Dataset Information

Microsatellites reveal a high population structure in Triatoma infestans from Chuquisaca, Bolivia.

ABSTRACT:

Background

For Chagas disease, the most serious infectious disease in the Americas, effective disease control depends on elimination of vectors through spraying with insecticides. Molecular genetic research can help vector control programs by identifying and characterizing vector populations and then developing effective intervention strategies.

Methods and findings

The population genetic structure of Triatoma infestans (Hemiptera: Reduviidae), the main vector of Chagas disease in Bolivia, was investigated using a hierarchical sampling strategy. A total of 230 adults and nymphs from 23 localities throughout the department of Chuquisaca in Southern Bolivia were analyzed at ten microsatellite loci. Population structure, estimated using analysis of molecular variance (AMOVA) to estimate F(ST) (infinite alleles model) and R(ST) (stepwise mutation model), was significant between western and eastern regions within Chuquisaca and between insects collected in domestic and peri-domestic habitats. Genetic differentiation at three different hierarchical geographic levels was significant, even in the case of adjacent households within a single locality (R(ST) = 0.14, F(ST) = 0.07). On the largest geographic scale, among five communities up to 100 km apart, R(ST) = 0.12 and F(ST) = 0.06. Cluster analysis combined with assignment tests identified five clusters within the five communities.

Conclusions

Some houses are colonized by insects from several genetic clusters after spraying, whereas other households are colonized predominately by insects from a single cluster. Significant population structure, measured by both R(ST) and F(ST), supports the hypothesis of poor dispersal ability and/or reduced migration of T. infestans. The high degree of genetic structure at small geographic scales, inferences from cluster analysis and assignment tests, and demographic data suggest reinfesting vectors are coming from nearby and from recrudescence (hatching of eggs that were laid before insecticide spraying). Suggestions for using these results in vector control strategies are made.

SUBMITTER: Pizarro JC

PROVIDER: S-EPMC2268005 | biostudies-literature | 2008 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Microsatellites reveal a high population structure in Triatoma infestans from Chuquisaca, Bolivia.

Pizarro Juan Carlos JC Gilligan Lauren M LM Stevens Lori L

PLoS neglected tropical diseases 20080326 3

<h4>Background</h4>For Chagas disease, the most serious infectious disease in the Americas, effective disease control depends on elimination of vectors through spraying with insecticides. Molecular genetic research can help vector control programs by identifying and characterizing vector populations and then developing effective intervention strategies.<h4>Methods and findings</h4>The population genetic structure of Triatoma infestans (Hemiptera: Reduviidae), the main vector of Chagas disease in ...[more]

PMID: 18365033

Similar Datasets

Project description:Sylvatic populations of Triatoma infestans represent a challenge to Chagas disease control as they are not targeted by vector control activities and may play a key role in post-spraying house re-infestation. Understanding sylvatic foci distribution and gene flow between sylvatic and domestic populations is crucial to optimize vector control interventions and elucidate the development and spread of insecticide resistance. Herein, the genetic profiles of five Andean T. infestans populations from Bolivia with distinct insecticide susceptibility profiles were compared. Multilocus genotypes based on eight microsatellites and the DNA sequence of a fragment of the cytochrome B (cytB) gene were obtained for 92 individuals. CytB haplotypes were analyzed with previously reported Bolivian T. infestans haplotypes to evaluate putative historical gene flow among populations. Each specimen was also screened for two nucleotide mutations in the sodium channel gene (kdr), related to pyrethroid resistance (L1014 and L9251). Significant genetic differentiation was observed among all populations, although individuals of admixed origin were detected in four of them. Notably, the genetic profiles of adjacent domestic and sylvatic populations of Mataral, characterized by higher levels of insecticide resistance, support their common ancestry. Only one sylvatic individual from Mataral carried the kdr mutation L1014, suggesting that this mechanism is unlikely to cause the altered insecticide susceptibility observed in these populations. However, as the resistance mutation is present in the area, it has the potential to be selected under insecticidal pressure. Genetic comparisons of these populations suggest that insecticide resistance is likely conferred by ancient trait(s) in T. infestans sylvatic populations, which are capable of invading domiciles. These results emphasize the need for stronger entomological surveillance in the region, including early detection of house invasion, particularly post-spraying, monitoring for resistance to pyrethroids and the design of integrative control actions that consider sylvatic foci around domestic settings and their dispersion dynamics.

Dataset Information

Microsatellites reveal a high population structure in Triatoma infestans from Chuquisaca, Bolivia.

Background

Methods and findings

Conclusions

Publications

Microsatellites reveal a high population structure in Triatoma infestans from Chuquisaca, Bolivia.

Similar Datasets

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