The Role of Domestic Animals in the Small-Scale Ecology of Triatoma infestans, a Vector of Chagas Disease

Animal sentinels;Chagas disease;Ecology;Ecotopes;Dispersion;Triatoma infestans;Epidemiology

Castillo, RicardoGilman, Robert H. ;

Johns Hopkins University

关键词: Animal sentinels;    Chagas disease;    Ecology;    Ecotopes;    Dispersion;    Triatoma infestans;    Epidemiology;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/39294/CASTILLO-DISSERTATION-2014.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

This dissertation investigates the associations between domestic animals and the ecology of Triatoma infestans, a vector of Chagas disease. The ecology of Triatoma infestans in relation to domestic animals has been studied in other areas, but it is context dependent and the approaches might differ. This dissertation combines field observations and experimental data, and uses concepts from epidemiology, entomology, and ecology to understand the interactions between domestic animals, Triatoma infestans and Trypanosoma cruzi, the parasite the causes Chagas disease.The first aim uses a novel approach to analyze the influence of domestic animal species and animal corral construction materials on the presence and abundance of Triatoma infestans. This analysis combines both, domestic animal species and construction materials, to define ecotopes, the smallest ecologically distinct landscape unit. These ecotopes might increase or reduce the odds of finding T. infestans and their abundance. We found that small mammals (guinea pigs and rabbits) living in enclosures built with stacked stones or bricks increases the odds of finding insect vectors and of finding more abundant colonies. Other animal species raised in enclosures built with wire mesh showed a protective effect against harboring insect vectors.The second aim proposes to use dogs as animal sentinels to determine areas of transmission of Trypanosoma cruzi. We analyzed data from a cross sectional entomological survey and a canine serological survey and found a strong spatial association between seropositive dogs and parasite-carrying vector colonies. In addition, increasing age seroprevalence curves and behavioral features of dogs support the hypothesis that dogs can be good animal sentinels for T. cruzi transmission. This section of the dissertation also discusses feasibility of dog sentinels and proposes ways to integrate this approach with current health programs.Finally, the third aim examines the influence of the population dynamics of domestic animals on Triatoma infestans dispersion. We created a laboratory experiment to explore and characterize the host-seeking behavior of T. infestans and its dispersion under the constant presence of hosts and after these hosts are removed. We found that there was an important level of random dispersion in the constant presence of hosts, but population dynamics of hosts had a strong influence on vector dispersion. After host removal, we found spatial patterns of dispersion that suggest that empty animal enclosures remain attractive for vectors, and most importantly, vector activity increased significantly after hosts were removed which might indicate increased risk for humans in infested areas where animal populations fluctuate.