Attenuated Trypanosoma Cruzi Infection in Young Rats Nursed on Infected Mothers Undergoing Interferon-Gamma Treatment During Pregnancy

After defining some concepts, this chapter specifies the epidemiological features of this peculiar transmission mode of Trypanosoma cruzi. The possible maternal–fetal routes, the placental responses to parasite infection and the timing of transmission are reviewed in depth. The factors susceptible to be involved in parasite transmission and development of congenital Chagas disease, such as parasite genotypes and maternal and fetal immune responses, are discussed in detail. Information obtained from vertical transmission in other mammals is also examined. T. cruzi congenital infection is frequently asymptomatic, whereas reported symptoms are nonspecific, and severe and mortal clinical forms are mainly observed in case of maternal coinfection with HIV. The long-term consequences of congenital infection, such as the transgenerational transmission and the imprinting of neonatal immune system are also mentioned. The diagnosis of infection in pregnant women requires standard serological investigations. The laboratory diagnosis in newborns of positive mothers includes the use of parasitological techniques at birth or in the first months of life (though of limited sensitivity, these tests indisputably confirm the presence of live parasites) and/or standard serological investigations 8 months after birth, when maternal transmitted antibodies have disappeared. The conditions of using polymerase chain reaction (detecting parasitic DNA and not live parasites) are discussed in depth. All diagnosed congenital cases have to be treated before 1 year of age in order to cure them without side effects. Since the treatment of infected pregnant women is not recommended, the control strategy of congenital infection refers to its systematic detection in newborns of infected mothers by the means mentioned above.