APPENDIX C
OTHER DISEASES IN GYA WILDLIFE

Bacterial diseases other than B. abortus are present in the GYA and do infect bison and elk. Those and other species also can be affected by parasitic and viral diseases. It is useful to examine some aspects of these diseases with what is known of infection and transmission of brucellosis. As is the case with brucellosis, research and data are lacking in wildlife for many of the diseases discussed below.

BACTERIAL DISEASES

Tuberculosis

Tuberculosis caused by Mycobacterium bovis is a chronic bacterial disease that has tissue changes similar to those in brucellosis. Tubercular lesions develop in lungs and intestine, and transmission appears to occur by inhalation or by ingestion of contaminated material. Unlike brucellosis, lesions have not been found in the reproductive tract of bison or elk with tuberculosis, and placentae have not been shown to be infected. Although tuberculosis rarely has been diagnosed in free-ranging bison or cervids in North America, it is common in bison in Wood Buffalo National Park in Canada (Tessaro 1987). Tuberculosis has recently been reported in elk in Manitoba and in mule deer in south-central Montana (Rhyan et al. 1992). Disease and tissue lesions in asymptomatic animals are uncommon, and the risk of transmission of tuberculosis in bison and elk appears to be considerably lower than that of brucellosis in these species.

Previous reports of tuberculosis in free-ranging animals have been in white-tailed deer (Odocoileus virginianus) in New York, Michigan, and Ontario. In the Canadian National Buffalo Park near Wainwright, Alberta, gross lesions consistent with tuberculosis have been found in elk (Cervus elaphus nelsoni), mule deer (Odocoileus hemionus), and moose (Alces alces) (Tessaro 1987).

The presence of tuberculosis in captive herds of deer and elk in several states and provinces in North America might constitute a source of M. bovis for wild species. In each of the above cases, M. bovis-infected cattle, captive



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APPENDIX C OTHER DISEASES IN GYA WILDLIFE Bacterial diseases other than B. abortus are present in the GYA and do infect bison and elk. Those and other species also can be affected by parasitic and viral diseases. It is useful to examine some aspects of these diseases with what is known of infection and transmission of brucellosis. As is the case with brucellosis, research and data are lacking in wildlife for many of the diseases discussed below. BACTERIAL DISEASES Tuberculosis Tuberculosis caused by Mycobacterium bovis is a chronic bacterial disease that has tissue changes similar to those in brucellosis. Tubercular lesions develop in lungs and intestine, and transmission appears to occur by inhalation or by ingestion of contaminated material. Unlike brucellosis, lesions have not been found in the reproductive tract of bison or elk with tuberculosis, and placentae have not been shown to be infected. Although tuberculosis rarely has been diagnosed in free-ranging bison or cervids in North America, it is common in bison in Wood Buffalo National Park in Canada (Tessaro 1987). Tuberculosis has recently been reported in elk in Manitoba and in mule deer in south-central Montana (Rhyan et al. 1992). Disease and tissue lesions in asymptomatic animals are uncommon, and the risk of transmission of tuberculosis in bison and elk appears to be considerably lower than that of brucellosis in these species. Previous reports of tuberculosis in free-ranging animals have been in white-tailed deer (Odocoileus virginianus) in New York, Michigan, and Ontario. In the Canadian National Buffalo Park near Wainwright, Alberta, gross lesions consistent with tuberculosis have been found in elk (Cervus elaphus nelsoni), mule deer (Odocoileus hemionus), and moose (Alces alces) (Tessaro 1987). The presence of tuberculosis in captive herds of deer and elk in several states and provinces in North America might constitute a source of M. bovis for wild species. In each of the above cases, M. bovis-infected cattle, captive

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elk, or bison herds were in the vicinity and were considered likely sources of sporadic tubercular infections in the wild ungulates. Recently, tuberculosis caused by M. bovis was diagnosed in an infected captive herd of elk near the northern border of YNP; the disease occurred near free-ranging northern YNP elk (Thoen et al. 1992). On the basis a single tuberculin skin test, the herd had 28 positive reactors; at necropsy, one animal had tuberculous lung lesions from which M. bovis was isolated. A followup disease survey of free-ranging, hunter-killed elk from three areas of YNP revealed no tubercular lung lesions in 289 elk collected between December 1991 and January 1993. Neither M. bovis nor M. paratuberculosis was cultured from specimens. Antibodies to B. abortus were found in serum samples from 0%, 1%, and 1% of elk from the three areas sampled (Rhyan et al. 1997). If tuberculosis is suspect in bison or elk, the medial and lateral retropharyngeal, mediastinal, and tracheobronchial lymph nodes should be collected and examined bacteriologically and histologically. M. avium can cause tuberculosis in deer but is most often isolated from deer that have no lesions of tuberculosis (Rhyan et al. 1997). Paratuberculosis Paratuberculosis (Johne's disease), a chronic intestinal infection of cattle and other ruminants, is a progressive granulomatous enteritis that is seen clinically as severe diarrhea and wasting. Paratuberculosis has been reported in free-ranging ungulates, including bighorn sheep (Ovis canadensis), mountain goat (Oreamnos americanus), tule elk (Cervus elaphus nannodes), axis deer (Axis axis), and fallow deer (Dama dama). Paratuberculosis has been reported in red deer and has been reproduced experimentally in elk, mule deer, and white-tailed deer (Williams et al. 1983). The absence of clinical paratuberculosis and the negative culture results for M. paratuberculosis are consistent with the lack of reports on paratuberculosis in elk in national parks other than YNP (Rhyan et al. 1997). The risk of transmission of paratuberculosis in bison and elk appears to be low, although it does occur. Leptospirosis Leptospirosis affects the liver and kidney. Bacteria replicate in the renal

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tubules and are released into urine, and new animals are infected when they drink contaminated water. Serologic evidence of leptospirosis has been found in elk and in bison of YNP (Taylor et al. 1997). The mechanisms and risk of transmission in elk is not known. Abortion is associated with leptospirosis in most mammals, but the incidence of leptospiral abortion in elk and a role in transmission through genital infection are not known. In the southwestern United States, serologic evidence of leptospirosis suggests that deer are a natural host for leptospires. Anthrax Anthrax is acquired from ingestion or inhalation of bacterial spores in soil or on contaminated vegetation and debris; it is not transmitted directly from animal to animal and does not specifically involve the reproductive tract. Anthrax appears clinically as peracute septicemia in bison. Free-ranging bison with anthrax have been reported, and sporadic epizootics have occurred at various North American sites, including one outbreak in which 1,110 bison died. The causal organism, Bacillus anthracis, appears to be moved from endemic areas in Louisiana and Texas by waterfowl. In an outbreak in the Slave River lowlands and Wood Buffalo National Park, control was attempted with depopulation; 1,600 bison were killed (Broughton 1987). Transmission from bison to cattle has not been reported, but human infections from bison anthrax have been reported in several areas (Tessaro 1989). A bison-vaccination program was initiated in 1965 in Canada, but it was discontinued in 1978. Other Granulomatous Bacterial Diseases Yersiniosis Disseminated microabscesses surrounding colonies of Yersinia pseudotuberculosis occur sporadically in many species of wild mammals and birds. Wild rodents are reservoirs for this bacterium, and ingestion of grass contaminated with feces and predation by carnivores are sources of infection. Epizootics of yersiniosis have been reported in farmed cervids, including elk, fallow deer, red deer, and red-deer/elk hybrids (Sandford 1995). Yersiniosis is not an important disease in the GYA, and, although antigens of Yersinia spp. are

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known to cross-react with those of Brucella spp., there is no evidence that this is important in serology of bison and elk. Placentitis and abortion caused by Y. pseudotuberculosis occur in domestic sheep and goats, but transmission has not been associated with the reproductive tract. Serologic studies have shown that 86% of adult free-ranging YNP coyotes are seropositive for Y. pestis (Gese et al. 1997). Pasteurellosis Pasteurella multocida causes respiratory disease and septicemia in elk, and those diseases have been documented in YNP and in the NER (Franson and Smith 1988). The risk of transmission and mechanism of infection of Pasteurella spp. infections in bison and elk are not known. Granulomatous lesions resembling actinobacillosis lesions have been reported in lymph nodes of elk in the northern YNP region. Consisting of aggregates of macrophages with dense ''sulfur granules" composed of debris and bacteria, they can be confused with tuberculosis. A recent survey in YNP found an incidence of 15%. In some cases, Pasteurella hemolytica has been isolated from affected tissues. These lesions appear to be transmitted by contamination of wounds with the bacterium and might also be caused by different species of bacteria (J. Rhyan, APHIS, pers. commun., 1997). Vulgovaginitis Chronic inflammatory pyogranulomatous mucocutaneous lesions of the vulva are common in elk. The lesions can be large, ulcerating, and persistent. It is thought to be caused by an organism that resembles Corynebacterium renale. The pathogenesis has not been established. Whether vulgovaginitis interferes with reproduction has not been reported. Parasitic Diseases Lungworms Lungworms, Dictyocaulus spp., are common in elk in YNP; their incidence increases in the spring. The parasites are identified as D. viviparus elk strain

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or D. hadweni. In the 1960s, dissections of lungs of 59 YNP elk revealed lungworms in five animals. A study in Teton County, Wyoming, found incidences of 8%, 19%, and 15% in elk. Lungworms in land mammals are not associated with brucellosis, but in the new emerging forms of brucellosis in marine mammals, lungworms have been shown to carry Brucella spp. (Garner et al. 1997). Ostertagiasis Ostertagia ostertagi, a parasite of cattle, also infects bison. Bison-to-cattle spread has not been studied, although it has been stated that the capacity of bison parasites to infect cattle is of concern (Marley et al. 1995). Scabies Scabies is a highly contagious, enzootic infestation of wild ruminants and has been a problem for GYA elk. Rates of transmission are probably high, but scabies is a self-limited disease and does not typically cause debility or death. Psoroptes spp. burrows into the superficial layers of the skin to cause extensive chronic inflammation. Viral Diseases Few viral diseases are viewed as major causes of morbidity and mortality in bison and elk of the GYA, and data on risk of transmission are inadequate. Systemic viral infections similar to infectious bovine rhinotracheitis and bovine viral diarrhea exist, or could exist, in bison or elk. Serologic evidence of infection with bluetongue, epidemic hemorrhagic disease, infectious bovine rhinotracheitis, and bovine viral diarrhea can be found in elk and are most likely a reflection of their contact with cattle. Bluetongue and epidemic hemorrhagic disease can be lethal in deer species. Chronic wasting disease (CWD) of elk and deer is an infectious nervous system affliction that resembles scrapie in sheep in its clinical signs, distribution of lesions in brain, and presence of scrapie-associated prion protein in affected tissue (Spraker et al. 1997). Surveys of hunter-killed animals within a 100-mile radius of Fort Collins, Colorado, and Laramie, Wyoming, have

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shown a 6% incidence in mule deer and 1% incidence in elk (T. Spraker, pers. commun., 1997). Evidence of the etiologic agents is found in brain, spinal cord, and lymph nodes (by using a monoclonal antibody derived from antigens of ovine scrapie). CWD is considered one of the transmissible spongi-form encephalopathies that are potentially transmissible to other species, including humans. The disease has not been reported in elk or deer in the GYA, and no studies have been done on the danger that this disease has for humans.