Browsing by Autor "Noireau, François"

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Biología reproductiva de dos poblaciones de Triatoma infestans (Hemiptera: Reduviidae) en condiciones de laboratorio
(Gac Med Bol, 2011) Espinoza, Jorge; Bustamante, Marinely; García, Ana Lineth; Tenorio, Omar; Noireau, François; Rivera, Demetrio; Rojas Cortez, Mirko
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.
Current spread of Triatoma infestans at the expense of Triatoma sordida in Bolivia
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1996) Noireau, François
Triatoma infestans is the most widespread synanthropic species of Triatominae and the most important vector of Chagas disease in South America. The progressive geographical expansion of this species from its silvatic focus of origin in the Cochabamba valley of Bolivia (JP Dujardin et al. 1987 J Med Entomol 24: 40-45) was probably associated with human migration into the continent (CJ Schofield 1988 Biosystematics of haematophagous insects, p. 285-312. MW Service Oxford). Triatoma sordida, a species associated with silvatic and peridomestic habitats, is currently found in houses in some rural areas of Bolivia, particularly in La Paz and Santa Cruz departments (E De Muynck 1977 Bol Inform CENETROP 3: 41-51, F Noireau et al. 1995 J Med Entomol 32: 594-598). The analysis of the present distribution of T. sordida in Bolivia, in comparison to 20 years ago data, gives a clear indication of the reduction of the area within which this species is found in houses and its substitution by T. infestans, the most important vector of Chagas disease in this country.
Detection of sylvatic dark morphs of Triatoma infestans in the Bolivian Chaco
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1997) Noireau, François
Triatoma infestans, the most important vector of Chagas disease in the southern part of Latin America, is considered to originate from the Cochabamba valley in Bolivia because this is the only region where true sylvatic foci have been confirmed (RA Torrico 1946 An Lab Central Cochabamba 1: 19-23. JP Dujardin et al. 1987 J Med Entomol 24: 40-45, H Bermudez et al. 1993 Am J Trop Med Hyg 49 suppl.: 371). Genetic arguments fully support this assumption (JPDujardin et al. 1997 Med Vet Entomol, in press). Except for this region where sylvatic colonies of T. infestans were found amongst rock-piles associated with wild guinea-pigs (Galea musteloides), T. infestans is said to be confined to domestic and peridomestic habitats throughout its distribution area (RL Usinger et al. 1966 an Rev Entomol 11: 309-330, CJ Schofield 1988 Biosystematics of Haematophagous Insects ed. MW Service 37: 284-312, Clarendon Press, Oxford).
Genetic structure of Triatoma sordida (Hemiptera: Reduviidae) domestic populations from Bolivia : application on control interventions
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1999) Noireau, François
The genetic population of Triatoma sordida group 1, a secondary vector of Chagas disease in Bolivia, was studied by multi-locus enzyme electrophoresis. A total of 253 nymphal and adult specimens collected from seven neighbouring localities in the Velasco Province, Department of Santa Cruz, were processed. The relatively low genetic variability was confirmed for this species (rate of polymorphism: 0.20). The absence of genetic disequilibrium detected within the seven localities was demonstrated. A geographical structuration appears between localities with distances greater than 20 km apart. Although T. sordida presents a relatively reduced dispersive capacity, its panmictic unit is wider than compared with T. infestans. Genetic distances between T. sordida populations were correlated with geographic distance. Gene flow between geographic populations of T. sordida provides an efficient framework for effective vigilance and control protocols.
Sylvatic triatomines (Hemiptera: Reduviidae) in Bolivia : trends toward domesticity and possibleinfection with Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae)
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1995) Noireau, François
ABSTRACT The risk of domestic transmission of Trypanosoma cruzi (Chagas) by sylvatic triatomines was assessed in an isolated area of the subandean region of Bolivia. None of the 390 residents examined had serological evidence of infection. Two sylvatic triatomine species, Eratyrus mucronatus (Stal) and Triatoma sordida (Stal), were found in houses and in peridomestic structures. The collection of nymphal instars of both species from some houses indicated possible domesticity. Microscopic examination of feces from 92 insects showed no parasites, and cultures from the guts of 30 insects were negative. Nevertheless, a polymerase chain reaction (PCR) test performed on the same fecal samples showed the presence of T. cruzi DNA in 19.1 and 12.5% of E. mucronatus and T. sordida, respectively. These 16 PCR positive samples were hybridized with 2 T. cruzi-specific probes known from the domestic cycle in Bolivia (clones 20 and 39). At least 1 of these clones was identified in 7 bugs (5 E. mucronatus and 2 T sordida). Moreover, no hybridization was observed with these probes in 8 E. mucronatus and 1 T sordida samples that showed an amplified band by PCR. These data indicated that T. cruzi clones, genetically unrelated to clones 20 and 39, also were circulating in this area. Based on these results, the 2 sylvatic triatomine species encountered in Apolo should not be overlooked as possible local vectors of T cruzi.