在加拿大努纳武特地区，对作为食物而捕获的陆地和海洋野生动物进行弓形虫的血清学和分子检测。
Serological and molecular detection of Toxoplasma gondii in terrestrial and marine wildlife harvested for food in Nunavik, Canada.
机构信息
Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, S7H 5B4, Canada.
Groupe de Recherche en épidémiologie des Zoonoses et Santé Publique, Département de Pathologie et Microbiologie, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, J2S 2M2, Canada.
出版信息
Parasit Vectors. 2019 Apr 3;12(1):155. doi: 10.1186/s13071-019-3408-9.
BACKGROUND
Toxoplasma gondii, a zoonotic protozoan parasite, infects mammals and birds worldwide. Infection in humans is often asymptomatic, though illnesses can occur in immunocompromised hosts and the fetuses of susceptible women infected during pregnancy. In Nunavik, Canada, 60% of the Inuit population has measurable antibodies against T. gondii. Handling and consumption of wildlife have been identified as risk factors for exposure. Serological evidence of exposure has been reported for wildlife in Nunavik; however, T. gondii has not been detected in wildlife tissues commonly consumed by Inuit.
METHODS
We used a magnetic capture DNA extraction and real-time PCR protocol to extract and amplify T. gondii DNA from large quantities of tissues (up to 100 g) of 441 individual animals in Nunavik: 166 ptarmigan (Lagopus lagopus), 156 geese (Branta canadensis and Chen caerulescens), 61 ringed seals (Pusa hispida), 31 caribou (Rangifer tarandus) and 27 walruses (Odobenus rosmarus).
RESULTS
DNA from T. gondii was detected in 9% (95% CI: 3-15%) of geese from four communities in western and southern Nunavik, but DNA was not detected in other wildlife species including 20% (95% CI: 12-31%) of ringed seals and 26% (95% CI: 14-43%) of caribou positive on a commercial modified agglutination test (MAT) using thawed heart muscle juice. In geese, tissue parasite burden was highest in heart, followed by brain, breast muscle, liver and gizzard. Serological results did not correlate well with tissue infection status for any wildlife species.
CONCLUSIONS
To our knowledge, this is the first report on the detection, quantification, and characterization of DNA of T. gondii (clonal lineage II in one goose) from wildlife harvested for food in Nunavik, which supports the hypothesis that migratory geese can carry T. gondii into Nunavik where feline definitive hosts are rare. This study suggests that direct detection methods may be useful for detection of T. gondii in wildlife harvested for human consumption and provides data needed for a quantitative exposure assessment that will determine the risk of T. gondii exposure for Inuit who harvest and consume geese in Nunavik.
背景
刚地弓形虫是一种人畜共患的原生动物寄生虫，在全球范围内感染哺乳动物和鸟类。人类感染通常无症状，但在免疫功能低下的宿主和怀孕期间感染易感妇女的胎儿中，可能会出现疾病。在加拿大努纳武特地区，60%的因纽特人口有可测量的抗刚地弓形虫抗体。处理和食用野生动物已被确定为暴露的危险因素。在努纳武特地区的野生动物中已报告了血清学暴露证据；然而，在因纽特人常食用的野生动物组织中尚未检测到刚地弓形虫。
方法
我们使用一种磁性捕获 DNA 提取和实时 PCR 方案，从努纳武特地区 441 只个体动物的大量组织（高达 100 克）中提取和扩增刚地弓形虫 DNA：166 只松鸡（Lagopus lagopus）、156 只鹅（Branta canadensis 和 Chen caerulescens）、61 只环斑海豹（Pusa hispida）、31 只驯鹿（Rangifer tarandus）和 27 只海象（Odobenus rosmarus）。
结果
在来自努纳武特西部和南部四个社区的 9%（95%置信区间：3-15%）的鹅中检测到刚地弓形虫 DNA，但在其他野生动物物种中未检测到 DNA，包括 20%（95%置信区间：12-31%）的环斑海豹和 26%（95%置信区间：14-43%）的驯鹿，它们在使用解冻心肌汁的商业改良凝集试验（MAT）上呈阳性。在鹅中，心脏组织中的寄生虫负荷最高，其次是大脑、胸肌、肝脏和肌胃。血清学结果与任何野生动物物种的组织感染状况相关性都不佳。
结论
据我们所知，这是首次报告从努纳武特地区收获的食用野生动物中检测、定量和表征刚地弓形虫 DNA（一只鹅中的克隆谱系 II），这支持了迁徙鹅可以将刚地弓形虫带入努纳武特地区，而那里的猫科终宿主很少的假设。本研究表明，直接检测方法可能有助于检测食用野生动物中的刚地弓形虫，并提供定量暴露评估所需的数据，以确定在努纳武特地区收获和食用鹅的因纽特人感染刚地弓形虫的风险。
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