Browsing by Autor "JP Dujardin"

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Chagas disease vector control in Central America
(Elsevier BV, 1997) CJ Schofield; JP Dujardin
Changes in the Sexual Dimorphism of Triatominae in the Transition from Natural to Artificial Habitats
(Instituto Oswaldo Cruz, Ministério da Saúde, 1999) JP Dujardin; Mário Steindel; T. Chavez; M. Machane; CJ Schofield
A shift from large to small average sizes was observed in Triatoma infestans and Rhodnius domesticus between field and domestic (or laboratory) conditions of life. It was more pronounced in the female specimens, leading to a subsequent reduction of sexual size dimorphism. This feature is discussed in terms of genetic and populational changes occurring from natural to artificial habitats, in particular those related to population densities. Sexual size dimorphism is then recommended as a new character to be used in the study of species of Triatominae adapting to domestic ecotopes.
Domiciliation process of Rhodnius stali (Hemiptera: Reduviidae) in Alto Beni, La Paz, Bolivia
(Wiley, 2003) A. Matias; J De la Riva; E. Martínez; M. Torrez; JP Dujardin
We report a systematic collection of Triatominae inside houses and in the peridomestic environment of Alto Beni, department of La Paz, Bolivia. This area is free of Triatoma infestans and although we detected previously seropositivity for Trypanosoma cruzi, the Alto Beni region is not officially considered as endemic for Chagas disease. From 11 houses of five localities, we collected adults, nymphs and eggs of a Rhodnius species, which was confirmed by morphological and morphometric analysis as Rhodnius stali. This little-known species has long been confused with R. pictipes, and was originally described from museum specimens labelled as R. pictipes. Our data show that R. stali is able to establish colonies in domestic and peridomestic habitats in Bolivia, and it is probably the vector responsible for Chagas disease seropositivity observed in the indigenous population of Alto Beni.
Geographical versus interspecific differentiation of sand flies (Diptera: Psychodidae): a landmark data analysis
(Cambridge University Press, 2003) JP Dujardin; François Le Pont; Michel Baylac
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IsLutzomyia serrana(Diptera, Psychodidae, Phlebotominae) present in Ecuador ?
(EDP Sciences, 2004) JP Dujardin; François Le Pont; E. Maritnez
We describe a multivariate metric comparison of three sandfly species showing strong differences in size, which questions the geographical distribution of one of them. Two species are represented by a single population (L. robusta and L. guilvardae) and one by two populations (L. serrana). All of them belong to the series serrana (Diptera, Psychodidae, Phlebotominae). The morphometric data confirm that L. guilvardae is a distinct species. However, they suggest that L. robusta and L. serrana in Ecuador are the same taxon, and that it is distinguishable from the population of L. serrana in Bolivia. A multilocus enzyme electrophoresis analysis comparing L. serrana in Bolivia and L. robusta in Ecuador adds further evidence that these two populations are distinct species. Thus, our data seem to indicate that, in Ecuador, the population previously identified as L. serrana is actually the same species as the allopatric population previously identified as L. robusta. Accepting L. serrana in Ecuador as small-sized L. robusta, the resulting geographic distribution of this latter becomes in closer agreement with ecology and epidemiology.
Isoenzyme electrophoresis of Rhodnius species: a phenetic approach to relationships within the genus
(Maney Publishing, 1999) T. Chavez; J. Moreno; JP Dujardin
AbstractSeventeen samples of Rhodnius, representing at least eight different species according to their morphological characteristics, were submitted to multilocus isoenzyme electrophoresis, revealing 17 different loci. A phenetic analysis of the enzyme data not only clustered the species in accordance with their geographical origin but also revealed interspecific relationships that differed from those expected from the morphology.
Lutzomyia nuneztovari anglesi (Le pont & Desjeux, 1984) as a vector of Leishmania amazonensis in a sub-Andean leishmaniasis focus of Bolivia.
(American Society of Tropical Medicine and Hygiene, 1999) E. Martínez; François Le Pont; M Torrez; Jenny Telleria; Fernando Regla Vargas; Jean-Pierre Dujardin; JP Dujardin
Recently, a new Leishmania amazonensis focus was described in a sub-Andean region (1,450-2,100 meters above sea level) of Bolivia. In this area, three anthropophilic sandfly species were identified: Lutzomyia nuneztovari anglesi Le Pont & Desjeux, 1984, which represented 86-99% of the captures, Lu. galatiae Le Pont et al., 1998, and Lu. shannoni Dyar 1929. Only Lu. nuneztovari anglesi was found naturally infected by flagellates (16 of 1,715 females). Three Leishmania stocks were isolated and analyzed by isoenzyme electrophoresis at 11 loci. No significant isoenzymatic differences were demonstrated between them and 7 stocks isolated from patients from the same area, and previously characterized as L. amazonensis. Moreover, in a simplified protocol, the experimental infection of Lu. nuneztovari anglesi by L. amazonensis was successful in 92% of the surviving specimens. These data are discussed in relation to the Killick-Kendrick criteria. These results strongly suggest that Lu. nuneztovari anglesi is the vector of L amazonensis at Cajuata, Inquisivi, La Paz, Bolivia.
Malaria: Growth and Selection
(Elsevier BV, 1999) C.J. Schofield; JP Dujardin
Morphometrics of domestic Panstrongylus rufotuberculatus in Bolivia
(Maney Publishing, 1998) JP Dujardin; G. Forgues; M. Torrez; E. Martínez; C. Cordoba; Alberto Gianella
The trend to domesticity in Triatominae may represent a transitionary phase towards increasing vectorial importance in the transmission of Chagas disease to humans, and requires sustained entomological surveillance. Although generally considered a sylvatic species, Panstrongylus rufotuberculatus has been recently captured inside human dwellings in the provinces of Nor Yungas and Muñecas in the Department of La Paz, Bolivia, providing evidence of this species' ability to colonise domestic habitats. The results of previous research on domestic and sylvatic specimens of other species of Triatominae indicate that morphometries could be used to monitor this adaptive process. The most likely cause of differences seen in the size and shape of bugs from domestic colonies of P. rufotuberculatus from two neighbouring villages in Bolivia is probably genetic drift rather than environmental influences. Comparison with allopatric sylvatic specimens, including the holotype of P. rufotuberculatus, showed a general reduction in size from sylvatic to domestic specimens.
Quantitative morphological evidence for incipient species within Lutzomyia quinquefer (Diptera: Psychodidae)
(Instituto Oswaldo Cruz, Ministério da Saúde, 1999) JP Dujardin; François Le Pont; E. Martínez
Morphological variation among geographic populations of the New World sand fly Lutzomyia quinquefer (Diptera, Phlebotominae) was analyzed and patterns detected that are probably associated with species emergence. This was achieved by examining the relationships of size and shape components of morphological attributes, and their correlation with geographic parameters. Quantitative and qualitative morphological characters are described, showing in both sexes differences among local populations from four Departments of Bolivia. Four arguments are then developed to reject the hypothesis of environment as the unique source of morphological variation: (1) the persistence of differences after removing the allometric consequences of size variation, (2) the association of local metric properties with meristic and qualitative attributes, rather than with altitude, (3) the positive and significant correlation between metric and geographic distances, and (4) the absence of a significant correlation between altitude and general-size of the insects.
Quantitative phenetics and taxonomy of some phlebotomine taxa
(Instituto Oswaldo Cruz, Ministério da Saúde, 1999) JP Dujardin; François Le Pont; E. Martínez
Elucidating the evolution of Phlebotominae is important not only to revise their taxonomy, but also to help understand the origin of the genus Leishmania and its relationship with humans. Our study is a phenetic portrayal of this history based on the genetic relationships among some New Word and Old Word taxa. We used both multilocus enzyme electrophoresis and morphometry on 24 male specimens of the Old Word genus Phlebotomus (with three of its subgenera: Phlebotomus, Spelaeophlebotomus and Australophlebotomus), and on 67 male specimens of the three New World genera, Warileya, Brumptomyia and Lutzomyia, (with three subgenera of Lutzomyia: Lutzomyia, Oligodontomyia and Psychodopygus). Phenetic trees derived from both techniques were similar, but disclosed relationships that disagree with the present classification of sand flies. The need for a true evolutionary approach is stressed.
Rhodnius robustus in Bolivia identified by its wings
(Instituto Oswaldo Cruz, Ministério da Saúde, 2001) A. Matias; J De la Riva; M. Torrez; JP Dujardin
Wings of a Rhodnius specimen from Alto Beni (Bolivia) was examined for identification and compared with R. stali, R. robustus, (certified Bolivian species), R. pictipes and R. prolixus (suspected Bolivian species). A projection of the unidentified wings as supplementary data into a discriminant analysis of shape revealed clear cut differences with R. stali and R. pictipes, less differences with R. prolixus, and none with R. robustus. Combining global size and shape of the wings, the unknown specimen was identified as R. robustus. Thus, this study confirmed the presence of R. robustus in Bolivia. It also highlighted the possibility of morphometrics to taxonomically interpret one individual, or even one piece of an individual, when related species data are available for comparison.
The process of domestication in triatominae
(Instituto Oswaldo Cruz, Ministério da Saúde, 1999) CJ Schofield; Liléia Diotaiuti; JP Dujardin
Wing geometry as a tool for studying the Lutzomyia longipalpis (Diptera: Psychodidae) complex
(Instituto Oswaldo Cruz, Ministério da Saúde, 2001) J De la Riva; François Le Pont; Viterman Ali; A. Matias; S. Mollinedo; JP Dujardin
Toro Toro (T) and Yungas (Y) have been described as genetically well differentiated populations of the Lutzomyia longipalpis (Lutz & Neiva, 1912) complex in Bolivia. Here we use geometric morphometrics to compare samples from these populations and new populations (Bolivia and Nicaragua), representing distant geographical origins, qualitative morphological variation ("one-spot" or "two-spots" phenotypes), ecologically distinct traits (peridomestic and silvatic populations), and possibly different epidemiological roles (transmitting or nor transmitting Leishmania chagasi). The Nicaragua (N) (Somotillo) sample was "one-spot" phenotype and a possible peridomestic vector. The Bolivian sample of the Y was also "one-spot" phenotype and a demonstrated peridomestic vector of visceral leishmaniasis (VL). The three remaining samples were silvatic, "two-spots" phenotypes. Two of them (Uyuni and T) were collected in the highlands of Bolivian where VL never has been reported. The last one (Robore, R) came from the lowlands of Bolivia, where human cases of VL are sporadically reported. The decomposition of metric variation into size and shape by geometric morphometric techniques suggests the existence of two groups (N/Y/R, and U/T). Several arguments indicate that such subdivision of Lu. longipalpis could correspond to different evolutionary units.