Insights from tissue-specific transcriptome sequencing analysis of Triatoma infestans.

Triatoma infestans is an insect of subfamily Triatominae (Hemiptera: Reduviidae) and an important vector of Trypanosoma cruzi, the etiologic agent of human Chagas disease. In this work we reported a transcriptome assembly and annotation of T. infestans heads obtained by Next Generation Sequencing (NGS) technologies.

Ecological host fitting of Trypanosoma cruzi TcI in Bolivia: mosaic population structure, hybridization and a role for humans in Andean parasite dispersal.

An improved understanding of how a parasite species exploits its genetic repertoire to colonize novel hosts and environmental niches is crucial to establish the epidemiological risk associated with emergent pathogenic genotypes. Trypanosoma cruzi, a genetically heterogeneous, multi-host zoonosis, provides an ideal system to examine the sylvatic diversification of parasitic protozoa. In Bolivia, T. cruzi I, the oldest and most widespread genetic lineage, is pervasive across a range of ecological clines. High-resolution nuclear (26 loci) and mitochondrial (10 loci) genotyping of 199 contemporaneous sylvatic TcI clones was undertaken to provide insights into the biogeographical basis of T. cruzi evolution. Three distinct sylvatic parasite transmission cycles were identified: one highland population among terrestrial rodent and triatomine species, composed of genetically homogenous strains (Ar = 2.95; PA/L = 0.61; DAS = 0.151), and two highly diverse, parasite assemblages circulating among predominantly arboreal mammals and vectors in the lowlands (Ar = 3.40 and 3.93; PA/L = 1.12 and 0.60; DAS = 0.425 and 0.311, respectively). Very limited gene flow between neighbouring terrestrial highland and arboreal lowland areas (distance ~220 km; FST = 0.42 and 0.35) but strong connectivity between ecologically similar but geographically disparate terrestrial highland ecotopes (distance >465 km; FST = 0.016-0.084) strongly supports ecological host fitting as the predominant mechanism of parasite diversification. Dissimilar heterozygosity estimates (excess in highlands, deficit in lowlands) and mitochondrial introgression among lowland strains may indicate fundamental differences in mating strategies between populations. Finally, accelerated parasite dissemination between densely populated, highland areas, compared to uninhabited lowland foci, likely reflects passive, long-range anthroponotic dispersal. The impact of humans on the risk of epizootic Chagas disease transmission in Bolivia is discussed.

Sand fly fauna in Chapare, Bolivia: an endemic focus of Leishmania (Viannia) braziliensis.

Data on the distribution and abundance of Lutzomyia spp. (Diptera: Psychodidae) in Bolivia is scarce. Sand flies from an area of Leishmania (Viannia) braziliensis endemicity in the Isiboro-Secure National Park in the Department of Cochabamba were captured and identified to species. In total, 945 sand flies (789 females and 156 males) belonging to 15 species were collected from the four collection points in two study villages in 2007. With 549 (58.1%) specimens, Lutzomyia shawi was the most abundant species, followed by Lutzomyia (Trichophoromyia) sp. (22.2%), Lutzomyia llanosmartinsi (8.3%), Lutzomyia antunesi (4.3%), and Lutzomyia olmeca (2.1%). Abundance and species composition varied between rainy and dry seasons, with 99.3% of all sand flies being collected outdoors. Because of species abundance and confirmed Leishmania infection in previous entomological collections, we believe Lu. shawi is the vector of L. (Viannia) braziliensis in Isiboro-Secure National Park.

Biología reproductiva de dos poblaciones de Triatoma infestans (Hemiptera: Reduviidae) en condiciones de laboratorio / Reproductive biology of two populations of Triatoma infestans (Hemiptera: Reduviidae) under laboratory conditions

Objetivos: en el presente estudio, se documentó la biología reproductiva de dos poblaciones de T. infestans provenientes de los Valles Mesotérmicos Andinos (20 de Octubre) y del Chaco Serrano (Mataral), en condiciones de laboratorio. Métodos: se utilizaron 15 parejas de T. infestans por población (Mataral y 20 de Octubre) y como población control colonias de T. infestans de laboratorio; siendo alimentados en gallinas durante 45 minutos y mantenidos en una cámara climática a 28±3°C, 60±5%. Se calcularon los siguientes parámetros e índices: Fecundidad, Fertilidad, Índice de Ovipostura (IO), Índice de Fertilidad (IF). Resultados: se observó que las cepa de T. infestans de la localidad 20 de Octubre, presentaron mayor número de huevos; fecundidad promedio por día de (1.95±1.5), una fertilidad de 95.6%, (IO) promedio fue de 0.43 y (IF) promedio de 0.9. Análisis estadísticos indicaron que la localidad 20 de Octubre presentó valores significativos entre variables de número de huevos y peso de los triatominos con una relación de R2=0,77 y una correlación de Pearson (p=0,0008). Conclusiones: en condiciones de laboratorio poblaciones diferentes de T. infestans de diferentes regiones de Bolivia presentan patrones de Fecundidad y Fertilidad diferentes; estos datos son de suma importancia para ser considerados por los Programas de Control Vectorial ya que el ciclo biológico de una misma especie vectora puede variar en función al área geográfica, por lo cual es muy importante continuar con estudios que describan y ayuden a comprender la biología de las principales especies vectores en Bolivia.

Objectives: in the present study, we documented the reproductive biology of two populations of T. infestans, from the mesothermic Andean Valleys (20 de Octubre) and the Chaco Serrano (Mataral) in laboratory conditions. Methods: there was used 15 pairs of T. infestans populations (Mataral and 20 de Octubre). The control population was colonies of T. infestans from laboratory. The insects were fed on chickens for 45 minutes and kept in a climate chamber at 28 ± 3 ° C, 60 ± 5%. The following parameters and rates were calculated: Fecundity, Fertility, oviposition index (IO), fertility index (FI). Results: it was observed that the T. infestans strain from 20 de Octubre locality, presented the greatest number of eggs per day, with a daily fecundity average rate of (1.95 ± 1.5), a fertility of 95.6% (IO) averaged 0.43 (IF) average of 0.9. Statistical analysis shown that the 20 de octubre locality, presented significant values between variables of number of eggs and the weight of triatomines with a ratio of R2 = 0.77 and a significant Pearson correlation. Conclusions: under laboratory conditions two different populations of T. infestans coming from different regions of Bolivia, shown different patterns of fecundity and fertility, these data are of valuable importance to be considered by vector control programs, since showed that the life cycle of the same vector species may vary according to geographical area, therefore, is very important to continue with studies that describe and help to understand the biology of the main vector species in Bolivia.