Browsing by Autor "Etienne Waleckx"

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“Andean” and “non-Andean” ITS-2 and mtCytB haplotypes of Triatoma infestans are observed in the Gran Chaco (Bolivia): Population genetics and the origin of reinfestation
(Elsevier BV, 2011) Sergio Quisberth; Etienne Waleckx; Marcelo Monje; Boris Chang; François Noireau; Simone Frédérique Brénière
Combination of cytochrome b heteroduplex-assay and sequencing for identification of triatomine blood meals
(Elsevier BV, 2011) Rosio Buitrago; Stéphanie Depickère; Marie-France Bosseno; Edda Siñani Patzi; Etienne Waleckx; Renata Salas; Claudia Aliaga; Simone Frédérique Brénière
Extreme inbreeding in <i>Leishmania braziliensis</i>
(National Academy of Sciences, 2009) Virginie Rougeron; Thierry De Meeûs; Mallorie Hidé; Etienne Waleckx; Herman Bermudez; Jorge Arévalo; Alejandro Llanos‐Cuentas; J.-C. Dujardin; Simone De Doncker; Dominique Le Ray
Leishmania species of the subgenus Viannia and especially Leishmania braziliensis are responsible for a large proportion of New World leishmaniasis cases. The reproductive mode of Leishmania species has often been assumed to be predominantly clonal, but remains unsettled. We have investigated the genetic polymorphism at 12 microsatellite loci on 124 human strains of Leishmania braziliensis from 2 countries, Peru and Bolivia. There is substantial genetic diversity, with an average of 12.4 +/- 4.4 alleles per locus. There is linkage disequilibrium at a genome-wide scale, as well as a substantial heterozygote deficit (more than 50% the expected value from Hardy-Weinberg equilibrium), which indicates high levels of inbreeding. These observations are inconsistent with a strictly clonal model of reproduction, which implies excess heterozygosity. Moreover, there is large genetic heterogeneity between populations within countries (Wahlund effect), which evinces a strong population structure at a microgeographic scale. Our findings are compatible with the existence of population foci at a microgeographic scale, where clonality alternates with sexuality of an endogamic nature, with possible occasional recombination events between individuals of different genotypes. These findings provide key clues on the ecology and transmission patterns of Leishmania parasites.
First Report of Widespread Wild Populations of Triatoma infestans (Reduviidae, Triatominae) in the Valleys of La Paz, Bolivia
(American Society of Tropical Medicine and Hygiene, 2010) Rosio Buitrago; Pablo Vidaurre; Faustine Zovéda; Simone Frédérique Brénière; Etienne Waleckx; Renata Salas; Marie-France Bosseno; François Noireau; Elio Mamani
Wild populations of Triatoma infestans, the main vector of Chagas disease in the Southern Cone countries, may be involved in reinfestation of human dwellings, limiting the success of vector-control campaigns in Bolivia. Knowledge of the distribution of these populations remains incomplete. We report here the detection of T. infestans wild populations in large areas in the department of La Paz, Bolivia. Among 18 sylvatic areas investigated, 17 were positive with T. infestans specimens. The infection rate of captured T. infestans with Trypanosoma cruzi was 85.7% in adult specimens. These results expand the geographical distribution of wild populations of T. infestans; it may be distributed throughout the Inter-Andean Dry Forest eco-region of Bolivia. The current information allows us to propose the hypothesis that a sylvatic origin of the reinfestation is located in the valleys of La Paz.
Genetic Characterization of Trypanosoma cruzi DTUs in Wild Triatoma infestans from Bolivia: Predominance of TcI
(Public Library of Science, 2012) Simone Frédérique Brénière; Claudia Aliaga; Etienne Waleckx; Rosio Buitrago; Renata Salas; Christian Barnabé; Michel Tibayrenc; François Noireau
By exploring large-scale DTUs that infect the wild populations of T. infestans, this study opens the discussion on the origin of TcI and TcV DTUs that are predominant in domestic Bolivian cycles.
New Discoveries of Sylvatic Triatoma infestans (Hemiptera: Reduviidae) Throughout the Bolivian Chaco
(American Society of Tropical Medicine and Hygiene, 2012) Etienne Waleckx; Stéphanie Depickère; Renata Salas; Claudia Aliaga; Marcelo Monje; Hiber Calle; Rosio Buitrago; François Noireau; Simone Frédérique Brénière
Sylvatic populations of Triatoma infestans might be involved in the recolonization of human dwellings. We report here the discoveries of new T. infestans sylvatic foci in the Bolivian Chaco. Eighty-one triatomines were caught, 38 of which were identified as T. infestans. Triatoma sordida and Panstrongylus geniculatus were the other species collected. One T. infestans and one T. sordida were infected with Trypanosoma cruzi TcI; one T. infestans was infected with TcII. These discoveries add to the debate on the geographic distribution of sylvatic T. infestans populations, the geographic origin of the species, and the epidemiological role of these populations.
New insights on the Chagas disease main vector Triatoma infestans (Reduviidae, Triatominae) brought by the genetic analysis of Bolivian sylvatic populations
(Elsevier BV, 2011) Etienne Waleckx; Renata Salas; Nerida Huamán; Rosio Buitrago; Marie-France Bosseno; Claudia Aliaga; Christian Barnabé; Roberto Rodríguez; Faustine Zovéda; Marcelo Monje
Population genetic structure of Meccus longipennis (Hemiptera, Reduviidae, Triatominae), vector of Chagas disease in West Mexico
(Elsevier BV, 2011) Simone Frédérique Brénière; Etienne Waleckx; Ezequiel Magallón-Gastélum; Marie-France Bosseno; Xavier Hardy; Cyrille Ndo; Felipe Lozano-Kasten; Christian Barnabé; Pierre Kengne
Risk of transmission of Trypanosoma cruzi by wild Triatoma infestans (Hemiptera: Reduviidae) in Bolivia supported by the detection of human blood meals
(Elsevier BV, 2013) Nelly Lilian Rosio Buitrago; Marie France Bosseno; Etienne Waleckx; Philippe Brémond; Pablo Vidaurre; Faustine Zovéda; Simone Frédérique Brénière
Susceptibility and resistance to deltamethrin of wild and domestic populations of Triatoma infestans (Reduviidae: Triatominae) in Bolivia: new discoveries
(Instituto Oswaldo Cruz, Ministério da Saúde, 2012) Stéphanie Depickère; Rosio Buitrago; Edda Siñani; Marianne Baune; Marcelo Monje; Ronald López; Etienne Waleckx; Tamara Chávez; Simone Frédérique Brénière
Bolivia is a high-endemic country for Chagas disease, for which the principal vector is Triatoma infestans (Triatominae). This is a mainly domestic species that is also found in the wild environment. Recently, an increasing number of studies have shown the importance of Triatominae resistance to insecticides, especially in Bolivia. Data regarding the susceptibility/resistance of wild and domestic populations of T. infestans to deltamethrin are presented. For the first time, domestic populations of the department of Santa Cruz were tested, showing low resistance. Although most of the wild populations were found to be susceptible to deltamethrin, three populations from three departments showed a mortality rate of less than 100%. This result is emphasised here.
Wild populations of Triatoma infestans : Compilation of positive sites and comparison of their ecological niche with domestic population niche
(Elsevier BV, 2017) Simone Frédérique Brénière; Rosio Buitrago; Etienne Waleckx; Stéphanie Depickère; Victor Sosa; Christian Barnabé; David E. Gorla
Wild Populations of Triatoma infestans Are Highly Connected to Intra-Peridomestic Conspecific Populations in the Bolivian Andes
(Public Library of Science, 2013) Simone Frédérique Brénière; Renata Salas; Rosio Buitrago; Philippe Brémond; Victor Sosa; Marie-France Bosseno; Etienne Waleckx; Stéphanie Depickère; Christian Barnabé
Triatoma infestans, the major vector of Chagas disease south of the Amazon in South America, has a large distribution of wild populations, contrary to what has previously been stated. These populations have been suspected of being the source of reinfestation of human habitats and could impede the full success of vector control campaigns. This study examined gene flow between intra-peridomestic populations and wild populations collected in the surround areas in three Andean localities in Bolivia. The populations were defined according to temporal, ecological, and spatial criteria. After DNA extraction from the legs of each insect, the samples were analyzed using seven microsatellite markers. First, the analysis of molecular variance (AMOVA) detected an absence of differentiation between wild and intra-peridomestic populations, although strong structuring was observed between the populations within each environment. Then for some populations, the Bayesian method of assignment to inferred populations showed very similar assignment patterns of the members of wild or intra-peridomestic populations in each locality. Finally, the detection of the first-generation migrants within the different populations provided evidence of insect displacement from the wild to the intra-peridomestic environment. This result indicates that, after control campaigns in the Andes, controlling this new paradigm of vector transmission risk stemming from the invasion of human habitats by wild populations of T. infestans requires long-term maintenance of public monitoring to keep the risk at a minimal level. Since wild populations of T. infestans have also been detected elsewhere in Argentina, Paraguay, and Chile, there is an urgent need to take these populations into account in future monitoring of Chagas disease transmission.