Abstract:The larvicidal activity of essential oils cinnamon (Cinnamomum verum J. Presl), Mexican lime (Citrus aurantifolia Swingle) cumin (Cuminum cyminum Linnaeus), clove (Syzygium aromaticum (L.) Merr. & L.M.Perry), laurel (Laurus nobilis Linnaeus), Mexican oregano (Lippia berlandieri Schauer) and anise (Pimpinella anisum Linnaeus)) and their major components are tested against larvae and pupae of Culex quinquefasciatus Say. Third instar larvae and pupae are used for determination of lethality and mortality. Essential oils with more than 90% mortality after a 30-min treatment are evaluated at different time intervals. Of the essential oils tested, anise and Mexican oregano are effective against larvae, with a median lethal concentration (LC 50 ) of 4.7 and 6.5 µg/mL, respectively. Anise essential oil and t-anethole are effective against pupae, with LC 50 values of 102 and 48.7 µg/mL, respectively. Oregano essential oil and carvacrol also have relevant activities. A kinetic analysis of the larvicidal activity, the oviposition deterrent effect and assays of the effects of the binary mixtures of chemical components are undertaken. Results show that anethole has synergistic effects with other constituents. This same effect is observed for carvacrol and thymol. Limonene shows antagonistic effect with β-pinene. The high larvicidal and pupaecidal activities of essential oils and its components demonstrate that they can be potential substitutes for chemical compounds used in mosquitoes control programs.

Background: Human papillomaviruses (HPVs), the leading cause of cervical cancer, are distributed worldwide, with high prevalence in developing countries. Objective: The objective of the study is to know the prevalence and genotypes of HPV in women from the state of Michoacán and the Women's Hospital in Morelia, Michoacán. Materials and Methods: Cervical smear samples (159,288) were subjected to HPV detection by hybrid capture 2. A subsample of 484 patients from the Women's Hospital was studied by Papanicolaou test and linear array HPV genotyping, and when positive, patients were also examined by colposcopy and histopathology. Results: The overall prevalence for HPV in Michoacán State was 7.74%; 7.11% in 2009, 6.46% in 2010, 9.58% in 2011, and 8.43% in 2012. The highest prevalence was found in the age groups < 25 and 25-34 years. The prevalence at the Women's Hospital was 8.51%. Cytological examination revealed normal cytology in 64.44% of samples, 26.66 % with low-grade and 8.88 % with high-grade squamous intraepithelial lesion (HSIL). However, by colposcopy, normal tissue appearance was found only in 26.66%; 51% were reclassified as low-grade squamous intraepithelial lesion, 17.77% as HSIL, and in 4.4% atrophy was observed. The most prevalent genotype in single infections was HPV59, followed by HPV51 and HPV45. Double infections occurred with the following genotypes:

In a field-trapping experiment, western balsam bark beetles,Dryocoetes confusus Swaine, were highly attracted to a 5∶1 mixture of (±)-exo-and (±)-endo-brevicomin. Beetles in the sympatric speciesD. affaber (Mann.), were best attracted to a 1∶1 blend of these semiochemicals [either (±)∶(±) or (±)∶(±)], suggesting that both geometrical isomers are pheromone components in these species. In laboratory bioassays and further field experiments, attraction ofD. confusus was greatest when the (+) enantiomers of both geometrical isomers of brevicomin were presented in a 9∶1 ratio. Responses by maleD. confusus to attractive mixtures were reduced in the presence of (-)-exo-brevicomin. Exploitation of the complete range of variability in pheromone structure (both geometrical and optical isomerism) would allow for optimization and regulation of response levels within a species and also could maintain reproductive isolation among sympatric congeneric species primarily through production and response to species-specific blends.

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We studied the morphology and morphometry of scutella from six species of the hemipteran genus Meccus to identify new tools to help solve taxonomic problems in closely related insect species of epidemiological relevance. Scutellum samples were observed by scanning electron microscopy and were subjected to morphometric analysis. The results mainly show differences in central depression shape, posterior process, and vestiture. We found significant dimensional differences in scutellum morphometry and a clear sexual dimorphism among species. A combination of morphology and morphometry can be used to differentiate among species of the genus

Triatoma mexicana is an endemic species of Mexico and is distributed in the states of Hidalgo, Queretaro, Guanajuato, and San Luis Potosi, being naturally infected with Trypanosoma cruzi, which increases its importance in the region. The species description was made in 1848, but there are only a few studies on its morphology, biology, and behavior. The present manuscript shows the presence of morphological and chromatic variations among populations of T. mexicana from the states of Hidalgo (Valle del Mezquital and Meztitlan), Guanajuato and Queretaro. The study employed 136 specimens collected in four locations. Scanning electron microscopy was used to study the morphological characteristics of the head, pronotum, and scutellum; also, we measured the width of the abdomen and the total length in the specimens of each population. The morphometric analysis considered 19 variables in the previous structures. Significant differences were found in the dimensions of the head and pronotum, but not in the scutellum; there is clear discrimination among the four proposed populations. The chromatic patterns observed in the connexivum go from yellow to brown and show some significant differences related to geographical origin. The set of evaluated characters showed a higher degree of difference in the population of Guanajuato, clearly separating from the rest of the populations, indicating the possibility of a divergence process. The characteristics observed in the remaining populations could be adaptive responses to their habitat.

Triatomine classification is based on morphological characteristics. Studies have been conducted to improve their identification by observing many characteristics. However, there are problems of differentiating among highly interrelated species and new criteria are required. The purpose of this study was to determine the morphological differences in the external female genitalia of M. pallidipennis, M. longipennis, M. picturatus, M. bassolsae, M. mazzottii, and M. phyllosomus in order to distinguish among species using scanning electron microscopy. Observations were made of the dorsal, posterior, lateral, and ventral views of the female external genitalia for each species. In the six species we studied, relevant differences were observed in the dorsal view of the X segment, as well as the IX, VIII, and VII tergites. In the posterior and lateral view, the most visible differences were registered in the gonocoxite size of the segments VIII, IX, and X. Finally, in the ventral view of the VII sternite, differences among species were observed in the size of the inflection in the top and upper corner. Our results show that it was possible to differentiate among the triatominae species for each of the four views by using a scanning electron microscope to analyze morphological characteristics of the VII, VIII, IX, and X abdomen segments. Journal of Vector Ecology 42 (2): 271-278. 2017.

We describe and compare the morphology and morphometry of the egg exochorion for five species and two morphotypes of Mexican triatomines with scanning electron microscopy. The results show differences in egg ornamentation for each species, including between morphotypes. Polygonal ornamentation was observed in each species, including pentagons, octagons and, in certain cases, a majority of hexagons. We observed small perforations in T. protracta protracta, small spheres on the T. lecticularia polygons, a crown with festoons in T. barberi, and less complex ornamentation in T. mexicana. Through morphometric analysis, significant differences in egg dimensions were determined for the studied species. Journal of Vector Ecology 38 (1): 90-96. 2013.