Assessing the vulnerability of Brazilian municipalities to the vectorial transmission of Trypanosoma cruzi using multi-criteria decision analysis

Abstract

Despite the dramatic reduction in Trypanosoma cruzi vectorial transmission in Brazil, acute cases of Chagas disease (CD) continue to be recorded. The identification of areas with greater vulnerability to the occurrence of vector-borne CD is essential to prevention, control, and surveillance activities. In the current study, data on the occurrence of domiciliated triatomines in Brazil (non-Amazonian regions) between 2007 and 2011 were analyzed. Municipalities' vulnerability was assessed based on socioeconomic, demographic, entomological, and environmental indicators using multi-criteria decision analysis (MCDA). Overall, 2275 municipalities were positive for at least one of the six triatomine species analyzed (Panstrongylus megistus, Triatoma infestans, Triatoma brasiliensis, Triatoma pseudomaculata, Triatoma rubrovaria, and Triatoma sordida). The municipalities that were most vulnerable to vector-borne CD were mainly in the northeast region and exhibited a higher occurrence of domiciliated triatomines, lower socioeconomic levels, and more extensive anthropized areas. Most of the 39 new vector-borne CD cases confirmed between 2001 and 2012 in non-Amazonian regions occurred within the more vulnerable municipalities. Thus, MCDA can help to identify the states and municipalities that are most vulnerable to the transmission of T. cruzi by domiciliated triatomines, which is critical for directing adequate surveillance, prevention, and control activities. The methodological approach and results presented here can be used to enhance CD surveillance in Brazil.

2 nd Brazilian Consensus on Chagas Disease, 2015

“…Despite the advances, the risk of vectorial transmission of Chagas disease persists. This has been evaluated from different perspectives (22) , including the existence of indigenous species of triatomine with high potential for colonization; the presence of T. cruzi reservoirs and increasing proximity of human populations to these environments; and the persistence of residual foci of T. infestans, still existing in some municipalities of the States of Bahia and Rio Grande do Sul (22) (23) (39) (67) . The impacts of the certification process achieved by Brazil in 2006 in relation to T. infestans generated concern about the demobilization of society in general and the imprecise way information was obtained and disclosed to society (68) .…”

“…From this perspective, identifying areas with greater vulnerability to the synanthropic occurrence of triatomine has been important tool to reorient prevention, control, and surveillance actions (39) (67) , and to optimize the use of available program resources (20) . On the other hand, risk stratification associated with vector transmission has been proposed as an important strategy for the guidance and support of control measures in the country and has been incorporated, in different ways, by the control programs of states and municipalities (4) (20) (22) (39) (65) .…”

“…Currently, the risk related to the transmission of T. cruzi in Brazil depends mainly on: I) the persistence of residual foci of T. infestans, with episodes found in some states, such as Bahia and Rio Grande do Sul; II) the existence of large number of species that were confirmed as indigenous or acting as potential vectors in the country, even though in some cases resident populations have been greatly reduced; III) the emergence of new species at risk of domiciliation (T. rubrovaria, P. lutzi); IV) the existence of endemic transmission in the Amazon Region, with still poorly characterized mechanisms of transmission such as domiciliary vectorial without colonization, extradomiciliary vectorial, and oral; and V) the occurrence of outbreaks and micro-epidemics of orally transmitted of T. cruzi infection (20) (33) (65) (67) .…”

“…The major change in the epidemiological situation of the disease in the country has generated the need for a dynamic review of the control strategies adopted (4) (20) (23) (33) (65) (67) . From this perspective, identifying areas with greater vulnerability to the synanthropic occurrence of triatomine has been important tool to reorient prevention, control, and surveillance actions (39) (67) , and to optimize the use of available program resources (20) .…”

Synanthropic triatomines as potential vectors of Trypanosoma cruzi in Central Brazil

“…Thaís Tâmara Castro Minuzzi-Souza [1] , Nadjar Nitz [2] , César Augusto Cuba Cuba [1] , Marcelo Santalucia [3] , Monique Knox [4] , Luciana Hagström [2] , Camilla Bernardes Furtado [1] , Tamires Emanuele Vital [2] , Marcos Takashi Obara [1] , Mariana Machado Hecht [2] and Rodrigo Gurgel-Gonçalves 5,6 .…”