Dubey J P, Graham D H, De Young R W, Dahl E, Eberhard M L, Nace E K, Won K, Bishop H, Punkosdy G, Sreekumar C, Vianna M C B, Shen S K, Kwok O C H, Sumners J A, Demarais S, Humphreys J G, Lehmann T
Animal Parasitic Diseases Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agriculture, Building 1001, Beltsville, Maryland 20705-2350, USA.
J Parasitol. 2004 Feb;90(1):67-71. doi: 10.1645/GE-110R.
Toxoplasma gondii isolates can be grouped into 3 genetic lineages. Type I isolates are considered more virulent in outbred mice and have been isolated predominantly from clinical cases of human toxoplasmosis, whereas types II and III isolates are considered less virulent for mice and are found in humans and food animals. Little is known of genotypes of T. gondii isolates from wild animals. In the present report, genotypes of isolates of T. gondii from wildlife in the United States are described. Sera from wildlife were tested for antibodies to T. gondii with the modified agglutination test, and tissues from animals with titers of 1:25 (seropositive) were bioassayed in mice. Toxoplasma gondii was isolated from the hearts of 21 of 34 seropositive white-tailed deer (Odocoileus virginianus) from Mississippi and from 7 of 29 raccoons (Procyon lotor); 5 of 6 bobcats (Lynx rufus); and the gray fox (Urocyon cinereoargenteus), red fox (Vulpes vulpes), and coyote (Canis latrans) from Georgia. Toxoplasma gondii was also isolated from 7 of 10 seropositive black bears (Ursus americanus) from Pennsylvania by bioassay in cats. All 3 genotypes of T. gondii based on the SAG2 locus were circulating among wildlife.
刚地弓形虫分离株可分为3个遗传谱系。I型分离株在远交系小鼠中被认为更具毒力，且主要从人类弓形虫病临床病例中分离得到，而II型和III型分离株对小鼠的毒力较低，在人类和食用动物中发现。关于野生动物来源的刚地弓形虫分离株的基因型知之甚少。在本报告中，描述了美国野生动物来源的刚地弓形虫分离株的基因型。用改良凝集试验检测野生动物血清中的抗刚地弓形虫抗体，并对抗体效价为1:25（血清阳性）的动物组织在小鼠中进行生物测定。从密西西比州34只血清阳性白尾鹿（弗吉尼亚鹿）中的21只心脏、29只浣熊（北美浣熊）中的7只、6只短尾猫（北美短尾猫）中的5只以及佐治亚州的灰狐（灰狐属）、赤狐（赤狐）和郊狼（犬属）中分离出刚地弓形虫。通过在猫中进行生物测定，还从宾夕法尼亚州10只血清阳性黑熊（美洲黑熊）中的7只中分离出刚地弓形虫。基于SAG2基因座的刚地弓形虫所有3种基因型都在野生动物中传播。
