Vector control intervention towards interruption of transmission of Chagas disease by Rhodnius prolixus, main vector in Guatemala

In Guatemala, the Ministry of Health (MoH) began a vector control project with Japanese cooperation in 2000 to reduce the risk of Chagas disease infection. Rhodnius prolixus is one of the principal vectors and is targeted for elimination. The control method consisted of extensive residual insecticide spraying campaigns, followed by community-based surveillance with selective respraying. Interventions in nine endemic departments identified 317 villages with R. prolixus of 4,417 villages surveyed. Two cycles of residual insecticide spraying covered over 98% of the houses in the identified villages. Fourteen villages reinfestated were all resprayed. Between 2000-2003 and 2008, the number of infested villages decreased from 317 to two and the house infestation rate reduced from 0.86% to 0.0036%. Seroprevalence rates in 2004-2005, when compared with an earlier study in 1998, showed a significant decline from 5.3% to 1.3% among schoolchildren in endemic areas. The total operational cost was US$ 921,815, where the cost ratio between preparatory, attack and surveillance phases was approximately 2:12:1. In 2008, Guatemala was certified for interruption of Chagas disease transmission by R. prolixus. What facilitated the process was existing knowledge in vector control and notable commitment by the MoH, as well as political, managerial and technical support by external stakeholders.

Seroprevalence of Trypanosoma cruzi infection in three rural communities in Guatemala / Seroprevalencia de infección por Trypanosoma cruzi en tres comunidades rurales de Guatemala

A systematic, house-based serological survey for Trypanosoma cruzi seroreactivity was conducted in three contiguous communities in Olopa municipality, Chiquimula Department, Guatemala. Blood samples from a total of 292 individuals in 63 households were examined by enzyme-linked immunosorbent assay. The seropositive rate ranged from 0 x cent to 20.8 x cent for the three communities, with a mean of 15.1 x cent. Log-linear models showed that seroprevalence was significantly related to age (P<0.005) but not to sex. However, when the age group with the lowest prevalence (1-9 years) was excluded from the analysis, age was not a significant factor (P=0.55). Data from a stratified sample collected at the same time were combined with those of the systematic sample to analyze the relationship between seropositivity and possible explanatory variables. Log-linear models, based on 586 individuals in 129 households from the two surveys, revealed a significant positive association between seropositivity and thatched roofs (P=0.01)

Una encuesta serológica sistemática y domiciliaria para detectar serorreactividad a Trypanosoma cruzi se llevó a cabo en tres comunidades contiguas de la municipalidad de Olapa, en el departamento de Chiquimula, Guatemala. Se examinaron mediante inmunoadsorción enzimática muestras de sangre obtenidas de un total de 292 habitantes que residían en 63 viviendas. La tasa de seropositividad varió de 0 a 20,8% en las tres comunidades y tuvo una media de 15,1%. Los modelos logarítmico-lineales mostraron una asociación significativa entre la seroprevalencia y la edad (P < 0,05), pero no entre aquella y el sexo. No obstante, cuando el grupo de edad que tuvo la seroprevalencia más baja (el de 1 a 9 años) se excluyó del análisis, la edad dejó de ser un factor significativo (P = 0,55). Datos obtenidos de una muestra estratificada recogida simultáneamente se combinaron con los de la muestra sistemática con el fin de analizar la relación entre la seropositividad y algunas variables que podrían ser explicativas. Los modelos logarítmico-lineales, aplicados en 586 habitantes de 129 viviendas incluidas en ambas encuestas, revelaron una asociación positiva significativa entre la seropositividad y la presencia de techo de paja (P = 0,01)