Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Isla Teja s/n, Casilla 567, Valdivia, Chile.
Vet Parasitol. 2011 Jan 10;175(1-2):60-5. doi: 10.1016/j.vetpar.2010.09.020. Epub 2010 Sep 29.
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 1:2048. As expected, adult mink showed higher seroprevalence of exposure to T. gondii (18/21) than young mink (3/9) (P=0.008). There was not statistically significant difference between sex groups (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 infected individuals in peri-urban areas (58.8% vs. 100%, P=0.007). Diet of American mink based in fecal composition analyses was mainly based on crustaceans (frequency of occurrence: crustaceans=100%, birds and rodents<7%), suggesting that the high observed prevalence of T. gondii infection might be more associated with its aquatic behavior (e.g. ingestion of oocysts in contaminated fresh water) than with their trophic behavior (e.g. preying over species that can have T. gondii cysts in their tissues). As an invasive species potentially subject to routine culling to maintain population sizes under control, minks could be used as a sentinel species to monitor pathogens of public and wildlife health importance, such as T. gondii, in aquatic environments.
美洲水貂（Neovison vison）是智利南部广泛分布的入侵物种。在两个不同地点（农村和城郊）诱捕了 34 只野化水貂，分析了它们的饮食，并通过 PCR 和特定抗体比较了弓形虫的暴露情况。使用商业乳胶凝集试验评估血清样本，将滴度≥1:32 视为阳性。在分析的 30 只水貂中，有 21 只（70%）对弓形虫抗体呈阳性，滴度范围为 1:32 至 1:2048。正如预期的那样，成年水貂对弓形虫的暴露血清阳性率（18/21）高于幼貂（3/9）（P=0.008）。性别组之间没有统计学上的显著差异（P=0.687）。在两个采样点之间观察到血清阳性率存在差异，靠近人类住区的城郊地区阳性个体比例更高（35.7%对 100%，P=0.0001）。通过 PCR 和/或血清学检测为阳性的个体在采样点之间也存在类似的差异，城郊地区感染个体比例更高（58.8%对 100%，P=0.007）。根据粪便成分分析，美洲水貂的饮食主要以甲壳类动物为主（出现频率：甲壳类动物=100%，鸟类和啮齿动物<7%），这表明观察到的弓形虫高感染率可能与其水生行为（例如摄入受污染淡水中的卵囊）更为相关，而与其营养行为（例如捕食组织中有弓形虫包囊的物种）关系不大。作为一种可能受到常规捕杀以控制种群数量的入侵物种，水貂可以作为监测水生环境中对公共和野生动物健康具有重要意义的病原体（如弓形虫）的哨兵物种。
