Toxoplasmosis is the most prevalent zoonosis in the world and is associated with a large spectrum of diseases. Acute acquired toxoplasmosis (AAT) is considered a benign and self-limiting disease but severe postnatal infections have been reported, particularly in South America. Laboratory diagnosis is based on the detection of anti–Toxoplasma gondii IgM, IgG, and presence of low IgG avidity. However, these assays present limitations, and therefore, PCR has been suggested as an alternative diagnostic tool. In this study, we performed real-time and nested PCR in DNA blood samples from 59 individuals with AAT lasting less than 80 days. None of the patients had parasitic DNA detected by PCR, even in the more severe cases or when blood was collected early after disease onset. These negative results indicate that the parasitemia kinetics needs investigation to determine the best time for blood sampling, especially in immunocompetent individuals. Thus, we emphasize that a negative PCR result does not exclude recent T. gondii infection, and serological criteria are still decisive for the laboratory diagnosis of AAT.

弓形虫病是世界上最普遍的人畜共患病，与多种疾病有关。急性获得性弓形虫病（AAT）被认为是一种良性和自限性疾病，但已报道严重的产后感染，特别是在南美。实验室诊断基于对弓形虫的检测IgM，IgG和低IgG亲和力的存在。但是，这些测定法存在局限性，因此，PCR被建议作为一种替代的诊断工具。在这项研究中，我们对59名AAT持续不到80天的个体的DNA血液样本进行了实时和巢式PCR。即使在更严重的情况下或在疾病发作后早期采集血液的情况下，也没有患者通过PCR检测到寄生DNA。这些阴性结果表明，需要对寄生虫血症动力学进行研究以确定最佳的采血时间，尤其是在具有免疫能力的个体中。因此，我们强调PCR阴性结果不能排除刚弓形虫的近期感染，血清学指标对于AAT的实验室诊断仍具有决定性作用。