Hill N J, Dubey J P, Vogelnest L, Power M L, Deane E M
Department of Biological Sciences, Division of Environmental & Life Sciences, Macquarie University, Epping Road, North Ryde, NSW 2109, Australia.
Vet Parasitol. 2008 Apr 15;152(3-4):202-9. doi: 10.1016/j.vetpar.2008.01.002. Epub 2008 Jan 8.
To investigate the possible role of common brushtail possums (Trichosurus vulpecula) in the transmission of Toxoplasma gondii within a zoo environment, a serological survey of a free-ranging population resident within Taronga Zoo, Sydney, Australia was undertaken using the modified agglutination test (MAT). For comparison, the seroprevalence of T. gondii antibodies was also assessed in a possum population inhabiting a felid-free, non-urban woodland habitat. Six of 126 possums (4.8%) from the zoo population had antibodies to T. gondii with a MAT titre of 25 or higher, while in contrast, all of the 17 possums from woodland were seronegative. These observations suggest that possums were at a higher risk of exposure to the parasite as a consequence of co-existing with domestic, stray and captive felids associated with urbanisation. Screening of captive felids at the zoo indicated 16 of 23 individuals (67%) and all 6 species were seropositive for T. gondii, implicating them as a possible source of the parasite within the zoo setting. In addition captive, non-felid carnivores including the chimpanzee (Pan troglodytes), saltwater crocodile (Crocodylus porosus), dingo (Canis lupis) and leopard seal (Hydrurga leptonyx) were tested for the presence of T. gondii antibodies as these species predate and are a leading cause of death amongst zoo possums. In total, 5 of 23 individuals (22%) were seropositive, representing 2 of the 4 carnivorous species; the dingo and chimpanzee. These data suggest that carnivory was not a highly efficient pathway for the transmission of T. gondii and the free-ranging possum population posed minimal threat to the health of zoo animals.
为了研究帚尾袋貂（Trichosurus vulpecula）在动物园环境中传播刚地弓形虫（Toxoplasma gondii）的潜在作用，我们采用改良凝集试验（MAT）对澳大利亚悉尼塔龙加动物园内自由放养的袋貂种群进行了血清学调查。作为对比，我们还评估了生活在无猫科动物、非城市林地栖息地的袋貂种群中弓形虫抗体的血清阳性率。动物园种群的126只袋貂中有6只（4.8%）对弓形虫有抗体，MAT滴度为25或更高，而相比之下，来自林地的17只袋貂全部血清学阴性。这些观察结果表明，由于与城市化相关的家养、流浪和圈养猫科动物共存，袋貂接触该寄生虫的风险更高。对动物园内圈养猫科动物的筛查显示，23只个体中有16只（67%）以及所有6个物种对弓形虫血清学阳性，这表明它们可能是动物园环境中该寄生虫的一个来源。此外，对包括黑猩猩（Pan troglodytes）、咸水鳄（Crocodylus porosus）、澳洲野犬（Canis lupis）和豹海豹（Hydrurga leptonyx）在内的圈养非猫科食肉动物进行了弓形虫抗体检测，因为这些物种会捕食袋貂，且是动物园袋貂死亡的主要原因。总共23只个体中有5只（22%）血清学阳性，代表了4个食肉物种中的2个；澳洲野犬和黑猩猩。这些数据表明，食肉并非弓形虫传播的高效途径，自由放养的袋貂种群对动物园动物健康构成的威胁极小。
