected deer among four tested by a private veterinarian in North Dakota. In a later study (Bolin and Eveleth, op. cit.), blood sera from 70 more whitetails were tested and found negative for brucellosis. Fenstermacher, Olsen and Pomeroy (1943) tested blood sera of six Minnesota whitetails for brucellosis and tularemia, with negative results. Recent work in Ohio (Edgington, 1951) revealed no brucellosis in the 210 deer tested there. Whitlock (1949) found no brucellosis in whitetails in Michigan. While the results of these surveys were reassuring, the possibly serious effects brucellosis might have on deer herd productivity, and the potential danger of spreading the disease, if it was present, to domestic livestock, made it important that we ascertain whether our deer were infected with brucellosis. Recent increases in the size of both the deer and cattle herds in Missouri made the problem an immediate one. Blood samples have been collected from white-tailed deer (Odocoileus virginianus) killed during the past four deer seasons (1950-1953) in Missouri. Samples were collected by Conservation Commission biologists from deer brought to deer-checking stations by hunters. Nearly all deer are eviscerated when brought to checking stations, so blood can be obtained only from the visceral cavity of freshlyeviscerated deer. No attempt was made to collect blood from deer whose visceral cavities were obviously contaminated with intestinal contents, urine or water, and in many cases no blood was available. In spite of adverse conditions, a large number of blood samples was collected each year, and, although most samples showed some degree of hemolysis, nearly all were in satisfactory condition for testing. During the four-year study, blood samples were collected from 1,019 deer, killed in 17 counties, mainly in southern and east-central Missouri. A total of 996 samples yielded sufficient sera in adequate condition to test. These samples were collected from 352 adult males, 234 adult females, 153 fawns, and 257 deer of unknown age, about half of which were females. All blood samples were delivered to the State and Federal Cooperative Bang's Testing Laboratory in Jefferson City, Missouri, where they were centrifuged and the sera tested for brucellosis. Deer serum was tested exactly as cow serum is, using the standard plate agglutination test, with Bureau of Animal Industry Brucella abortus antigen. In 1950, 1951, and 1952, all sera were tested first at a dilution of 1 to 50. Where clear-cut negative results were not obtained, sera were centrifuged a second time and tested at dilutions of 1:50, 1:100, 1:200 and 1:400. In 1953 sera were tested first at a 1:42 dilution. If further testing was indicated, sera were again centrifuged and tests were set up at dilutions of 1:50, 1:100 and 1:200.