A partition of Toxoplasma gondii genotypes across spatial gradients and among host species, and decreased parasite diversity towards areas of human settlement in North America
A partition of Toxoplasma gondii genotypes across spatial gradients and among host species, and decreased parasite diversity towards areas of human settlement in North America
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DOI：
10.1016/j.ijpara.2018.01.008
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发表时间：
2018-07-01
影响因子：
4
通讯作者：
Su, Chunlei
中科院分区：
文献类型：
--
作者：
Jiang, Tiantian;Shwab, E. Keats;Su, Chunlei
弓形虫是最严重的食源性寄生虫之一，尽管这种寄生虫存在于广泛的野生和家养动物中，但农场可能构成一个特定和重要的传播场所。如果是这样的话，居住在农业栖息地的动物体内的寄生虫可能被怀疑携带着不同的基因类型的寄生虫。为了更好地了解与这种寄生虫传播相关的栖息地影响，我们收集并分析了现有的623个样本的基因分型数据，这些样本来自北美从人类聚居区到荒野的近距离梯度上的动物。为了便于这种分析，弓形虫分离株被分为三组：(I)来自农场动物(农场的栖息地范围最有限)；(Ii)来自自由漫游的动物(农场或附近有更广泛的栖息地)；以及(Iii)野生动物。此外，还对不同动物种的寄生虫基因分布进行了分析。我们没有观察到五种主要基因型中的任何一种对任何一个栖息地的绝对限制；然而，从农场限制组到自由漫游组，再到野生动物，四种基因型的频率在梯度上降低，而第五种基因型的频率沿着该梯度增加。自由漫游动物的遗传多样性比农场动物的遗传多样性更大。野生动物中寄生虫的基因组成与农场和自由漫游动物中的不同。此外，不同寄主物种的寄生虫基因型别也不同。我们得出结论：弓形虫的基因分布受空间栖息地和宿主物种组成的影响，寄生虫多样性向人类聚居区递减，阐明了可能影响这种无处不在但具有区域变异性的寄生虫的传播动力学和人畜共患病潜力的事实。(C)2018年澳大利亚寄生虫学学会。爱思唯尔有限公司出版。保留所有权利。
Toxoplasma gondii counts among the most consequential food-borne parasites, and although the parasite occurs in a wide range of wild and domesticated animals, farms may constitute a specific and important locus of transmission. If so, parasites in animals that inhabit agricultural habitats might be suspected of harbouring genetically distinct parasite types. To better understand habitat effects pertinent to this parasite's transmission, we compiled and analysed existing genotypic data of 623 samples from animals across a proximity gradient from areas of human settlement to the wilderness in North America. To facilitate such analysis, T. gondii isolates were divided into three groups: (i) from farm-bound animals (with the most limited home ranges on farms); (ii) from free-roaming animals (with wider home ranges on or near farms); and (iii) from wildlife. In addition, parasite genotype distribution in different animal species was analysed. We observed no absolute limitation of any of five major genotypes to any one habitat; however, the frequency of four genotypes decreased across the gradient from the farm-bound group, to the free-roaming group, then the wildlife, whereas a fifth genotype increased along that gradient. Genetic diversity was greater in free-roaming than in farm-bound animals. The genotypic composition of parasites in wildlife differed from those in farm-bound and free-roaming animals. Furthermore, parasite genotypes differed among host species. We conclude that T. gondii genotype distributions are influenced by the spatial habitat and host species composition, and parasite diversity decreases towards areas of human settlement, elucidating facts which may influence transmission dynamics and zoonotic potential in this ubiquitous but regionally variable parasite. (C) 2018 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.