Prenatal toxoplasmosis diagnosis from amniotic fluid by PCR

• Main Authors: Paula Vieira Teixeira Vidigal, Daniel Vítor Vasconcelos Santos, Flávia Cipriano Castro, Júlio César de Faria Couto, Ricardo Wagner de Almeida Vitor, Geraldo Brasileiro Filho
• Format: Article in Journal/Newspaper
• Language: English
• Published: Sociedade Brasileira de Medicina Tropical (SBMT) 2002
• Subjects: Congenital toxoplasmosis; PCR; Amniotic fluid; Arctic medicine. Tropical medicine; RC955-962; Arctic
• Online Access: https://doaj.org/article/7b3a5fd9c81f4ea89e8d5ba1bc0c18c3

Toxoplasmosis is one of the most common infections all over the world. Most cases are asymptomatic, except in immunosuppressed individuals and fetuses, which can be seriously damaged. Prenatal diagnosis should be made as soon as possible since treatment of the mother can minimize fetal sequelae. Our aim in this study was to test the polymerase chain reaction technique (PCR) in 86 samples of amniotic fluid from women who seroconverted during pregnancy. DNA was amplified using external primers and, in a second step, internal primers, in a nested PCR system. Samples were also inoculated into mice and the newborn were evaluated by T. gondii serology, skull x-ray, transfontanel ultrasound, fundoscopic examination, lumbar puncture and clinical examination. PCR was positive in seven cases and negative in 79. Among PCR-positive cases, two were negative by inoculation into mice and by clinical evaluation; among PCR-negative ones, three had clinical evidence of toxoplasmosis and one was positive after inoculation into mice. PCR showed values of sensitivity = 62.5% and specificity = 97.4%; the values of inoculation into mice where 42.9% and 100%, respectively. Although PCR should not be used alone for prenatal diagnosis of congenital toxoplasmosis, it is a promising method and deserves more studies to improve its efficacy.