Bouchard Émilie, Elmore Stacey A, Alisauskas Ray T, Samelius Gustaf, Gajadhar Alvin A, Schmidt Keaton, Ross Sasha, Jenkins Emily J
1 Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada.
2 Department of Fish, Wildlife, and Conservation Biology, Colorado State University, US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, 4101 Laporte Avenue, Fort Collins, Colorado 80521, USA.
J Wildl Dis. 2019 Jul;55(3):619-626. doi: 10.7589/2018-06-144. Epub 2018 Nov 28.
Transmission dynamics of , a parasite of importance for wildlife and human health, are enigmatic in the Arctic tundra, where free-ranging wild and domestic felid definitive hosts are absent and rarely observed, respectively. Through a multiyear mark-recapture study (2011-17), serosurveillance was conducted to investigate transmission of in Arctic foxes () in the Karrak Lake region, Nunavut, Canada. Sera from adult foxes and fox pups were tested for antibodies to by using serologic methods, including the indirect fluorescent antibody test, direct agglutination test, and modified agglutination test. The overall seroprevalence was 39% in adults and 17% in pups. Mature foxes were more likely to be exposed (seroconvert) than young foxes (less than 1 yr old), with the highest level of seroprevalence in midaged foxes (2-4 yr old). Pups in two different litters were seropositive on emergence from the den, around 5 wk old, which could have been due to passive transfer of maternal antibody or vertical transmission of from mother to offspring. The seropositive pups were born of seropositive mothers that were also seropositive the year before they gave birth, suggesting that vertical transmission might not be limited to litters from mothers exposed to for the first time in pregnancy. All recaptured seropositive foxes remained seropositive on subsequent captures, suggesting that antibodies persist or foxes are constantly reexposed or a combination of both. The results of this study provided insights into how foxes were likely exposed to , the dynamics of antibody persistence and immune response, and how the parasite was maintained in a terrestrial Arctic ecosystem in the absence of felid definitive hosts.
对于野生动物和人类健康都很重要的一种寄生虫，其传播动态在北极苔原地区仍是个谜，在那里，自由放养的野生和家养猫科动物终宿主分别不存在且很少被观察到。通过一项为期多年的标记重捕研究（2011 - 2017年），在加拿大努纳武特地区的卡拉克湖地区对北极狐（）进行了血清学监测，以调查该寄生虫的传播情况。使用包括间接荧光抗体试验、直接凝集试验和改良凝集试验在内的血清学方法，检测成年狐狸和幼狐血清中针对该寄生虫的抗体。成年狐狸的总体血清阳性率为39%，幼狐为17%。成年狐狸比幼狐（小于1岁）更有可能接触（血清转化）该寄生虫，中年狐狸（2 - 4岁）的血清阳性率最高。两窝不同的幼狐在约5周大从巢穴出来时血清呈阳性，这可能是由于母源抗体的被动转移或该寄生虫从母亲到后代的垂直传播。血清阳性的幼狐出生于血清阳性的母亲，这些母亲在分娩前一年也是血清阳性，这表明垂直传播可能不限于首次在怀孕期间接触该寄生虫的母亲所生的幼崽。所有重新捕获的血清阳性狐狸在后续捕获时仍为血清阳性，这表明抗体持续存在，或者狐狸不断再次接触该寄生虫，或者两者兼而有之。这项研究的结果为狐狸如何可能接触该寄生虫、抗体持久性和免疫反应的动态以及在没有猫科动物终宿主的情况下该寄生虫如何在北极陆地生态系统中维持提供了见解。
