Application of polymerase chain reaction to the diagnosis of congenital toxoplasma and herpes simplex virus infection

ABSTRACT

Because Polymerase Chain Reaction [PCR] is a sensitive, rapid and specific method, we applied it on the sera and CSF of 42 patients in whom congenital toxoplasmosis or herpes simplex virus infection were suspected clinically seeking for a rapid and better diagnostic approach for these treatable congenital infections in order to minimize their morbidity and mortality by early therapeutic intervention . PCR was also applied on the sera of 12 mothers, the CSF and sera of 10 controls. HSV1 IGM antibody was performed by enzyme linked immunoassay [EIA] on all samples. HSVDNA was detected successfully by PCR in serum and CSF samples of 32/42 patients [16/21 neonates, 76.2% ; 16/21 infants 76.2%] and in the sera of 9/12 mothers, while HSV[1] IGM antibodies were positive in 21/42 cases, 50% [9/21 neonates, 42.8% ; 11/21 infants 52.3%] with a sensitivity of 70.8% and 41.2% for serum and CSF respectively while specificity was 100% for both samples [PCR isa golden standard method 100%]. PCR proved to be superior to serology detecting 11 additional cases with congenital HSV infection. SO, PCR. could be usefull for the confirmative diagnosis of congenital HSV infection especially in serologically negative cases. Concerning toxoplasmosis, the system adopted in this study using the P30 gene failed to detect toxoplasma DNA in the serum and CSF samples of ail studied cases. Therefore, for adequate laboratory diagnosis of toxoplasmosis, combination of several different test systems including immunoblot technique in addition to PCR and usage of at least 2 different toxoplasma gondii strains as antigens is mandatory