Home Economics American Trypanosomiasis Chagas Disease, Second Edition: One Hundred Years of Research
Vector population structure directs Chagas disease epidemiology and control
A central tenant of population genetics is a hypothetical population with random genetic variation; that is, variation in alleles are randomly distributed with respect to space, time, ecological conditions, or any other factor. Ecological and evolutionary processes result in deviations from a random distribution. A textbook definition of population is a collection of interbreeding organisms of a particular species, but in practical terms populations are usually defined according to operational criteria (e.g., geographic proximity, sample availability, or even geopolitical limits). Genetic variation can be observed over multiple spatial and temporal scales, for example, within individuals as heterozygosity, within populations as deviations from HWE, and as genetic distance between populations. Human Chagas infection is endemic throughout Latin America, where its associated burden is larger than the combined burden of malaria, leprosy, leishmaniasis, filariasis, schistosomiasis, dengue, and the major intestinal nematode infections.11 Although the etiological agent, Trypanosoma cruzi, is most often transmitted by insect vectors, recently Chagas is a concern in nonendemic areas, including the United States and Europe, due to immigration of infected individuals act as blood or organ donors or transmit the parasite congenitally.
There is no vaccine against T. cruzi, and the troublesome side effects of the medications make large-scale disease treatment difficult. As a consequence, disease control relies heavily on the elimination of domestic vector populations by house improvements combined with the spraying of residual insecticides and serological screening of blood donations. The importance of vector transmission results in a constant need for the development and optimization of vector control strategies to keep pace with the ever-changing epidemiological scenarios.12 This is why furthering knowledge of triatomine population structure and gene flow, along with detection of cryptic (morphologically similar but genetically different) taxa that could exhibit different vectorial capabilities is so important.
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