Neospora Caninum and Toxoplasma Gondii Antibody Prevalence in Alaska Wildlife

Abstract

ABSTRACT:Free-ranging caribou and moose populations in some regions of Alaska undergo periodic declines in numbers. Caribou and moose are managed by the state as valuable resources for not only sustenance and subsistence, but also for cultural heritage. Incidence and prevalence of diseases that may impact herd health and recruitment from year to year are relevant to management decisions aimed to protect the long-term viability of these herds. Neospora caninum and Toxoplasma gondii are two apicomplexan parasites that can cause neurologic disease and abortions in their intermediate hosts and less frequently cause disease in their definitive hosts. The definitive hosts of N. caninum and T. gondii are canids and felids, respectively, and prevalence in the environment is in part dependent on maintenance of the life cycle through the definitive hosts. Serum samples from caribou (Rangifer tarandus, n5453), wolf (Canis lupus, n5324), moose (Alces alces, n5201), black-tailed deer (Odocoileus hemionus, n555), coyote (Canis latrans, n512), and fox (Vulpes vulpes, n59) collected in Alaska were assayed for N. caninum-and T. gondii-reactive antibodies with an immunofluorescent antibody test (IFAT) and a modified agglutination test (MAT), respectively. Seroprevalence of N. caninum was greater in caribou (11.5%) than in wolves (9.0%), moose (0.5%), or black-tailed deer (0%). Seroprevalence of T. gondii was greater in wolves (17.8%) than in caribou (0.4%), moose (0%), or black-tailed deer (0%). Seroprevalence of N. caninum and T. gondii were 16.7% and 0.0% in coyotes and 0.0% and 12.5% in fox, but small sample sizes prevented further analysis. Antibodies to N. caninum in young caribou compared to adult caribou suggest that vertical transmission may be an important component of new infections in Alaskan caribou. The spatial distribution of antibody-positive individuals across Alaska may reflect differences in frequency of definitive hosts and alteration of predation patterns among regions.

Toxoplasmosis in Natural Populations of Ungulates in France: Prevalence and Spatiotemporal Variations

“…In geographic areas within the Arctic Circle (north of 66°33¢39), prevalences range from 0.4% to 8.6% in moose (Alces alces), black-tailed deer (Odocoileus hemionus), dall sheep (Ovis dalli), caribou (Rangifer tarandus), and bison (Bison bison) (Zarnke et al 2000, Jokelainen et al 2010, Stieve et al 2010, Malmsten et al 2011. Low prevalences in northern territories have been attributed to the low density of domestic cats where human population is very scarce.…”

The Life Cycle of Toxoplasma gondii in the Natural Environment

“…In Chile, the prevalence in American minks Neovison vison was highest at proximity of human settlements [116]. Finally, when wild-living cats are present, they constitute a strong determinant of T. gondii in wildlife: at the national level, T. gondii prevalence in French wild boar is high in the area of presence of the European wildcat Felis silvestris [90]; in Alaska, the prevalence of infection in herbivorous species reflects the distribution of lynx Felis canadensis in the area [117]. Here it is important to underline that, in order to find relevant explanatory spatial factors, these have to be measured at the appropriate scale.…”

Genetic characterisation of Toxoplasma gondii in wildlife from North America revealed widespread and high prevalence of the fourth clonal type

“…Antibodies to T. gondii were reported previously in 9% of 125 (Zarnke et al, 2000) and 17.8% of 320 (Stieve et al, 2010) wolves from Alaska. Five of these wolf T. gondii strains were successfully genotyped, with four belonging to Type 12 and one to genotype #9 (Table 2).…”