Molecular and serological study on congenital toxoplasmosis in newborn of Shiraz, Southern Iran

Toxoplasmosis is a zoonotic disease caused by an obligatory intracellular parasite, Toxoplasma gondii. The congenital form of the disease is a significant health problem around the world. This study aimed to determine the incidence of congenital toxoplasmosis in the newborn of Shiraz, Southern Iran, between 2013 and 2018. A total of 2498 blood samples of neonates were randomly collected by a standard heel puncture technique and dried on Guthrie cards from Shiraz newborn screening center. We provided questionnaire forms for mothers according to their demographic characteristics, such as age, place of residence, history of having cats as pet, and literacy level. ELISA immunocapture and PCR assays were applied to detect anti-Toxoplasma IgM and the parasite DNA in dried blood spot samples. The anti-Toxoplasma IgM antibody was detected in two out of the 2498 infants. Moreover, borderline titers were observed in 3 samples, which were considered suspicious, so these were retested after 18 months to detect IgG against Toxoplasma. Positive IgG titer was observed in two infants who had a positive IgM level. The genome of Toxoplasma was detected in one sample out of 2498. No significant differences were seen between the epidemiological factors with congenital infection. The incidence of congenital toxoplasmosis is estimated at 0.08% of studied samples. It seems that this incidence could present to the health ministry as a logical research achievement for the national screening program of newborns in Iran.