The kissing bug, Triatoma infestans, the principal vector of Chagas disease, has recently dispersed through the Peruvian city of Arequipa. The biological invasion of this insect has resulted in a public health crisis, putting thousands of residents of this city at risk of infection by Trypanosoma cruzi and subsequent development of Chagas disease. In this work we include population genetic analyses at three different scales ranging from large continental scale to the very fine, neighborhood scale. We show through analyses with publically available sequence data, that the likely origin of the T. infestans population in Arequipa is the Andean region of Bolivia or northern Chile. Extremely low genetic diversity is characteristic of a founding event either after the initial colonization or in the source population (or few migrants). Populations of T. infestans in geographically distinct districts within and around Arequipa share a common recent evolutionary history although current gene flow is restricted even between proximal sites. The population structure among the T. infestans in different districts is not correlated with the geographic distance between districts. These data suggest that migration among the districts is mediated by factors beyond the short-range migratory capabilities of T. infestans and that human movement has played a significant role in the structuring of the T. infestans population in the region. Within one of the districts along a 1.5 km transect, we show the movement of T. infestans is constrained by the spatial structuring of the built environment. City blocks have a clear effect on dispersal---samples collected on the same block are more similar than those collected on different blocks at comparable distances. The urban grid significantly impacts population genetic structure and dispersal through the human constructed environment. Rapid urbanization across southern South America will continue to create suitable environments for T. infestans such that knowledge of its urban dispersal patterns may play a fundamental role in mitigating human disease risk.
Thesis (Ph.D. in Biology) -- University of Pennsylvania, 2013. Source: Dissertation Abstracts International, Volume: 74-10(E), Section: B. Adviser: Dustin Brisson.