Submitted to: Veterinary Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/20/2010
Publication Date: 1/10/2011
Citation: Sepulveda, M.A., Munoz-Zanzi, C., Rosenfeld, C., Jara, R., Pelican, K.M., Hill, D.E. 2011. Toxoplasma gondii in feral american minks at the Maullin river, Chile. Veterinary Parasitology. 175(1-2):60-65. Interpretive Summary: American mink (Neovison vison), a mustelid carnivore species, was first brought to Chile in the 1930’s for the pelt industry. In the 1970’s feral populations of mink farm escapees were first reported. At present, the species is considered an invasive species and is widely distributed throughout Southern Chile including Tierra del Fuego Island (38º 35’S to 55º S) and adjacent archipelagos. Research on the American mink in this neotropical area has focused mainly on diet, distribution, and aspects of interspecific competition and predation. Monitoring of specific pathogens in free-ranging carnivores can provide estimates of environmental contamination because of the high risk of exposure associated with their trophic position. However, there are no published studies on the infections present in feral mink populations in South America. The objective of this study was to describe T. gondii infection in American mink in Chile and to identify factors associated with infection, most importantly, proximity to human populations. Secondary objectives included description of dietary aspects and abundances. This information will be of interest to animal parasitologists, veterinarians, and epidemiologists who study the impact of human settlement on sylvatic species.
Technical Abstract: American mink (Neovison vison) is a widely distributed invasive species in southern Chile. Thirty four feral minks were trapped at two distinct sites (rural and peri-urban), diet analyzed, and Toxoplasma gondii exposure compared using PCR and specific antibodies. Serum samples were evaluated using a commercial latex agglutination test where a titer =1:32 was considered positive. Of 30 mink analyzed, 21 (70%) were positive to T. gondii antibodies, with titers ranging from 1:32 to 1:2,048. As expected, adult mink showed higher seroprevalence of exposure to T. gondii (18/21) than young mink (3/9) (P = 0.008). There was no statistically significant difference between sexs (P =0.687). Differences in seroprevalence were observed between the two sample sites with a higher proportion of positive individuals in the peri-urban area, and therefore, closer to human settlements (35.7% vs. 100%, P = 0.0001). Individuals positive to T. gondii using PCR and/or serology showed similar differences by site with higher numbers of infected individuals in peri-urban areas (58.8% vs. 100%, P = 0.007). Diet of American mink was mainly based on crustaceans (frequency of occurrence in feces: crustaceans =100%, birds and rodents < 7%), suggesting that the high observed prevalence of T. gondii infection may be associated with its aquatic behavior (e.g. ingestion of oocysts in contaminated fresh water) than with their trophic behavior (e.g. preying on species with T. gondii tissue cysts). Minks may be useful as a sentinel species to monitor pathogens of public and wildlife health importance, such as T. gondii, in aquatic environments.