Epizootiologic investigations of selected infectious disease agents in free-ranging Eurasian lynx from Sweden

Serum samples from 106 Eurasian lynx (Lynx lynx) from across Sweden, found dead or shot by hunters in 1993-99, were investigated for presence of antibodies to feline parvovirus (FPV), feline coronavirus, feline calicivirus, feline herpesvirus, feline immunodeficiency virus, Francisella tularensis, and Anaplasma phagocytophila, and for feline leukemia virus antigen. In addition, tissue samples from 22 lynx submitted in 1999 were analyzed by real-time polymerase chain reaction (PCR) to detect nucleic acids specific for viral agents and A. phagocytophila. Except for FPV antibodies in one lynx and A. phagocytophila in four lynx, all serology was negative. All PCR results also were negative. It was concluded that free-ranging Swedish lynx do not have frequent contact with the infectious agents considered in this study.     

Bovine tuberculosis in free-ranging carnivores from Michigan

During a survey of carnivores and omnivores for bovine tuberculosis conducted in Michigan (USA) since 1996, Mycobacterium bovis was cultured from lymph nodes pooled from six coyotes (Canis latrans) (four adult female, two adult male), two adult male raccoons (Procyon lotor), one adult male red fox (Vulpes vulpes), and one 1.5-yr-old male black bear (Ursus americanus). One adult, male bobcat (Felis rufus) with histologic lesions suggestive of tuberculosis was negative on culture but positive for organisms belonging to the Mycobacterium tuberculosis complex when tested by polymerase chain reaction. All the tuberculous animals were taken from three adjoining counties where M. bovis is known to be endemic in the free-ranging white-tailed deer (Odocoileus virginianus) population. There were two coyotes, one raccoon, one red fox, and one bobcat infected in Alpena county. Montmorency County had two coyotes and one raccoon with M. bovis. Two coyotes and a bear were infected from Alcona County. These free-ranging carnivores/omnivores probably became infected with M. bovis through consumption of tuberculous deer. Other species included in the survey were opossum (Didelphis virginiana), gray fox (Urocyon cinereoargenteus), and badger (Taxidea taxus); these were negative for M. bovis.     

Epizootiologic investigations of selected abortive agents in free-ranging Alpine ibex (Capra ibex ibex) in Switzerland

In the early 2000s, several colonies of Alpine ibex (Capra ibex ibex) in Switzerland ceased growing or began to decrease. Reproductive problems due to infections with abortive agents might have negatively affected recruitment. We assessed the presence of selected agents of abortion in Alpine ibex by serologic, molecular, and culture techniques and evaluated whether infection with these agents might have affected population densities. Blood and fecal samples were collected from 651 ibex in 14 colonies throughout the Swiss Alps between 2006 and 2008. All samples were negative for Salmonella spp., Neospora caninum, and Bovine Herpesvirus-1. Antibodies to Coxiella burnetii, Leptospira spp., Chlamydophila abortus, Toxoplasma gondii, and Bovine Viral Diarrhea virus were detected in at least one ibex. Positive serologic results for Brucella spp. likely were false. Overall, 73 samples (11.2%) were antibody-positive for at least one abortive agent. Prevalence was highest for Leptospira spp. (7.9%, 95% CI=5.0-11.7). The low prevalences and the absence of significant differences between colonies with opposite population trends suggest these pathogens do not play a significant role in the population dynamics of Swiss ibex. Alpine ibex do not seem to be a reservoir for these abortive agents or an important source of infection for domestic livestock in Switzerland. Finally, although interactions on summer pastures occur frequently, spillover from infected livestock to free-ranging ibex apparently is uncommon.     

Epizootiologic and ecologic investigations of European brown hares (Lepus europaeus) in selected populations from Schleswig-Holstein, Germany

From 1997-99 European brown hare (Lepus europaeus) population densities were estimated by spotlight surveys within different areas in Schleswig-Holstein, Germany. These areas showed a wide variation in local hare population densities. In addition, red fox (Vulpes vulpes) densities were estimated in 1997 by surveys of fox dens and litters. Sera of 321 hares (shot between 1998-2000) from four study areas were examined for antibodies against European brown hare syndrome virus (EBHSV) by enzyme linked immunosorbent assay (ELISA), Yersinia spp. (n = 299) and Francisella tularensis (n = 299) by western blotting, Brucella spp. by Rose Bengal test, and Toxoplasma gondii by Sabin-Feldman test (n = 318). Tissue samples comprising lung, liver, spleen, kidney, heart, and adrenal glands were collected for histopathology. Liver (n = 201) and spleen (n = 201) samples were processed for the detection of T. gondii-antigen in tissue sections and 321 liver and spleen samples were investigated for EBHSV-antigen by ELISA. Furthermore, 116 hares were examined macro- and microscopically for lungworms. Significant negative correlations between hare and fox densities were found in spring and autumn 1997. Antibodies against EBHSV were detected in 92 of 321 (29%), against Yersinia spp. in 163 of 299 (55%), and against T. gondii in 147 of 318 (46%) hares. We evaluated the potential influence of origin and hunting season on exposure rates of hares using logistic regression analysis. A strong association between hare densities and exposure rates was observed for various agents. One hundred and eight of 201 (57%) hares were positive for T. gondii-antigen. All sera were negative for antibodies against Brucella spp. and F. tularensis and all lung samples were negative for lungworms. In conclusion, variation in red fox densities may have an impact on the hare populations examined and the infectious diseases we studied seem to play a subordinate role in the dynamics of European brown hare populations from Schleswig-Holstein.     

Antibodies to Aleutian mink disease parvovirus in free-ranging European mink (Mustela lutreola) and other small carnivores from southwestern France

Owing to the rapid decline of the European mink (Mustela lutreola) in France, a national conservation action plan has been initiated, in which scientific research to improve understanding of the causes of the decline is one of the primary objectives. In order to investigate the possible role of Aleutian disease parvovirus (ADV) in decline of the species, a serologic survey was conducted from March 1996 to March 2002 in 420 free-ranging individuals of six species of small carnivores distributed in eight departments of southwestern France. Antibodies to ADV were detected in 17 of 75 American mink (Mustela vison), 12 of 99 European mink, 16 of 145 polecats (Mustela putorius), four of 17 stone martens (Martes foina), one of 16 pine martens (Martes martes), and three of 68 common genets (Genetta genetta). Seroprevalence was significantly higher in American mink than in other species. Seropositive individuals with gamma globulin levels >20% were observed in four European mink, four American mink, two stone martens, and one pine marten. Geographic distribution of positive animals indicates the virus has spread to all areas where European mink are found. Furthermore, a trend of increasing prevalence seems to appear in Mustela sp. sympatric with American mink. Although further investigations are necessary to evaluate the role of ADV in decline of European mink, evidence of the virus in the wild at the levels found in our study has implications for conservation of this species.     

Detection of rabies virus antibodies in Brazilian free-ranging wild carnivores

Rabies virus is a pathogen of major concern in free-ranging wild carnivores in several regions of the world, but little is known about its circulation in Brazilian wild carnivores. Sera from 211 free-ranging wild carnivores, captured from 2000 to 2006 in four locations of two Brazilian biomes (Pantanal and Cerrado), were tested for rabies antibodies. Twenty-six individuals (12.3%) had neutralizing antibody titers ≥0.10 IU/ml. The four sampled locations had antibody-positive animals, suggesting that Rabies virus circulates in all of these regions. Results underscore the risk posed by rabies for conservation of Brazilian carnivores and the possibility of the animals acting as reservoirs for the Rabies virus.     

Aleutian mink disease parvovirus in wild riparian carnivores in Spain

Serious declines in populations of native European mink (Mustela lutreola) have occurred in Europe. One responsible factor may be infectious diseases introduced by exotic American mink (Mustela vison). In order to investigate a possible role for Aleutian mink disease parvovirus (ADV), we surveyed native riparian carnivores and feral American mink. When serum samples from 12 free-ranging European and 16 feral American mink were tested, antibodies to ADV were detected from three of nine European mink. ADV DNA was detected by polymerase chain reaction in whole cell DNA from four of seven carcasses; two American mink, one European mink and a Eurasian otter (Lutra lutra). Lesions typical of Aleutian disease were present in one of the American mink. A portion of the ADV VP2 capsid gene was sequenced and the results suggested that two sequence types of ADV were circulating in Spain, and that the Spanish ADVs differed from other described isolates from North America and Europe. Future conservation and restoration efforts should include measures to avoid introduction or spread of ADV infection to native animals.     

Occurrence of mycoplasmas in free-ranging birds of prey in Germany

Mycoplasmas are well-known avian pathogens of poultry and some passerines. Although reported in birds of prey, their role as pathogens is still unclear. Healthy, free-ranging raptor nestlings sampled during a routine ringing (banding) program, and birds of prey from rehabilitation centers, tested positive for Mycoplasma spp. by culture and a genus-specific polymerase chain reaction (PCR). Given the lack of clinical signs and disease, we suggest that mycoplasmas in raptors may be commensal rather than pathogenic. Using immunobinding assay and species-specific PCR tests, Mycoplasma buteonis, M. falconis, and M. gypis were identified; M. falconis was only detected in falcons. Additionally, some isolates could not be identified. This is the first report of Mycoplasma spp. isolations from Western Marsh Harriers (Circus aeroginosus), a Eurasian Hobby (Falco subbuteo), and a Barn Owl (Tyto alba).     

Use of real-time PCR to detect canine parvovirus in feces of free-ranging wolves

Using real-time PCR, we tested 15 wolf (Canis lupus) feces from the Superior National Forest (SNF), Minnesota, USA, and 191 from Yellowstone National Park (YNP), USA, collected during summer and 13 during winter for canine parvovirus (CPV)-2 DNA. We also tested 20 dog feces for CPV-2 DNA. The PCR assay was 100% sensitive and specific with a minimum detection threshold of 10(4) 50% tissue culture infective dose. Virus was detected in two winter specimens but none of the summer specimens. We suggest applying the technique more broadly especially with winter feces.     

Serological survey for potential disease agents of free-ranging cervids in six selected national parks from Germany

A total of 164 blood samples, collected from free-ranging red deer (Cervus elaphus), roe deer (Capreolus capreolus) and fallow deer (Dama dama) in six German national parks (NP) between 2000 and 2002, were assayed for antibodies against nine viral disease agents. Antibodies were only detected against the alpha-herpesviruses; specifically, bovine herpesvirus-1 (BHV-1) (22 of 157, 14%), cervid herpesvirus-1 (17 of 157, 10.8%), and caprine herpesvirus-1 (11 of 159, 6.9%). Titers ranged from 4 to 102. Most of the seropositive sera, and those with the highest antibody titers, were from red and roe deer in the Harz and Hochharz NP, which are connected and allow migration between the two. The distribution and specificity of antibodies detected in individual deer suggests that the three alpha-herpesviruses are circulating in these deer populations. No antibodies were detected against bovine viral diarrhea virus, epizootic hemorrhagic disease virus, bovine leukemia virus, bluetongue virus, foot-and-mouth disease virus, or sheep and goat poxvirus.     

Demographic effects of canine parvovirus on a free-ranging wolf population over 30 years

We followed the course of canine parvovirus (CPV) antibody prevalence in a subpopulation of wolves (Canis lupus) in northeastern Minnesota from 1973, when antibodies were first detected, through 2004. Annual early pup survival was reduced by 70%, and wolf population change was related to CPV antibody prevalence. In the greater Minnesota population of 3,000 wolves, pup survival was reduced by 40-60%. This reduction limited the Minnesota wolf population rate of increase to about 4% per year compared with increases of 16-58% in other populations. Because it is young wolves that disperse, reduced pup survival may have caused reduced dispersal and reduced recolonization of new range in Minnesota.     

Leptospirosis in free-ranging endangered European mink (Mustela lutreola) and other small carnivores (Mustelidae, Viverridae) from southwestern France

To study the possible role of disease in the decline of endangered European mink (Mustela lutreola), we conducted a survey of antibody prevalence and renal carriage of pathogenic leptospira (Leptospira interrogans sensu lato) using serum and kidney samples collected from 1990 to 2007 from several free-ranging small carnivores and farmed American mink (Mustela vison) in southwestern France. An indirect microscopic agglutination test using a panel of 16 serovars belonging to 6 serogroups (Australis, Autumnalis, Icteroh?morrhagi?, Grippotyphosa, Panama, Sejroe) revealed antibodies in all species, with significant differences in antibody prevalences: 74% in European mink (n=99), 65.4% in European polecats (Mustela putorius, n=133), 86% in American mink (n=74), 89% in stone martens (Martes foina, n=19), 74% in pine martens (Martes martes, n=19), 35% in common genets (Genetta genetta, n=79), and 31% in farmed American mink (n=51). Serogroups Australis and Icteroh?morragi? were dominant in most free-ranging species; serogroup Grippotyphosa had high prevalences in European mink. Such high antibody prevalences have never been reported. They are probably related to the large number of known reservoirs, rats (Rattus spp.), muskrat (Ondatra zibethicus), and coypu (Myocastor coypu), in the study area. The polymerase chain reaction test specific for pathogenic leptospiral DNA detected renal carriage in 23% of 34 European mink, 22% of 18 polecats, and 15% of 33 free-ranging American mink, with no significant differences. Renal carriage shows that mustelids may shed leptospira for short periods, but their epidemiologic role is probably limited. High antibody prevalences suggest that the disease is unlikely to be highly pathogenic for these species; however, chronic forms of the disease (abortions, renal lesions) could reduce the reproductive success or life span of infected animals. Further studies on the pathogenicity of leptospirosis in these populations are needed to measure its impact on the population dynamics of these rodent predators.     

Exposure of free-ranging wild carnivores, horses and domestic dogs to Leptospira spp in the northern Pantanal, Brazil

Leptospirosis is a zoonotic disease affecting most mammals and is distributed throughout the world. Several species of domestic and wild animals may act as reservoirs for this disease. The purpose of this study was to assess the exposure of free-ranging wild carnivores, horses and domestic dogs on a private reserve located in the northern Pantanal (Brazil) and the surrounding areas to Leptospira spp from 2002-2006, 75 free-ranging wild carnivores were captured in the Pantanal and serum samples were collected. In addition, samples from 103 domestic dogs and 23 horses in the region were collected. Serum samples were tested for the presence of Leptospira antibodies using the microscopic agglutination test. Thirty-two wild carnivores (42.7%) were considered positive with titres ≥ 100, and 18 domestic dogs (17.5%) and 20 horses (74.1%) were also found to be positive. Our study showed that horses, dogs and several species of free-ranging wild carnivores have been exposed to Leptospira spp in the Pantanal, suggesting that the peculiar characteristics of this biome, such as high temperatures and an extended period of flooding, may favour bacterial persistence and transmission. In this region, wild carnivores and horses seem to be important hosts for the epidemiology of Leptospira species.     

Serosurvey for selected virus infections of wild carnivores in Taiwan and Vietnam.

Serum samples from two leopard cats (Felis bengalensis) and four Formosan gem-faced civets (Paguma larvata taivana) in Taiwan, September 1995, and nine leopard cats in Vietnam, August and December 1997, were examined for the prevalence of antibodies against feline parvovirus, feline herpesvirus type 1, feline calicivirus and feline immunodeficiency virus. All civets and nine of 11 leopard cats were shown to have antibodies against feline parvovirus (FPV), and FPV's were isolated from mononuclear cells in the peripheral blood of the six leopard cats.