Departamento de Medicina Veterinária Preventiva, Laboratório de Protozoologia Animal, Universidade Estadual de Londrina - UEL, Londrina, PR, Brasil.
Rev Bras Parasitol Vet. 2021 Dec 1;30(4):e016621. doi: 10.1590/S1984-29612021091. eCollection 2021.
Felines are definitive hosts of Toxoplasma gondii and can shed oocysts in their feces, contaminating the environment. Sporulated oocysts are highly resistant to the environment and have higher infectivity, which are attributed to many toxoplasmosis outbreaks. The aim of the present study was to evaluate a quantitative polymerase chain reaction (qPCR) technique for the detection of T. gondii oocysts shed by cats. Twelve cats from a previous vaccine experiment were challenged orally with 600 cysts of the TgDoveBr8 strain on day 72. Fecal samples were collected daily using the centrifugal flotation technique, with microscopic examination (Sheather technique) and qPCR for 20 days after the challenge. Cats from all groups shed oocysts in their feces. Five negative cats in the Sheather were positive according to qPCR on the 3rd day post-inoculation (dpi). Oocysts were detected on the 4th dpi using the Sheather; however, there was no statistical difference between the two methods (p=0.1116). In addition, there was no statistically significant difference in oocyst shedding between the groups according to the Sheather technique (p=0.6534) and qPCR (p=0.9670). In conclusion, these results demonstrate that qPCR can be used as an alternative to the Sheather to detect and quantify T. gondii oocysts.
猫科动物是刚地弓形虫的终末宿主，其粪便中可排出卵囊，污染环境。孢子化卵囊对环境具有很强的抵抗力，感染性更高，这归因于许多弓形体病的爆发。本研究旨在评估一种定量聚合酶链反应（qPCR）技术，用于检测猫科动物排出的刚地弓形虫卵囊。在第 72 天，用 600 个 TgDoveBr8 株孢子化卵囊对来自先前疫苗实验的 12 只猫进行口服攻毒。攻毒后 20 天内，每天使用离心漂浮技术收集粪便样本，进行显微镜检查（Sheather 技术）和 qPCR 检测。所有组的猫粪便中均排出卵囊。在 Sheather 中，有 5 只阴性猫在接种后第 3 天 qPCR 呈阳性。在第 4 天使用 Sheather 检测到卵囊；然而，两种方法之间没有统计学差异（p=0.1116）。此外，根据 Sheather 技术（p=0.6534）和 qPCR（p=0.9670），各组之间的卵囊排出量没有统计学差异。总之，这些结果表明 qPCR 可作为替代 Sheather 检测和定量刚地弓形虫卵囊的方法。
