Evaluation of compliance to congenital Chagas disease treatment: results of a randomised trial in Bolivia.

BACKGROUND: A randomised, unblinded, clinical trial comparing two benznidazole regimens for congenital Chagas disease was carried out to determine whether simplification and reduction in the length of treatment could lead to better treatment compliance. METHODS: This study was conducted in Santa Cruz, Bolivia. Serological screening was carried out in pregnant women, and parasites were sought in the blood of newborns from seropositive mothers. Infected infants were randomly assigned to two treatment groups. Recovery was assessed by parasite seeking at 1 month and 2 months as well as serological tests at 9 months. Assessment of treatment adherence was based on weekly home visits and use of electronic monitors. RESULTS: Benznidazole was given to 63 newborns in group A (5 mg/kg in two daily doses for 60 days) and 61 newborns in group B (7.5 mg/kg in a single daily dose for 30 days). There was no difference in compliance between the two groups. The study confirmed the efficacy and good tolerance of both benznidazole regimens in the treatment of congenital Chagas disease. CONCLUSIONS: The short treatment should be preferred as it allows reducing the dose of benznidazole as well as the cost of treatment.

Influence of pregnancy on Trypanosoma cruzi parasitemia in chronically infected women in a rural Bolivian community.

To determine the role of pregnancy on Trypanosoma cruzi parasitemia, a matched cohort study was carried out in a rural Bolivian community comparing parasite rates in gravidae, puerperae, and non-pregnant infected women. A selection of 67 chronically infected women, who delivered between March 2004 and May 2005, were initially evaluated during the third trimester of pregnancy and again after delivery. They were matched for age, parity, and location with 104 seropositive non-pregnant women, who likewise had submitted blood for microscopic examination for T. cruzi parasites in June 2005. Seroreactive pregnant women had a higher rate of T. cruzi parasitemia (14.9%) than matched non-pregnant infected women (2.9%; P = 0.004). After delivery, parasitemia significantly decreased during puerperium (1.5%) compared with the period of pregnancy (14.9%; P = 0.03). This study showed an increase of parasite loads in maternal peripheral blood, during the third trimester, and a significant decline after delivery.

Door-to-door screening as a strategy for the detection of congenital Chagas disease in rural Bolivia.

OBJECTIVE: To demonstrate the feasibility of a house-to-house screening system used for congenital Chagas disease in rural areas based on an active search for pregnant women and newborns in their homes in addition to passive case detection in health facilities. METHODS: Exploratory phase conducted by the research team followed by an operational period coordinated by municipal health service. A blood sample was taken for serological and parasitological tests of Trypanosoma cruzi from pregnant women who were searching antenatal care or visited at home by field investigators. Infants born to T. cruzi-infected women were examined for infection at birth and again at 1 and 7 months of age. RESULTS: 64.5% of the pregnant women were infected. Congenital infection was diagnosed at birth in 4.0% (12/299) of the children born to seroreactive mothers. Twelve additional cases of infection (4%) were diagnosed in children between 1 and 7 months of age. Finally, 37% of the children were lost to follow-up in the exploratory phase and 53% during the operational phase (P=0.002), significantly fewer than in most passive case detection studies. CONCLUSION: Despite poorer outcomes after door-to-door screening activities have been transferred to the health system, a combined strategy based on active and passive case detection appeared to be efficient for identifying rural cases of congenital Chagas disease.

Detectable Trypanosoma cruzi parasitemia during pregnancy and delivery as a risk factor for congenital Chagas disease.

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.