Behavioral plasticity of Triatominae related to habitat selection in northeast Brazil.

Triatoma pseudomaculata Corrêa and Espínola, 1964 and Triatoma juazeirensis Costa and Felix, 2007 ( = T. brasiliensis Neiva, 1911 [part]), are sylvatic vectors of Trypanosoma cruzi (Chagas, 1909), the causative agent of Chagas disease, in northeast Brazil-especially in the caatinga region. In an area of caatinga in the State of Bahia, we compared the wild and peridomestic habitats of these two species of Triatominae to assess their behavioral plasticity in relation to habitat selection in different environments. In the sylvatic environment, the habitat of these two species is never shared. T. pseudomaculata is found in trees and bird nests, but without apparent preference for any particular tree species. In contrast, T. juazeirensis is exclusively rupicolous (found among rocks). Both species invade peridomestic structures but do not display a significant ability to colonize human dwellings. In the peridomestic area, they are highly adaptable to different habitats and can occupy substrates that they do not colonize in the sylvatic environment. This behavioral plasticity seems to be more striking in T. juazeirensis-rupicolous in sylvatic environments but colonizing wooden structures in the peridomicile in >80% of cases.

Sylvatic Triatoma infestans (Reduviidae, Triatominae) in the Andean valleys of Bolivia.

Triatoma infestans is the main vector of Chagas disease in the Southern Cone countries. Wild populations of T. infestans appear widespread throughout the Andean valleys of Bolivia. In Cotapachi (2750 m asl), all sorts of rocky outcrops, regardless of their size, provided good refuges for T. infestans. Of the 1120 ecotopes investigated, 330 (29.5%) contained triatomines and 92% of the collected insects were nymphal instars. In the cold season, triatomine densities were similar in small and large outcrops. During the hot season, bug densities were higher in the larger outcrops, particularly in those located in peridomestic sites. T. infestans populations apparently produced one generation per year. Over half the sampled bugs were positive for T. cruzi infection. At Mataral (1750 m asl), a site located in the inter-Andean Chaco, a new morph of T. infestans was detected in a sylvatic environment.

[Conceptual approaches and methodological proposals for the study of interactions between environment and health: application to a research program on American trypanosomiasis]. / Enfoques conceptuales y propuestas metodológicas para el estudio de las interacciones entre el medio ambiente y la salud: aplicación a un programa de investigación sobre la tripanosomiasis americana.

Modifications of the landscape by human activity and migratory movements contribute to the emergence or reemergence of zoonotic and human diseases, particularly those transmitted by insects which often escape the changing environmental conditions, adapting and modifying their trophic networks and morphology, including their genotype. A better understanding of relationships between ecological factors, human factors, and anthropozoonoses is vital to be able to identify variables that allow one to map the risk for human populations. This is the main objective of the research program Landscape Ecology, Land-Use Dynamics, and Eco-Pathogenic Complexes: Eco-Epidemiologic Risk in the Case of American Trypanosomiasis, developed in various Brazilian ecosystems. The authors describe the program's conceptual and methodological basis and highlight the role of eco-epidemiology for studying the structure and function of natural and anthropogenic foci of infection. Modeling spatial and temporal dynamics can help predict and monitor such tropical diseases.

Enfoques conceptuales y propuestas metodológicas para el estudio de las interacciones entre el medio ambiente y la salud: aplicación a un programa de investigación sobre la tripanosomiasis americana / Conceptual approaches and methodological proposals for the study of interactions between environment and health: application to a research program on American trypanosomiasis

Las modificaciones del paisaje causadas por las actividades y migraciones humanas contribuyen en hacer emerger o re-emerger enfermedades tropicales, particularmente aquellas cuya transmisión se realiza por insectos vectores que a menudo deben escapar a las condiciones cambiantes ambientales, adaptándose y modificando sus redes tróficas, su morfología, hasta su genotipo. Obtener una mejor comprensión de las relaciones entre los factores ecológicos y humanos y las antropozoonosis es vital para poder identificar variables que permitan cartografiar el riesgo para las poblaciones humanas. Este es el objetivo del programa de investigación Ecología del Paisaje, Dinámica de los Agro-Ecosistemas y Complejos Eco-Patógenos: La Definición del Riesgo Eco-Epidemiológico en la Tripanosomiasis Americana que se desarrolla en diferentes ecosistemas del Brasil. Los autores describen las bases conceptuales y metodológicas del programa e insisten sobre el rol del método eco-epidemiológico para el estudio de la estructura y el funcionamiento de los focos naturales y antropizados de la infección. Modelizar su dinámica espacial y temporal permite concebir nuevos útiles de predicción y de vigilancia