Browsing by Autor "Libia Torrez"

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Anopheles of Bolivia: new records with an updated and annotated checklist
(Elsevier BV, 2008) Frédéric Lardeux; Tamara Chávez; Roberto Rodríguez; Libia Torrez
Anopheles squamifemur has been identified from CDC light trap collections carried out at Arca de Israel, a small community located in the extreme north-east of Bolivia (Pando Department) on the banks of the river Madera, on the border with Brazil. Anopheles costai and An. forattinii have been identified in place of An. mediopunctatus which has been removed from the Bolivian list of Anopheles species. The first identification of An. trinkae in Bolivia by Dr. J.C. Lien in 1984 is cleared. The presence of An. deaneorum in Bolivia has been confirmed by our mosquito captures carried out in Guayaramerín (Pando Department, north-east of Bolivia), a border city separated from the type locality of An. deaneorum, the Brasilian city of Guajara-Mirin, by the large Mamoré River. These new findings increase to 43 the total number of known Anopheles species for Bolivia for which an updated and partially annotated checklist is given.
Comparison of transmission parameters between Anopheles argyritarsis and Anopheles pseudopunctipennis in two ecologically different localities of Bolivia
(BioMed Central, 2013) Frédéric Lardeux; Claudia Aliaga; Rosenka Tejerina; Libia Torrez
Conozca mejor al mal de Chagas
(Centre National de la Recherche Scientifique, 2021) Frédéric Lardeux; Wendy Buhezo; Libia Torrez
International audience
Detection of Anopheles pseudopunctipennis (Diptera: Culicidae) in Cochabamba, Bolivia, after 90 years of suspected presence
(2025) Libia Torrez; Lineth Garcia; Silvia Castellón; Rubén Castillo; Frédéric Lardeux
Abstract Objectives. This study provides the first confirmed record of the malaria vector Anopheles pseudopunctipennis in Cochabamba city, Bolivia, ending nearly 90 years of suspected presence since the malaria epidemics of the 1930s and 1940s. Additionally, it assesses the potential suitability of the region for this mosquito species. Methods Mosquito larvae were collected as part of a comprehensive survey of Culicidae in Cochabamba city and its suburbs. Larvae of An. pseudopunctipennis were collected on April 16, 2024, and reared to the fourth instar in the laboratory. One male specimen obtained from collected larvae was pinned. Specimens were morphologically identified using a standard identification key and species re-description. The larval identification was based on its unique spiracular apparatus, while adults were identified by their characteristic black hind tarsomeres and unspotted wing costa. The specimens are preserved in the Laboratory of Medical Entomology at UMSS, Cochabamba. Results A single larval habitat was identified in Lincoln Park, in the center of Cochabamba. It consisted of a 184 m² pond with a cement bottom, clear water with very slow flow from a small spring, and abundant Rhizoclonium algae. A Maxent habitat suitability model indicated that the Cochabamba Valley provides suitable environmental conditions for An. pseudopunctipennis . Conclusions This study provides the first concrete evidence of An. pseudopunctipennis in Cochabamba city, confirming its presence after decades of speculation. However, its low abundance and limited larval habitats due to urbanization and pollution suggest that it poses no significant malaria transmission risk in the area.
Culex (Culex) acharistus, Root, 1927 (Diptera: Culicidae), a new record for Bolivia
(2025) Frédéric Lardeux; Philippe Boussès; Carolina Quezada; Audric Berger; Rosenka Lardeux; Claudia Aliaga; Libia Torrez
Abstract This study reports the first confirmed records of Culex (Culex) acharistus, Root, 1927 in Bolivia, based on both morphological examination and biomolecular identification using the cytochrome c oxidase subunit I (COI) marker. Specimens were collected in four localities representing diverse environmental settings: La Paz (urban environment, ≍3600 m), the nearby high-altitude city of El Alto (≍4000 m), Cochabamba (semi-rural and urban habitats, ≍2600 m), and Licoma a large village in the Yungas region (subtropical environment, ≍1900 m). The larval habitats where the species was found closely match those reported in neighboring countries where Cx. acharistus also occurs, ranging from typical small peridomestic sites to ponds, ditches, and river seepages in semi-rural areas. All identification methods yielded unambiguous results, confirming the species’ presence in Bolivia and extending its known distribution in South America. This finding highlights the importance of integrating morphological and molecular approaches to achieve accurate and reliable mosquito species identification.
Laboratory colonization of Anopheles pseudopunctipennis (Diptera: Culicidae) without forced mating
(Elsevier BV, 2007) Frédéric Lardeux; Vicente Quispe; Rosenka Tejerina; Roberto Rodríguez; Libia Torrez; Bernard Bouchité; Tamara Chávez
Anopheles pseudopunctipennis is one of the main malaria vectors in the Andean regions of South America. Few experimental data exist on this species because it is not very available in laboratories due to its eurygamic status that makes colony maintenance difficult. Indeed, individuals do not mate in the confined space of insectary cages. To avoid this problem, forced artificial mating can be used. However, this technique is time consuming, requires a well-trained technician, and is inadequate for easy mass production, which is sometimes necessary for certain experimental works. This study presents a technique based on exposure of adult mosquitoes to a blue stroboscopic light for 20 min during several nights, which encourages them to copulate naturally under laboratory conditions. After some generations, a self-free-mating strain was obtained. The technique is simple, inexpensive and is probably effective whatever the An. pseudopunctipennis strain considered.
Statistical analysis of larval postspiracular filament length reveals continuous variation in Bolivian Anopheles pseudopunctipennis (Diptera: Culicidae)
(2025) Frédéric Lardeux; D. Albornoz Vásquez; Rosenka Tejerina; Claudia Aliaga; Lineth García; Libia Torrez
Abstract Anopheles pseudopunctipennis is a neotropical malaria vector widely distributed from northern Argentina and Chile to the southern United States. At the larval stage, it is characterized by posterior-lateral caudal filaments, which vary markedly in length within the same samples in Bolivia, with some individuals displaying unusually long filaments. The coexistence of individuals with relatively long and relatively short filaments raises the question of whether at least two distinct populations could be differentiated based on caudal filament length. This study examined filament-length distributions in two Bolivian dry-valley populations, El Chaco and Mataral, to determine whether variation reflects distinct subpopulations or continuous phenotypic variation within a single population. Distributions deviated from normality, exhibiting moderate skewness and tail heaviness, and the Generalized Error Distribution provided the best statistical fit. Examination of outliers and a targeted analysis of the distribution tail using multiple complementary methods showed that extreme values did not form a discrete secondary cluster but rather represented the upper continuum of the trait range. The two sites showed broadly comparable distributions, consistent with similar environmental conditions. These results emphasize the importance of using appropriate distributional models for continuous traits, highlight the occurrence of rare extreme phenotypes within otherwise homogeneous populations, and provide a baseline for future studies on the ecological and genetic determinants of caudal filament variation in An. pseudopunctipennis .
Study of the fauna of disease vector mosquitoes in the metropolitan area of Cochabamba
(Centre National de la Recherche Scientifique, 2022) Libia Torrez; Lineth García; Frédéric Lardeux