Insect vectors of Chagas disease (Trypanosoma cruzi) in Northeastern Brazil

Abstract INTRODUCTION: Chagas disease remains a public health problem in the rural and urban areas of 19 countries in the Americas. METHODS: The aim of the present study was to investigate the Trypanosoma cruzi infection rate of triatomines collected from both intra- and peridomiciliary areas in eleven municipalities of Southeastern Ceará, Brazil, from 2009 to 2015. RESULTS: A total of 32,364 triatomine specimens, including nymphs and adults, were collected, and 31,736 (98.06%) of these were examined. More nymphs were collected than adults, and the greatest number of triatomines (n = 8,548) was collected in 2010, for which the infection rate was 1.3%, with the highest rate of infections observed for specimens from Quixere. The species collected during the study were identified as Triatoma pseudomaculata, Triatoma brasiliensis, Panstrongylus megistus, Panstrongylus lutzi, and Rhodnius nasutus, with T. pseudomaculata being the most abundant (n = 19,962). CONCLUSIONS: These results verify the presence of triatomines in both intra- and peridomiciliary areas, thereby ensuring persistence of the pathogen and consequently, the disease, as the presence of infected vectors in households is an important risk factor. According to these findings, the Chagas Disease Control Program should intensify its efforts in order to prevent the spread of the disease.

Analysis of the seroprevalence of and factors associated with Chagas disease in an endemic area in Northeastern Brazil

ABSTRACT INTRODUCTION: Chagas disease (CD) is currently considered a neglected disease; hence, identifying the factors associated with its high prevalence is essential. This study aimed to identify the seroprevalence of and the possible factors associated with CD in inhabitants of the City of Limoeiro do Norte, Northeastern Brazil. METHODS: Between April and November 2013, blood collection was conducted and a semi-structured questionnaire was administered. Blood samples that showed positive or possible serology for anti-Trypanosoma cruzi antibodies based on indirect immunofluorescence, hemagglutination indirect, and an enzyme-linked immunosorbent assay were analyzed. Associations between CD positivity and the study variables were analyzed using prevalence ratios (PR) with 95% confidence intervals (CI). RESULTS: A total of 812 individuals were analyzed, of which T. cruzi seropositivity was determined in 4.2% (34 individuals). Sociodemographic variables showing a significant association with T. cruzi positivity included age >50 years (PR = 27.6; 95% CI = 6.66-114.4), elementary level education (PR = 5.15; 95% CI = 1.83-14.47), and retirement (PR = 7.25; 95% CI = 3.72-14.14). Positivity for T. cruzi was 6.17 times higher in those who had a history of living in rammed earth houses compared with those who did not (95% CI = 2.19-17.37). There was no evidence of vertical transmission in the individuals studied. Among the individuals infected with T. cruzi, the majority reported having a comorbidity (p < 0.01). CONCLUSIONS: This study demonstrated the seroprevalence of CD and identified factors associated with a high prevalence of CD.

Doença de Chagas: situação vetorial no município de Limoeiro do Norte – CE, no período de 2006 a 2009 / Chagas Disease: vector status in the city of Limoeiro do Norte – CE, during the period from 2006 to 2009

Entre as doenças transmitidas por vetores no Brasil, a doença de Chagas é uma das mais importantes como problemas de saúde pública. Neste estudo foi estimada a prevalência de triatomíneos infectados por Trypanosoma cruzi no município de Limoeiro do Norte-CE, por meio de consulta aos arquivos do Programa de Controle da Doença de Chagas deste Distrito Sanitário no período de 2006 a 2009. Na análise foram incluídos os triatomíneos adultos e ninfas, mortos ou vivos, capturados durante o período investigado. Durante os quatro anos de estudo foram capturados 2.863 exemplares de triatomíneos, ninfase adultos distribuídos no intradomicílio e peridomicílio; e examinados 2.756 (96,3 %) exemplares. O índice de infecção dos triatomíneos foi de 7,9 % nos quatros anos de estudo. O número de ninfas capturadas foi cerca de três vezes maior que o número de adultos; no entanto, o número de ninfas infectadas pelo flagelado (5,30 %) foi inferior aos adultos (15,85 %). O distrito de Limoeiro do Norte apresenta alto risco de transmissão para doença de Chagas e, portanto, sugere-se que as ações de controle sejam intensificadas neste município para evitar a ocorrência de transmissão da doença e dispersão do vetor.

In Brazil, among the endemic vector-borne diseases, Chagas disease has been considered one of the mostimportant public health problems. The present study aimed at estimating the prevalence of triatominesinfected with Trypanosoma cruzi in the city of Limoeiro do Norte, CE, Brazil. This investigation was conductedby consulting the archives of the Chagas disease control program of the Health District of Limoeiro do Nortefor the period from 2006 to 2009. The study included dead or alive, adults and nymphs triatomines, whichwhere captured during the investigated period. During the four-year study, 2,863 specimens of nymphs andadults insects were captured from the domestic and peridomestic areas; 2,756 were examined, representing96.3 % of collected specimens. The insect infection rate was 7.9 % in four-year study. The number of capturednymphs was nearly three times higher than the number of adults; however the number of nymphs infectedwith the flagellate (5.30 %) was lower than the number of adults form (15.85 %). Limoeiro do Norte showeda high risk for Chagas disease transmission, suggesting that the control actions should be intensified in thiscity to prevent the disease transmission and the vector spread.