Parasites and fungi as a threat for prenatal and postnatal human development

Abstract

Recent literature data reveals the most common etiological agents of congenital parasitoses to be Toxoplasma gondii, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum. An analysis of clinical data indicates that parasitic congenital infections are often asymptomatic, whereas symptomatic newborns usually display nonspecific symptoms, which greatly hinders correct diagnosis. The long-term consequences of prenatal infections are serious clinical problems. This article presents the possible routes of vertical transmissions (mother-to-child) of pathogens including prenatal, perinatal, as well as postnatal routes. It highlights the role of factors involved in protozoa transmission and development of congenital parasitic diseases, such as parasite genotypes, the relationship between the timing of maternal infection and the probability of passage of the parasite through the placental barrier, and the immunological features of pregnant women. Acquired and congenital babesioses in human and experimental animals are presented. It emphasises that the mechanisms by which parasites infect the placenta and cross from mother to fetus are still poorly understood. It also describes the cellular mechanisms of infection by T. gondii, such as tachyzoites crossing biological barriers, the expression of Toll-Like Receptors (TLR) family on trophoblasts and syncytiotrophoblasts as an immune response to intrauterine infection and cases of congenital and acquired toxoplasmosis, as well as the long-term consequences of congenital invasion with T. gondii, episodes of reactivation of latent toxoplasmosis and T. gondii reinvasions. Mycological topics include a rare case of in utero fungal infection of offspring by a mother with vaginal candidosis, and the fungal contamination of ward facilities and medical equipment as potential sources of exogenous infections of newborn children.