Demographic inferences using population genetics: Triatoma rubida, vector of chagas disease along the west Texas-Mexico border

Background/Question/Methods Until recently, little attention has been given to kissing bugs in the United States, since Chagas disease it is not usually reported as acquired in the country. The kissing bug Triatoma rubida (Hemiptera: Reduviidae) is commonly found along the West Texas-Mexico border area and it is a competent vector of Trypanosoma cruzi, the etiological agent of the Chagas disease. Recent studies have shown that the parasite is highly prevalent among kissing bugs and vertebrates in this region. In recent years, the region experienced major alterations to the environment due to anthropogenic activities such as habitat degradation, fragmentation, and creation of novel urban environments. The objective of the present study is to assess the demography and genetic structure of Triatoma rubida in the area. The collected samples included individuals from an isolated rural location and various locations associated with different degrees of urbanization and changes in the land use. We extracted DNA from the samples and sequenced both mitochondrial and nuclear loci in order to calculate genetic indexes, demographic estimators, and population dynamics among sampled locations.

Results/Conclusions Our results suggest a high level of differentiation between the sampled locations, including marked differences in the estimation of demographic parameters. The analyses identified two clades, the first one associated with locations characterized as more rural while the second one is associated with locations more urbanized. Interestingly, the clade associated with urban areas has lower genetic diversity and appears to have lower estimations of effective population size and rate of growth compared with the second clade. The differences can be related with changes in land use and urbanization among the different locations sampled. These analyses are critical to understanding if changes in the vector population dynamics are related with human-driven changes on the environment. Changes in the vector population can influence the prevalence of the disease that they transmit, and consequently, the risk for human and domestic animal populations living in the immediate area.