The epidemiologic importance of Triatoma brasiliensis as a Chagas disease vector in Brazil:: a revision of domiciliary captures during 1993-1999

To clarify the epidemiologic importance of Triatoma brasiliensis, the most important Chagas disease vector ill the Northeastern of Brazil, capture data related to this species, its distribution, capture index, and percentages of natural infection by Trypanosoma cruzi were examined in 12 different states. The Brazilian National Health Foundation collected these data front 1993 to 1999, a period during which a total of 1,591,280 triatomines (21 species) were captured ill domiciles within the geographic range of T. brasiliensis. Of this total, 422,965 (26.6%) were T. brasiliensis, 99.8% of which were collected in six states, and 54% ill only one state (Ceara). The percentage of bugs infected with T. cruzi varied significantly among states, ranging from 0% (Goias, Maranhao, Sergipe, and Tocantins) to more than 3% (Alagoas, Minas Gerais, and Rio Grande do Norte) with all average of 1.3%. This latter value represents a dramatic reduction in the natural infection percentages since 1983 (6.7%) suggesting that, despite the impossibility of eradicating this native species, the control measures have significantly reduced the risk of transmission. However the wide geographic distribution of T. brasiliensis, its high incidence observed ill some states, and its variable percentages of natural infection by T. cruzi indicate the need,for sustained entomological surveillance and continuous control measures against this vector.