Biological and genetic characterisation of Toxoplasma gondii isolates from chickens (Gallus domesticus) from Sao Paulo, Brazil:: unexpected findings
Biological and genetic characterisation of Toxoplasma gondii isolates from chickens (Gallus domesticus) from Sao Paulo, Brazil:: unexpected findings
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DOI：
10.1016/s0020-7519(01)00364-2
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发表时间：
2002-01-01
影响因子：
4
通讯作者：
Thulliez, P
中科院分区：
文献类型：
--
作者：
Dubey, JP;Graham, DH;Thulliez, P
尽管弓形虫宿主范围广，分布世界各地，但其遗传多样性却很低。大部分T.弓形虫可分为两到三个谱系。I型毒株被认为在远交实验室小鼠中具有高毒性，并且主要从人类弓形虫病的临床病例中分离，而II型和III型毒株被认为对小鼠无毒力。在本研究中，25个T.从巴西圣保罗周围农村地区无症状鸡中获得的弓形虫分离株为I型。抗T.用甲醛保存的弓形虫速殖子和巯基乙醇对82份鸡血清进行了弓形虫的改良凝集试验，其中32份血清的弓形虫滴度在1：10以上。22株T.用29只血清学阳性（大于或等于1：40）鸡的脑和心脏接种小鼠，通过生物测定获得弓形虫，从52只鸡的猫饲喂组织的粪便中获得三个分离株，
In spite of a wide host range and a world wide distribution, Toxoplasma gondii has a low genetic diversity. Most isolates of T. gondii can be grouped into two to three lineages. Type I strains are considered highly virulent in outbred laboratory mice, and have been isolated predominantly from clinical cases of human toxoplasmosis whereas types II and III strains are considered avirulent for mice. In the present study, 17 of 25 of the T. gondii isolates obtained from asymptomatic chickens from rural areas surrounding Sao Paulo, Brazil were type I. Antibodies to T. gondii were measured in 82 chicken sera by the modified agglutination test using whole formalin-preserved tachyzoites and mercaptoethanol and titres of 1:10 or more were found in 32 chickens. Twenty-two isolates of T. gondii were obtained by bioassay in mice inoculated with brains and hearts of 29 seropositive (greater than or equal to1:40) chickens and three isolates were obtained from the faeces of cats fed tissues from 52 chickens with no or low levels (