Detectable Trypanosoma cruzi Parasitemia during Pregnancy and Delivery as a Risk Factor for Congenital Chagas Disease

Abstract

Vector control has led to a drastic decrease in the prevalence of acquired Chagas disease in Latin America, thus redirecting attention to congenital Chagas disease. We report results of a longitudinal study of 359 pregnant women in Yacuiba in southern Bolivia, of whom 147 (40.9%) were infected with Trypanosoma cruzi, to evaluate the relationship between the patency period of the parasitemia and the risk of congenital infection. Maternal infection was assessed by using T. cruzi-specific serologic tests, and parasitemia in mothers and newborns was diagnosed by using microscopic examination of blood in heparinized microhematocrit tubes. Parasitemia was present in 28.6% of the infected women. Its prevalence increased during the third trimester, then decreased at delivery. The likelihood of congenital infection was significantly correlated with the parasite density in the mother's blood. The risk of transmission increased during the third trimester of pregnancy and could explain premature births or low-weight newborns for infected mothers.

2 nd Brazilian Consensus on Chagas Disease, 2015

“…The transmission may occur at any time during pregnancy, possibly being greater in the third quarter, with increasing parasitemia (116) (118) . On the other hand, the timely diagnosis of infection during pregnancy allows a more qualified care to the infected pregnant women, who should be monitored throughout gestation.…”

Influence of Pregnancy on Trypanosoma cruzi Parasitemia in Chronically Infected Women in a Rural Bolivian Community

“…Pregnant women also had a higher rate of T. cruzi parasitemia than non-pregnant women (14.9 versus 2.9%, respectively, RR 5.2 95% CI = 1.5-18.1; P = 0.004, Table 1 ). Mean parasite densities were also higher for the 10 pregnant parasitemic women (45 parasites/mL, range 5-230) than for the 3 non-pregnant parasitemic women (10 p/mL, range [5][6][7][8][9][10][11][12][13][14][15]. Because of the reduced sample size, this difference did not reach statistical significance.…”

“…[4][5][6] In a cohort of Bolivian women chronically infected by T. cruzi , nearly 30% of the women presented with parasites in the bloodstream, and parasitemia tended to increase from the first to the third trimester and then decrease at delivery. 7 During pregnancy, a systemic shift toward Th2 dominance and suppression of cell-mediated immunity may contribute to increased susceptibility to intracellular pathogens. Indeed, the hormonal environment of pregnancy contributes to local suppression of cytotoxic T lymphocyte responses at the maternal-fetal interface and the release of Th2 stimulating cytokines, which activate B lymphocytes and stimulate antibody secretion.…”

Compromiso ocular en la enfermedad de Chagas congénita

“…7,8 El riesgo de transmisión transplacentaria aumenta con la progresión del embarazo; es mayor durante el tercer trimestre, lo que podría explicar los nacimientos prematuros y el bajo peso de los niños de las mujeres infectadas. 9 El diagnóstico en la embarazada es clave, ya que, además, permite el estudio del recién nacido, cuyo diagnóstico temprano favorece la evolución y la curación sin secuelas.…”