Jorge R. Postigo

Congenital Chagas disease: diagnostic and clinical aspects in an area without vectorial transmission, Bermejo, Bolivia.

The authors carried out a 1-year study of a population of pregnant women delivering at Bermejo hospital, South Bolivia. In this area, vectorial transmission of Trypanosoma cruzi is negligible and women infect themselves during displacements in close endemic areas. The prevalence of T. cruzi in 508 pregnant women, diagnosed by several serological tests, was 33.9%. In eight infants, we observed T. cruzi in the umbilical cord (congenital transmission rate of 5.2%). The means of birth weights, lengths and hemoglobin rates were similar in the children from both seronegative and seropositive women, and in children infected or not by T. cruzi. This study could confirm a less severity of the congenital disease of Chagas in the absence of re-infestation of the mother during pregnancy. Serological screening of pregnant women by rapid diagnostic tests and examination of babies born from seropositive mothers by microhematocrit method at birth is a suitable strategy to detect and prevent congenital Chagas disease in non-endemic areas.

Risk factors and consequences of congenital Chagas disease in Yacuiba, south Bolivia

Objective  To determine the risk factors of congenital Chagas disease and the consequences of the disease in newborns.

Epidemiological evaluation of Chagas disease in a rural area of southern Bolivia.

We evaluated the prevalence of Chagas disease using a rapid screening test (Chagas Stat-Pak), confirmed by ELISA, in Caraparí, a village of 9000 inhabitants in southern Bolivian Chaco. The prevalence of Trypanosoma cruzi was estimated in a sample of 995 people. The prevalence adjusted on age was 51.2% and was proportionally related to age. We also observed a very significant cline from the south to the north of the locality, where the prevalence ranged from 40 to 80%. In children younger than 11 years, the prevalence was 21.5%, which confirmed the importance of residual vector transmission despite several years of vector control. Among women of procreation age, the prevalence was 63.9%, resulting in a high risk of congenital transmission. The control of the disease requires an increase in vector control and improvement of dwellings before considering childrens treatment with trypanocide.

Antibody drop in newborns congenitally infected by Trypanosoma cruzi treated with benznidazole

Objective  To compare the drop of Chagas antibody titres between non‐infected and congenitally infected newborns treated by two doses of benznidazole, aiming at evaluating the recovery time and giving recommendations regarding serological criteria of recovery.

Sensitivity and specificity of Chagas Stat-Pak test in Bolivia.

Objective  To compare the results of an immunochromatographic test performed on whole blood, Chagas Stat‐Pak®, with those of an ELISA test using recombinant antigens.

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.

Prevalence of Chagas disease in pregnant women and incidence of congenital transmission in Santa Cruz de la Sierra, Bolivia.

Congenital transmission of Chagas disease stand out as a major public health problem since the vector control was performed in all endemic areas and has shown its effectiveness. An epidemiological study was performed in three maternity hospitals of the city of Santa Cruz de la Sierra, Bolivia from 2006 to 2008. The serological screening for Trypanosoma cruzi infection was carried out in 15,767 pregnant women. Chagas infection was detected in 3725 women (23.6%), who gave birth to 125 newborns infected by T. cruzi at birth, representing an incidence of 790 per 100,000 births during a period of 16 months and a vertical transmission rate by 3.4%. There was a significant difference between hospitals that might be explained by socio-economic origins of mothers and diagnostic constraints.

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.