Toxoplasma gondii (T. gondii) is a protozoan parasite that reside majorly in the brain of its intermediate host. T. gondii infected rodents shows some degree of behaviour deficits, while T. gondii infection in humans is associated with psychiatric problems such as schizophrenia. The present study aimed to evaluate the effects of Malaysian strains of T. gondii on rats. Forty five, four weeks old, male Wistar rats were used. The rats were assigned into five groups: two control groups (CG1 and CG2) and three experimental groups (EG1, EG2, EG3). CG1 rats received phosphate buffered saline (PBS), CG2 received MK-801 (as a model for schizophrenia), EG1, EG2, EG3 received orally 5 x 103 single T. gondii oocysts strain of type I, type II and type III respectively. After infection, all the five groups of rats were tested for T. gondii antibodies at two weeks post-infection (PI). Behavioural tests of exploratory activity (open field) and spatial learning and memory retention (Morris water maze) were performed on the ninth and tenth weeks PI followed by histological staining of rat brain. T. gondii IgM antibodies were detected in EG1, EG2 and EG3, but not in CG1 and CG2. The behaviour results demonstrated that rats from CG2, EG1, EG2 and EG3 had increased in their locomotor activities and memory deficits compared to control, while learning remain intact. Moreover, tissue cysts were found widely distributed exclusively in the whole brain of EG1, EG2 and EG3 without tropism. These findings taken together, implies that Malaysian strains of T. gondii are implicated in some causes of behaviour changes that are responsible for schizophrenia-like conditions if humans were infected.

中文翻译：

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马来西亚弓形虫菌株对精神分裂症样大鼠行为的影响及其可能的风险

弓形虫（T. gondii）是一种原生动物寄生虫，主要存在于其中间宿主的大脑中。刚地弓形虫感染的啮齿动物表现出一定程度的行为缺陷，而人类中刚地弓形虫感染与精神分裂症等精神疾病有关。本研究旨在评估马来西亚弓形虫菌株对大鼠的影响。使用四十五，四周大的雄性Wistar大鼠。将大鼠分为五组：两个对照组（CG1和CG2）和三个实验组（EG1，EG2，EG3）。CG1大鼠接受磷酸盐缓冲盐水（PBS），CG2接受MK-801（作为精神分裂症的模型），EG1，EG2，EG3分别口服5 x 103个I型，II型和III型刚地弓形虫卵囊菌株。感染后，对所有五组大鼠进行T检验。感染后两周（PI）接受刚地抗体。在第9周和第10周进行探索性活动（开放视野）和空间学习与记忆保持（Morris水迷宫）的行为测试，然后对大鼠脑进行组织学染色。在EG1，EG2和EG3中检测到弓形虫IgM抗体，但在CG1和CG2中未检测到。行为结果表明，与对照组相比，来自CG2，EG1，EG2和EG3的大鼠运动能力和记忆缺陷增加，而学习则保持不变。此外，发现组织囊肿仅在EG1，EG2和EG3的整个大脑中广泛分布，而没有向心性。这些发现加在一起，表明马来西亚的T株。