Description of an oral Chagas disease outbreak in Venezuela, including a vertically transmitted case

Abstract

We describe the eleventh major outbreak of foodborne Trypanosoma cruzi transmission in urban Venezuela, including evidence for vertical transmission from the index case to her fetus. After confirming fetal death at 24 weeks of gestation, pregnancy interruption was performed. On direct examination of the amniotic fluid, trypomastigotes were detected. T. cruzi specific-polymerase chain reaction (PCR) also proved positive when examining autopsied fetal organs. Finally, microscopic fetal heart examination revealed amastigote nests. Acute orally transmitted Chagas disease can be life threatening or even fatal for pregnant women and unborn fetuses owing to vertical transmission. There is therefore an urgent need to improve national epidemiologic control measures.

Fig. 1. : polymerase chain reaction (PCR) to detect Trypanosoma cruzi DNA in the maternal index case was performed on the peripheral blood (1), placenta (2-5), fetal liver (6), fetal spleen (7), fetal kidneys (8), and the amniotic fluid (9). Samples were positive for a 188-bp amplicon corresponding to the nuclear DNA sequence of T. cruzi. DNA amplification of the parasite in fetal kidneys and placenta exhibited greater band intensity when compared to other organs in which T. cruzi DNA was also detected. Positive (10) and negative controls are also shown (11). These assays demonstrate the presence of parasites in the tissue and circulation of the index patient and the fetus.

Fig. 2. : (A) anatomopathological evaluation revealed a 320 g macerated grade II, 20 ± 3-week-stillborn male fetus; (B) dissected and formalin-fixed fetal organs. Hepatomegaly and dystrophic calcifications of the liver parenchyma were noticed; (C) placental disk, with opaque green-yellowish membranes and macroscopic signs of acute chorioamnionitis and a hypermature placenta.