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Argueta A.L.,Autonomous University of Chiapas | Valle J.,COSUR | Marina C.F.,Centro Regional Of Investigacion En Salud Publica Insp
Revista Colombiana de Entomologia | Year: 2011

The ovicidal and larvicidal effects of spinosad were studied in Aedes aegypti treated with concentrations of 0.1, 5 y 10 ppm spinosad (Tracer 480SC) during different periods of exposure at a constant temperature of 25±1°C. In a first experiment the ovicidal effects were low (6.6-8.2% of non-eclosion averaged over 12-96h exposure periods), whereas in a second experiment ovicidal effects were moderate (27,9 - 31,9% of non-eclosion in eggs exposed to spinosad suspension of 1-12 weeks old). Mortality of larvae increased significantly with increasing concentration and increasing duration of exposure to this product. Although spinosad has clear applications as a mosquito control product for control of vectors such as A. aegypti, it is clear that its vector control potential resides in its larvicidal effects rather than its ovicidal activity. Source

Erasmus J.H.,University of Texas Medical Branch | Needham J.,InBios International, Inc. | Raychaudhuri S.,InBios International, Inc. | Diamond M.S.,University of Washington | And 9 more authors.
PLoS Neglected Tropical Diseases | Year: 2015

In December of 2013, chikungunya virus (CHIKV), an alphavirus in the family Togaviridae, was introduced to the island of Saint Martin in the Caribbean, resulting in the first autochthonous cases reported in the Americas. As of January 2015, local and imported CHIKV has been reported in 50 American countries with over 1.1 million suspected cases. CHIKV causes a severe arthralgic disease for which there are no approved vaccines or therapeutics. Furthermore, the lack of a commercially available, sensitive, and affordable diagnostic assay limits surveillance and control efforts. To address this issue, we utilized an insect-specific alphavirus, Eilat virus (EILV), to develop a diagnostic antigen that does not require biosafety containment facilities to produce. We demonstrated that EILV/CHIKV replicates to high titers in insect cells and can be applied directly in enzyme-linked immunosorbent assays without inactivation, resulting in highly sensitive detection of recent and past CHIKV infection, and outperforming traditional antigen preparations. © 2015, Public Library of Science. All rights reserved. Source

Pech-May A.,Centro Regional Of Investigacion En Salud Publica Insp | Pech-May A.,National Autonomous University of Mexico | Marina C.F.,Centro Regional Of Investigacion En Salud Publica Insp | Vazquez-Dominguez E.,National Autonomous University of Mexico | And 7 more authors.
Infection, Genetics and Evolution | Year: 2013

The low dispersal capacity of sand flies could lead to population isolation due to geographic barriers, climate variation, or to population fragmentation associated with specific local habitats due to landscape modification. The phlebotomine sand fly Lutzomyia cruciata has a wide distribution throughout Mexico and is a vector of Leishmania mexicana in the southeast. The aim of this study was to evaluate the genetic diversity, structure, and divergence within and among populations of Lu. cruciata in the state of Chiapas, and to infer the intra-specific phylogeny using the 3' end of the mitochondrial cytochrome b gene. We analyzed 62 sequences from four Lu. cruciata populations and found 26 haplotypes, high genetic differentiation and restricted gene flow among populations (Fst= 0.416, Nm= 0.701, p< 0.001). The highest diversity values were recorded in populations from Loma Bonita and Guadalupe Miramar. Three lineages (100% bootstrap and 7% overall divergence) were identified using a maximum likelihood phylogenetic analysis which showed high genetic divergence (17.2-22.7%). A minimum spanning haplotype network also supported separation into three lineages. Genetic structure and divergence within and among Lu. cruciata populations are hence affected by geographic heterogeneity and evolutionary background. Data obtained in the present study suggest that Lu. cruciata in the state of Chiapas consists of at least three lineages. Such findings may have implications for vector capacity and hence for vector control strategies. © 2013 Elsevier B.V.. Source

Bond J.G.,Centro Regional Of Investigacion En Salud Publica Insp | Casas-Martinez M.,Centro Regional Of Investigacion En Salud Publica Insp | Quiroz-Martinez H.,Autonomous University of Nuevo Leon | Novelo-Gutierrez R.,Institute Ecologia AC | And 5 more authors.
Parasites and Vectors | Year: 2014

Background: The abundance, richness and diversity of mosquitoes and aquatic insects associated with their oviposition sites were surveyed along eight states of the Pacific coast of Mexico. Diversity was estimated using the Shannon index (H'), similarity measures and cluster analysis. Methods. Oviposition sites were sampled during 2-3 months per year, over a three year period. Field collected larvae and pupae were reared and identified to species following adult emergence. Aquatic insects present at oviposition sites were also collected, counted and identified to species or genus. Results: In total, 15 genera and 74 species of mosquitoes were identified: Anopheles pseudopunctipennis, An. albimanus and Aedes aegypti were the most abundant and widely-distributed species, representing 47% of total mosquito individuals sampled. New species records for certain states are reported. Anopheline diversity was lowest in Sinaloa state (H' = 0.54) and highest in Chiapas (H' = 1.61) and Michoacán (H' = 1.56), whereas culicid diversity was lowest in Michoacán (H' = 1.93), Colima (H' = 1.95), Sinaloa (H' = 1.99) and Jalisco (H' = 2.01) and highest in Chiapas (H' = 2.66). In total, 10 orders, 57 families, 166 genera and 247 species of aquatic insects were identified in samples. Aquatic insect diversity was highest in Chiapas, Oaxaca and Michoacán (H' = 3.60-3.75). Mosquito larval/pupal abundance was not correlated with that of predatory Coleoptera and Hemiptera. Conclusion: This represents the first update on the diversity and geographic distribution of the mosquitoes and aquatic insects of Mexico in over five decades. This information has been cataloged in Mexico's National Biodiversity Information System (SNIB-CONABIO) for public inspection. © 2014 Bond et al.; licensee BioMed Central Ltd. Source

May-Concha I.,CONICET | May-Concha I.,Centro Regional Of Investigacion En Salud Publica Insp | Guerenstein P.G.,CONICET | Ramsey J.M.,Centro Regional Of Investigacion En Salud Publica Insp | And 2 more authors.
Infection, Genetics and Evolution | Year: 2016

Triatoma dimidiata (Latreille) is a species complex that spans North, Central, and South America and which is a key vector of all known discrete typing units (DTU) of Trypanosoma cruzi, the etiologic agent of Chagas disease. Morphological and genetic studies indicate that T. dimidiata is a species complex with three principal haplogroups (hg) in Mexico. Different markers and traits are still inconclusive regarding if other morphological differentiation may indicate probable behavioral and vectorial divergences within this complex. In this paper we compared the antennae of three Mexican haplogroups (previously verified by molecular markers ND4 and ITS-2) and discussed possible relationships with their capacity to disperse and colonized new habitats. The abundance of each type of sensillum (bristles, basiconics, thick- and thin-walled trichoids) on the antennae of the three haplogroups, were measured under light microscopy and compared using Kruskal-Wallis non-parametric and multivariate non-parametric analyses. Discriminant analyses indicate significant differences among the antennal phenotype of haplogroups either for adults and some nymphal stages, indicating consistency of the character to analyze intraspecific variability within the complex. The present study shows that the adult antennal pedicel of the T. dimidiata complex have abundant chemosensory sensilla, according with good capacity for dispersal and invasion of different habitats also related to their high capacity to adapt to conserved as well as modified habitats. However, the numerical differences among the haplogroups are suggesting variations in that capacity. The results here presented support the evidence of T. dimidiata as a species complex but show females and males in a different way. Given the close link between the bug's sensory system and its habitat and host-seeking behavior, AP characterization could be useful to complement genetic, neurological and ethological studies of the closely related Dimidiata Complex haplogroups for a better knowledge of their vectorial capacity and a more robust species differentiation. © 2016. Source

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