Polymerase Chain Reaction in Cerebrospinal Fluid for the Diagnosis of Congenital Toxoplasmosis

Background: Congenital toxoplasmosis can result in visual impairment, hearing loss, serious neurologic sequelae and death in the infant. We studied the potential of the polymerase chain reaction (PCR) in cerebrospinal fluid (CSF) for diagnosis of congenital toxoplasmosis. Methods: For this purpose, we studied both congenitally infected (diagnosed clinically and serologically) and noninfected infants born to untreated mothers. Results: The infants ranged in age from 0 to 180 days. CSF PCR was positive in 27 of the 58 (46.5%) congenitally infected infants and was negative in each of the 103 infants without congenital toxoplasmosis. The frequency of positive CSF PCR varied according to whether infants had major clinical signs of the disease; PCR was positive in 70.9%, 53.3% and 50.9% of those with hydrocephalus, cerebral calcifications and/or eye disease, respectively. Of 6 infants who were negative for both IgM and IgA antibodies, 3 had a positive PCR in their CSF as the confirmatory test for diagnosis of congenital toxoplasmosis. IgM and IgA antibodies and CSF PCR, when combined, yielded a higher sensitivity for diagnosis of congenital toxoplasmosis when compared with the performance of each test alone. Conclusions: Our findings reveal that in infants with clinical and serologic findings suggestive of congenital toxoplasmosis and born to untreated mothers, CSF PCR has the potential to increase the frequency of cases in which the diagnosis is confirmed.