Optimizing the parasitological diagnosis of congenital toxoplasmosis

Abstract

Early diagnosis of Congenital Toxoplasmosis is highly important, since it can make the treatment possible and reduces sequela for the infant. Serological diagnosis alone cannot be accurate when it does not identify the IgA, IgM or IgG antibodies of low avidity, which do not cross the placent barrier. Therefore, parasitemic identification is important to be carried out by demonstrating the parasite in the peritoneal exsudatum of mice inoculated with suspected biological material, however such method is little sensitive and too much time-consuming. This research study aims at optimizing mice inoculation through serological screening, and encephalic histopathology, in order to identify whether there was contamination. Out of 138 fetuses and/or newborn samples taken from pregnant women positive for active toxoplasmosis inoculated intraperitoneally in mice, only 5 showed positive through parasite demonstration in the peritoneal exsudatum. Histopathology showed the agent in 45 cases and in 67 the presence of anti-toxoplasmas antibodies in the mice bloodstream by using indirect immunofluorescence technique. Mice serology and encephalic histopathology in addition to reducing the amount of time necessary for the outcomes from 120 to 60 days increased the positivity of 3.6% to 50.4% and 33.8%, respectively.