Abstract
BackgroundChagas disease, or American trypanosomiasis, is an important neglected tropical illness caused by the flagellate protozoan Trypanosoma cruzi, which is primarily transmitted to humans by hematophagous insects of the subfamily Triatominae. Although knowledge on triatomine movement capabilities at the micro-geographical scale is of fundamental importance concerning the development of effective vector control strategies, it remains a poorly understood subject. Furthermore, survival rates and size estimates of natural populations are important topics to consider when evaluating transmission intensity.ResultsThe movement of adult Triatoma sordida within the peridomestic area of a rural Brazilian household was evaluated via mark-release-recapture assays. A total of 210 insects had their pronota marked with fluorescent dyes and were released at different distances from the chicken coop (two, five, ten and 20 m), and from the horse corral (27, 32, 35, 46 and 56 m). Recaptures occurred in three consecutive 15-day intervals. Specimens were successfully recaptured at all distances up to 32 m. Bayesian models were used to estimate recapture probability, survival rates (males vs females) and population size. Although recapture probability was inversely proportional to distance for both sexes, females were more affected by increased distance. On the other hand, no significant difference was detected in the survival rates between males and females in a 15-day period. Fisher-Ford and Bayesian models gave more accurate population size estimates than Lincoln method.ConclusionsTriatoma sordida adults were able to cover a distance of 32 m in 45 days. Recapture data modelling reveals that male dispersal was more effective suggesting that T. sordida males are more likely to contribute as potential colonizers of the peridomestic environment. Increasing the distance between the peridomestic structures and the sylvatic environment as much as possible appears to be a simple and feasible recommendation to reduce the contact rate between humans and infected bugs and ultimately Chagas disease transmission.
Highlights
Chagas disease, or American trypanosomiasis, is an important neglected tropical illness caused by the flagellate protozoan Trypanosoma cruzi, which is primarily transmitted to humans by hematophagous insects of the subfamily Triatominae
Chagas disease, or American trypanosomiasis, is an important neglected tropical disease caused by the flagellate protozoan Trypanosoma cruzi
Triatoma sordida (Stål, 1859) is the Chagas disease vector most frequently captured in the peridomestic environment in Brazil, in areas where Triatoma infestans (Klug, 1834) has been eliminated by the Southern Cone Initiative [8, 9]
Summary
American trypanosomiasis, is an important neglected tropical illness caused by the flagellate protozoan Trypanosoma cruzi, which is primarily transmitted to humans by hematophagous insects of the subfamily Triatominae. American trypanosomiasis, is an important neglected tropical disease caused by the flagellate protozoan Trypanosoma cruzi This pathogen is most commonly transmitted to humans via the contact of infected faeces of hematophagous insects of the subfamily Triatominae (Hemiptera: Reduviidae) with the host’s mucous membranes [1, 2]. Other modes of transmission that have recently received attention include blood transfusion and ingestion of contaminated fruit juices [3, 4] The former has led to the dissemination of the disease to developing countries where there is no transmission cycle, such as Spain and Japan [5, 6], and the latter has contributed to the generation of acute per os micro-epidemics in rural areas of northern Brazil [7]. There is information available on the genetic structure and dispersal capabilities of T. sordida populations from Bolivia and Brazil at the macrogeographical level (inferred based on molecular markers, e.g. [10,11,12,13]), very little is known about small-scale triatomine dispersal (e.g. [14, 15])
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