Congenital toxoplasmosis is a zoonotic protozoan infection caused by the intracellular coccidian
(phylum Apicomplexa) Toxoplasma gondii (T. gondii), which has a worldwide distribution.
All warm-blooded animals are susceptible to infection and about 30% of the world's population
is affected. The organism is transmitted transplacentally; following initial maternal infection,
vertical transmission occurs from an infected pregnant mother to her fetus, mostly in the third
trimester of pregnancy. The severity of fetal infection is determined by the pregnancy stage and
whether the infected mother had received an efficient treatment in the early gestational period or
not.
A better prognosis is expected for children whose mothers were treated with anti-Toxoplasma
medications. Some factors favor infection transmission and progress of congenital toxoplasmosis
as the parasite genotype, the immune status of the mother and the fetal or neonatal ability
to develop an immune response against Toxoplasma. Possible outcomes of fetal infection include
abortion, intrauterine growth retardation, jaundice, hepatosplenomegaly or intrauterine fetal
death. Nervous system complications like intracranial calcifications or hydrocephalus as well
as retinochoroiditis are all possible consequences. Commonly, there are no specific symptoms at
birth and complications may appear at an older age. Congenital toxoplasmosis is treated by
spiramycin in pregnant women, while, drugs were used during late gestation to benefit infected
fetus and are also used to treat the newborn after birth.