Browsing by Autor "Lori Stevens"

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A method for the identification of guinea pig blood meal in the Chagas disease vector, Triatoma infestans
(Springer Science+Business Media, 2007) J.C. Pizarro; David E. Lucero; Lori Stevens
A New Method for Forensic DNA Analysis of the Blood Meal in Chagas Disease Vectors Demonstrated Using Triatoma infestans from Chuquisaca, Bolivia
(Public Library of Science, 2008) J.C. Pizarro; Lori Stevens
The results of the assays revealed that a high percentage of insects collected in human dwellings had fed on peri-domestic animals. In contrast, one insect from a chicken coop but no bugs from corrals tested positive for human blood. Forty-eight percent of insects tested positive for more than one vertebrate species. T. cruzi infection was detected in 42% of the specimens. From the epidemiological point of view, the results reveal an overall pattern of movement from peri-domestic structures to human habitations for T. infestans in this region of Bolivia as well as the important role of pigs, dogs, chickens and guinea pigs in the dynamics of T. cruzi infection.
Genetic diversity of Triatoma infestans (Hemiptera: Reduviidae) in Chuquisaca, Bolivia based on the mitochondrial cytochrome b gene
(Instituto Oswaldo Cruz, Ministério da Saúde, 2005) Rosanna Giordano; Juan Carlos Pizarro Cortez; Stephanie Paulk; Lori Stevens
Partial cytochrome b DNA sequences for 62 Triatoma infestans were analyzed to determine the degree of genetic variation present in populations of this insect in the northwest region of Chuquisaca, Bolivia. A total of seven haplotypes were detected in the localities sampled. The phylogenetic relationship and population genetic structure of the haplotypes found in this region, indicate that there is greater variation in this relatively small region of Bolivia than what has been previously reported by studies using the same gene fragment, for more distant geographic areas of this country. In addition, a comparison of rural and peri-urban localities, indicate that there is no difference in the genetic variation of T. infestans between these two environments.
Microsatellites Reveal a High Population Structure in Triatoma infestans from Chuquisaca, Bolivia
(Public Library of Science, 2008) J.C. Pizarro; Lauren M. Gilligan; Lori Stevens
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.
PCR reveals significantly higher rates of Trypanosoma cruzi infection than microscopy in the Chagas vector, Triatoma infestans: High rates found in Chuquisaca, Bolivia
(BioMed Central, 2007) J.C. Pizarro; David E. Lucero; Lori Stevens
Sources of Blood Meals of Sylvatic Triatoma guasayana near Zurima, Bolivia, Assayed with qPCR and 12S Cloning
(Public Library of Science, 2014) David E. Lucero; Wilma Ribera; J.C. Pizarro; Plaza Carlos; Levi W. Gordon; Reynaldo Peña; L. A. Morrissey; Donna M. Rizzo; Lori Stevens
We show that cloning of 12S PCR products, which avoids bias associated with developing primers based on a priori knowledge, detected blood meal sources not previously considered and that species-specific qPCR is more sensitive. All samples identified as positive for a specific blood meal source by the cloning assay were also positive by qPCR. However, not all samples positive by qPCR were positive by cloning. We show the power of combining the cloning assay with the highly sensitive hydrolysis probe-based qPCR assay provides a more complete picture of blood meal sources for insect disease vectors.