- Universidad Autónoma de Nuevo León, Biology, Department Memberadd
Background The integration of house-screening and long-lasting insecticidal nets, known as insecticide-treated screening (ITS), can provide simple, safe, and low-tech Aedes aegypti control. Cluster randomised controlled trials in two... more
Background The integration of house-screening and long-lasting insecticidal nets, known as insecticide-treated screening (ITS), can provide simple, safe, and low-tech Aedes aegypti control. Cluster randomised controlled trials in two endemic localities for Ae. aegypti of south Mexico, showed that ITS conferred both, immediate and sustained (~2 yr) impact on indoor-female Ae. aegypti infestations. Such encouraging results require further validation with studies quantifying more epidemiologically-related endpoints, including arbovirus infection in Ae. aegypti. We evaluated the efficacy of protecting houses with ITS on Ae. aegypti infestation and arbovirus infection during a Zika outbreak in Merida, Yucatan, Mexico. Methodology/Principal findings A two-arm cluster-randomised controlled trial evaluated the entomological efficacy of ITS compared to the absence of ITS (with both arms able to receive routine arbovirus vector control) in the neighbourhood Juan Pablo II of Merida. Cross-sect...
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Background Insecticide resistance is a serious problem for vector control programmes worldwide. Resistance is commonly attributed to mutations at the insecticide’s target site or increased activity of detoxification enzymes. Methods We... more
Background Insecticide resistance is a serious problem for vector control programmes worldwide. Resistance is commonly attributed to mutations at the insecticide’s target site or increased activity of detoxification enzymes. Methods We determined the knockdown concentration (KC50) and lethal concentration (LC50) of deltamethrin in six natural populations of adult Aedes aegypti from southeastern Mexico. These populations were then selected over five generations using the LC50 from the preceding generation that underwent selection, and the heritability of deltamethrin resistance was quantified. For each generation, we also determined the frequency of the kdr alleles L410, I1016 and C1534, and the levels of activity of three enzyme families (α- and β-esterases, mixed-function oxidases and glutathione S-transferases (GST)) associated with insecticide detoxification. Results There was an increase in KC50 and LC50 values in the subsequent generations of selection with deltamethrin (FS5vs ...
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Background: The continued spread of insecticide resistance in mosquito vectors of malaria and arboviral diseases may lead to operational failure of insecticide-based interventions if resistance is not monitored and managed efficiently.... more
Background: The continued spread of insecticide resistance in mosquito vectors of malaria and arboviral diseases may lead to operational failure of insecticide-based interventions if resistance is not monitored and managed efficiently. This study aimed to develop and validate a new WHO glass bottle bioassay method as an alternative to the WHO standard insecticide tube test to monitor mosquito susceptibility to new public health insecticides with particular modes of action, physical properties or both.Methods: A multi-centre study involving 21 laboratories worldwide generated data on the susceptibility of seven mosquito species (i.e. Aedes aegypti, Ae. albopictus, Anopheles gambiae s.s., An. funestus, An. stephensi, An. minimus and An. albimanus) to seven public health insecticides in five classes, including pyrethroids (metofluthrin, prallethrin, and transfluthrin), neonicotinoids (clothianidin), pyrroles (chlorfenapyr), juvenile hormone mimics (pyriproxyfen) and butenolides (flupyr...
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Triatoma longipennis Usinger 1939, Triatoma pallidipennis (Stal, 1872), and Triatoma picturata Usinger 1939 are considered among the species with the highest transmission capacity of Chagas disease in Mexico, with an impact on health... more
Triatoma longipennis Usinger 1939, Triatoma pallidipennis (Stal, 1872), and Triatoma picturata Usinger 1939 are considered among the species with the highest transmission capacity of Chagas disease in Mexico, with an impact on health mainly in rural zones and places with worn-out dwellings. There have been previous studies on the phylogenetic relationship of these species of the Phyllosoma complex using molecular approaches, in addition to analyzing morphological characters. However, one of the problems in the field is the presence of hybrids that due to the short genetic distance between species, and such organisms have not yet been identified and could be confused with parental organisms. In this work, we analyzed genotypical and phenotypic characters, between the species and the three possible hybrids resulting from the cross between the species. In the analysis of wings morphology, we found that the dominant phenotype in hybrids was that of T. pallidipennis, having a higher dominance than T. longipennis. Besides, the use of the COI marker amplified in DNA of parentals and the three possible hybrids showed by neighbor-joining phylograms a greater association of the hybrids with T. longipennis, in agreement with the analysis of genetic distances and polymorphic sites. Thus, the morphological data demonstrate the high dominance of T. pallidipennis and the molecular data of T. longipennis in its hybrids, in such a way that it is possible to differentiate hybrids from parental species.
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The mosquito Aedes aegypti is the principal vector of dengue and yellow fever flaviviruses. Permethrin is an insecticide used to suppress Ae. aegypti adult populations but metabolic and target site resistance to pyrethroids has evolved in... more
The mosquito Aedes aegypti is the principal vector of dengue and yellow fever flaviviruses. Permethrin is an insecticide used to suppress Ae. aegypti adult populations but metabolic and target site resistance to pyrethroids has evolved in many locations worldwide. Quantitative trait loci (QTL) controlling permethrin survival in Ae. aegypti were mapped in an F3 advanced intercross line. Parents came from a collection of mosquitoes from Isla Mujeres, México, that had been selected for permethrin resistance for two generations and a reference permethrin-susceptible strain originally from New Orleans. Following a 1-hr permethrin exposure, 439 F3 adult mosquitoes were phenotyped as knockdown resistant, knocked down/recovered, or dead. For QTL mapping, single nucleotide polymorphisms (SNPs) were identified at 22 loci with potential antixenobiotic activity including genes encoding cytochrome P450s (CYP), esterases (EST), or glutathione transferases (GST) and at 12 previously mapped loci. ...
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Research Interests: Zoology, Biology, Venezuela, Medicine, Aedes aegypti, and 14 moreInsecticides, Insecticide Resistance, Nitriles, Female, Animals, Fecundity, Esterases, Glutathione Transferase, Pest Management Science, Aedes, ENVIRONMENTAL SCIENCE AND MANAGEMENT, Deltamethrin, Biological parameters, and Detoxifying enzymes
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Introducción. El dengue es un problema de salud pública para el departamento de La Guajira. El control se ha enfocado en el vector con el uso de insecticidas, entre ellos los organofosforados.Objetivo. Evaluar el estado de la sensibilidad... more
Introducción. El dengue es un problema de salud pública para el departamento de La Guajira. El control se ha enfocado en el vector con el uso de insecticidas, entre ellos los organofosforados.Objetivo. Evaluar el estado de la sensibilidad a insecticidas organofosforados de quince poblaciones de Aedes aegypti (L.) en el departamento de La Guajira, Colombia.Materiales y métodos. Se realizaron bioensayos para temefos, malatión y metil-pirimifos en larvas de tercer estadio y mosquitos adultos de Ae. aegypti en los municipios de Albania, Barrancas, Dibulla, Distracción, El Molino, Fonseca, Hatonuevo, La Jagua del Pilar, Maicao, Manaure, Riohacha, San Juan del Cesar, Uribia, Urumita y Villanueva, siguiendo la metodología de la Organización Mundial de la Salud (OMS) y la técnica de botellas usando la guía de los de los Centers for Disease Control and Prevention, respectivamente. Se determinó la sensibilidad por medio de la razón de resistencia a CL50 y CL95 (RRCL50, RRCL95) para temefos y a dosis y tiempo diagnóstico para temefos, malatión y metilpirimifos en las poblaciones de campo evaluadas, usando como control la cepa sensible Rockefeller.Resultados. Las 15 poblaciones del departamento de La Guajira son sensibles a: temefos (razón de la resistencia a RRCL50<5,0; relación de resistencia a CL95<5,0; 98 a 100 % de mortalidad); metil-pirimifos (99 a 100 % de mortalidad) y malatión (100 % de mortalidad). Conclusión. Con base en los resultados obtenidos, es factible el uso de temefos, malatión y metil-pirimifos para el control de Ae. aegypti en las poblaciones evaluadas.
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Los piretroides son los insecticidas mas utilizados para el control de mosquitos adultos. Dos mecanismos han sido implicados como responsable de la resistencia a los piretroides: la sobreexpresion de enzimas de desintoxicacion y la... more
Los piretroides son los insecticidas mas utilizados para el control de mosquitos adultos. Dos mecanismos han sido implicados como responsable de la resistencia a los piretroides: la sobreexpresion de enzimas de desintoxicacion y la insensibilidad en el sitio blanco. La resistencia kdr (knockdown resistance) o resistencia al derribo, se refiere a uno de los dos principales tipos de resistencia a piretroides y DDT, la cual se evidencia porque los insectos no pierden la coordinacion inmediatamente despues de la exposicion al insecticida. Se debe a la presencia de mutaciones puntuales en el gen que codifica para el canal de sodio, donde el aminoacido resultante ocasiona una reduccion en la union al insecticida sin perdida de la funcion primaria del sitio blanco. En 1975 en Tailandia, se registro la resistencia de tipo kdr por primera vez en Aedes aegypti (L.), tras el fracaso de una campana de control con bioresmetrina. Los estudios geneticos de una cepa seleccionada a partir de esta poblacion demostraron la presencia de un factor de resistencia unica a los piretroides (Rpy) presentes en el cromosoma III, que mostro dominancia incompleta (Soderlund y Bloomquist 1990). A nivel mundial se han determinado numerosas mutaciones confiriendo resistencia a piretroides en Ae. aegypti (S989P; I1,011M; I1,011V; V1,016I; V1,016G; F1,534C; and D1,794Y) (Vontas et al. 2012, Rinkevich et al. 2013), e incluso tres de estas (I1,011M; I1,011V; y F1,534C) tambien se han detectado en Ae. albopictus (Kasai et al. 2011, McAllister et al. 2012, Vontas et al. 2012, Rinkevich et al. 2013). A pesar de que varias mutaciones en el gen del canal de sodio se han asociado con fenotipos resistentes a piretroides y DDT; hay controversias sobre el papel que estos desempenan en la resistencia. Brooke (2008) observo que la resistencia podria ser multigenica y que las mutaciones en el gen del canal de sodio por si solas no podian explicar completamente el fenotipo resistente. Particularmente, la mutacion F1534C que se habia correlacionado con la resistencia piretroides tipo I pero no a tipo II (Harris et al. 2010, Hu et al. 2011 y Yanola et al. 2011). Contrariamente a estos informes, Alvarez et al (2014) demostro la participacion de esta mutacion en la resistencia a la deltametrina en una cepa proviniente de Venezuela seleccionada por 15 generaciones con este insecticida. Estudios recientes sugieren que las mutaciones kdr tienen un alto costo biologico en Ae. aegypt i en la ausencia de los piretroides y que la reversion de las frecuencias de los alelos kdr podria ocurrir si se elimina la presion con el insecticida (Chang et al. 2012, Martins et al. 2012, Brito et al. 2013). Tal vez este sea el mayor obstaculo para la implementacion de un sistemas de manejo sostenible de la resistencia a piretroides, que las frecuencias alelicas altas de una mutacion en particular a piretroides puedan revertirse cuando la presion con piretroides sea reducida o eliminada y que pueda rotarse con otros insecticidas para mantener este mecanismo de resistencia bajo y que no signifique un obstaculo en el control eficaz de las poblaciones de Ae. aegypti .
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Emerging and re-emerging vector-borne infections are a global public health threat. In endemic regions, fever is the main reason for medical attention, and the etiological agent of such fever is not usually identified. In this study,... more
Emerging and re-emerging vector-borne infections are a global public health threat. In endemic regions, fever is the main reason for medical attention, and the etiological agent of such fever is not usually identified. In this study, non-specific febrile pathogens were molecularly characterized in serum samples from 253 patients suspected of arbovirus infection. The samples were collected in the southern border region of Mexico from April to June 2015, and February to March 2016. ZIKV, CHIKV, DENV, leptospirosis, and rickettsiosis were detected by qPCR and nested PCR to identify flavivirus and alphavirus genera. The results indicated that 71.93% of the samples were positive for CHIKV, 0.79% for ZIKV, and 0.39% for DENV, with the number positive for CHIKV increasing to 76.67% and those positive for ZIKV increasing to 15.41% under the nested PCR technique. Leptospira Kmetyi was identified for the first time in Mexico, with a prevalence of 3.16%. This is the first report of ZIKV in Mex...
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Living organisms have been exposed to light-dark cycles that allowed them to adapt to different ecological niches. Circadian cycles affect hormone release, metabolism, and response to xenobiotic compounds. Current studies have shown that... more
Living organisms have been exposed to light-dark cycles that allowed them to adapt to different ecological niches. Circadian cycles affect hormone release, metabolism, and response to xenobiotic compounds. Current studies have shown that insect susceptibility to toxic agents depends on circadian cycles, mainly because the biochemical processes involved in detoxification and responses to oxidative stress are modulated by this process. The goal of this study was to determine the effect of photoperiod on resistance to permethrin in Aedes aegypti . Collections of Ae. aegypti from 4 locations in Yucatan, southern Mexico, were subjected to 2 different photoperiod schemes: dark (0 h light:24 h dark) and natural photoperiod (12 h light:12 h dark). The comparison of both photoperiods was evaluated with respect to permethrin resistance using bottle bioassays and by monitoring the possible mechanism related such as enzymatic activity and by the frequency of 2 knockdown resistance mutations in ...
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BACKGROUNDKnockdown resistance is conferred primarily by non‐synonymous mutations that reduce pyrethroids binding to voltage‐gated sodium channels. In 2014, kdr mutation V1016I in Aedes aegypti populations resistant to pyrethroids was... more
BACKGROUNDKnockdown resistance is conferred primarily by non‐synonymous mutations that reduce pyrethroids binding to voltage‐gated sodium channels. In 2014, kdr mutation V1016I in Aedes aegypti populations resistant to pyrethroids was reported for the first time in Colombiα, in 2016 another kdr mutation, F1534C, and in 2018 the mutation V419L. Nine populations of A. aegypti, previously characterized as being resistant to λ‐cyhalothrin, deltamethrin, cyfluthrin and permethrin, were used for this study. Genomic DNA was used to determine genotypes by allele‐specific PCR for mutations V1016I and F1534C, and to determine their association with pyrethroid resistance.RESULTSAll the populations analyzed showed both mutations, with allelic frequencies of 0.07–0.35 for I1016 and 0.47–0.88 for C1534. A percentage of co‐occurrence of mutant homozygotes I1016/C1534 of 5.3% was detected. A significant positive correlation was found between the frequency of the genotype I1016 and the resistance to...
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Resistance to insecticides through one or several mechanisms has a cost for an insect in various parameters of its biological cycle. The present study evaluated the effect of deltamethrin on detoxifying enzymes and biological parameters... more
Resistance to insecticides through one or several mechanisms has a cost for an insect in various parameters of its biological cycle. The present study evaluated the effect of deltamethrin on detoxifying enzymes and biological parameters in a population of Aedes aegypti selected for 15 generations. The enzyme activities of alpha- and beta-esterases, mixed-function oxidases and glutathione-S-transferases were determined during selection, along with biological parameters. Overexpression of mixed-function oxidases as a mechanism of metabolic resistance to deltamethrin was found. There were decreases in percentages of eggs hatching, pupation and age-specific survival and in total survival at the end of the selection (F16 ). Although age-specific fecundity was not affected by selection with deltamethrin, total fertility, together with lower survival, significantly affected gross reproduction rate, gradually decreasing due to deltamethrin selection. Similarly, net reproductive rate and int...
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RESUMEN. Se llevo a cabo la evaluación de los efectos sobre algunos parámetros biológicos de la eliminación de bacterias simbióticas de Aedes aegypti (L.) usando el antibiótico penicilina. La administración de penicilina (200ppm) incluida... more
RESUMEN. Se llevo a cabo la evaluación de los efectos sobre algunos parámetros biológicos de la eliminación de bacterias simbióticas de Aedes aegypti (L.) usando el antibiótico penicilina. La administración de penicilina (200ppm) incluida en solución de sacarosa al 10% posterior a 5 días de inanición mostro ser una técnica efectiva para el consumo por parte del mosquito y la eliminación de las bacterias simbióticas del intestino medio de hembras de Ae. aegypti hasta en un 100%. Esto se comprobó posteriormente en cultivos con medios BHI y LB. Dicha eliminación mostro tener efectos notorios en la fecundidad y la supervivencia de las hembras de la colonia tratada, así como su F 1 , mientras que en la fertilidad y longitud alar no se mostro alteración significativa. Palabras claves: Aedes aegypti, penicilina, simbiontes, fecundidad, fertilidad.
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Introducción Los insecticidas juegan un papel central en el control de vectores de enfermedades tales como mosquitos, moscas, pulgas, piojos, chinches, etc. En 1955 la OMS propuso la erradicación global de una de las enfermedades más... more
Introducción Los insecticidas juegan un papel central en el control de vectores de enfermedades tales como mosquitos, moscas, pulgas, piojos, chinches, etc. En 1955 la OMS propuso la erradicación global de una de las enfermedades más prevalecientes transmitidas por vectores, la malaria, con el uso de rociados residuales intradomiciliares de DDT. Sin embargo la euforia por los insecticidas terminó pronto y en 1976 la OMS revirtió su concepto de erradicación a control de la malaria. Los cambios en la política se debieron a la aparición de la resistencia al DDT en un gran número de mosquitos vectores. En 1975 la OMS reportó que una población de 256 millones de personas vivían en áreas donde la resistencia a DDT y/o los BHC (Bifenil Poli Clorinados) mermaron los esfuerzos para el control de la malaria. (Esto no incluyó a la región de Africa, en donde ocurren el 90% de los casos de Malaria y donde ya se había registrado resistencia de Anopheles gambiae al DDT, el principal vector de mala...
Understanding mechanisms driving insecticide resistance in vector populations remains a public health priority. To date, most research has focused on the genetic mechanisms underpinning resistance, yet it is unclear what role... more
Understanding mechanisms driving insecticide resistance in vector populations remains a public health priority. To date, most research has focused on the genetic mechanisms underpinning resistance, yet it is unclear what role environmental drivers may play in shaping phenotypic expression. One of the key environmental drivers of Aedes aegypti mosquito population dynamics is resource-driven intraspecific competition at the larval stage. We experimentally investigated the role of density-dependent larval competition in mediating resistance evolution in Ae. aegypti, using knockdown resistance (kdr) as a marker of genotypic resistance and CDC bottle bioassays to determine phenotype. We reared first-instar larvae from susceptible and pyrethroid-resistant field-derived populations of Ae. aegypti at high and low density and measured the resulting phenotypic resistance and population kdr allele frequencies. At low density, only 48.2% of the resistant population was knocked down, yet at high...
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Aedes aegypti is the primary urban mosquito vector of viruses causing dengue, Zika and chikungunya fevers -for which vaccines and effective pharmaceuticals are still lacking. Current strategies to suppress arbovirus outbreaks include... more
Aedes aegypti is the primary urban mosquito vector of viruses causing dengue, Zika and chikungunya fevers -for which vaccines and effective pharmaceuticals are still lacking. Current strategies to suppress arbovirus outbreaks include removal of larval-breeding sites and insecticide treatment of larval and adult populations. Insecticidal control of Ae. aegypti is challenging, due to a recent rapid global increase in knockdown-resistance (kdr) to pyrethroid insecticides. Widespread, heavy use of pyrethroid space-sprays has created an immense selection pressure for kdr, which is primarily under the control of the voltage-gated sodium channel gene (vgsc). To date, eleven replacements in vgsc have been discovered, published and shown to be associated with pyrethroid resistance to varying degrees. In Mexico, F1,534C and V1,016I have co-evolved in the last 16 years across Ae. aegypti populations. Recently, a novel replacement V410L was identified in Brazil and its effect on vgsc was confir...
Resistance to insecticides through one or several mechanisms has a cost for an insect in various parameters of its biological cycle. The present study evaluated the effect of deltamethrin on detoxifying enzymes and biological parameters... more
Resistance to insecticides through one or several mechanisms has a cost for an insect in various parameters of its biological cycle. The present study evaluated the effect of deltamethrin on detoxifying enzymes and biological parameters in a population of Aedes aegypti selected for 15 generations. The enzyme activities of alpha- and beta-esterases, mixed-function oxidases and glutathione-S-transferases were determined during selection, along with biological parameters. Overexpression of mixed-function oxidases as a mechanism of metabolic resistance to deltamethrin was found. There were decreases in percentages of eggs hatching, pupation and age-specific survival and in total survival at the end of the selection (F16 ). Although age-specific fecundity was not affected by selection with deltamethrin, total fertility, together with lower survival, significantly affected gross reproduction rate, gradually decreasing due to deltamethrin selection. Similarly, net reproductive rate and intrinsic growth rate were affected by selection. Alterations in life parameters could be due to the accumulation of noxious effects or deleterious genes related to detoxifying enzymes, specifically those coding for mixed-function oxidases, along with the presence of recessive alleles of the V1016I and F1534C mutations, associating deltamethrin resistance with fitness cost in Ae. aegypti. © 2017 Society of Chemical Industry.
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... 503 PRICKLY PEAR CACTI PESTS AND THEIR CONTROL IN MEXICO MOHAMMAD H. BADII AND ADRIANA E. FLORES Autonomous University of Nuevo Leon, Ap. ... Chemical insecticides used to control this pest include azin-phosmethyl, endosulfan,... more
... 503 PRICKLY PEAR CACTI PESTS AND THEIR CONTROL IN MEXICO MOHAMMAD H. BADII AND ADRIANA E. FLORES Autonomous University of Nuevo Leon, Ap. ... Chemical insecticides used to control this pest include azin-phosmethyl, endosulfan, malathion, and folidol. ...
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Oligosaccharides have been marketed since the 1980s as low calories agents and recently have gained interest in the pharmaceutical and food industry as functional sweeteners and prebiotic enriching population of Bifidobacteria. Currently,... more
Oligosaccharides have been marketed since the 1980s as low calories agents and recently have gained interest in the pharmaceutical and food industry as functional sweeteners and prebiotic enriching population of Bifidobacteria. Currently, they have an approximated value of $ 200 per kg and recently, inulin has been proposed as a feedstock for production of oligosaccharides through selective hydrolysis by action of endoinulinase. High optimum temperature (60 °C) and thermostability are two important criteria which determine suitability of this enzyme for industrial applications as well as enzyme cost, a major limiting factor. Significant reduction in cost can be achieved by employing low-value and abundant inulin rich plants as Jerusalem artichoke, dahlia, yacon, garlic and onion, among others. In general, the early-harvested tubers of these plants contain a greater amount of highly polymerized sugar fractions, which offer more industrial value than late-harvested tubers or those after storage. Also, development of recombinant microorganisms could be useful to reduce the cost of enzyme technology for large scale production of oligosaccharides. In the case of fungal inulinases, several studies of cloning and modification have been made to achieve greater efficiency. The present article reviews inulin from vegetable sources as feedstock for oligosaccharides production through the action of inulinases, the impact of polymerization degree of inulin and its availability and some strategies to increase oligosaccharides production.
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Información del artículo Salud y vida cotidiana en el ámbito doméstico en la población trabajadora de una empresa farmacéutica.
Biblioteca de la Universidad Complutense de Madrid, Base de datos de artículos de revistas, ...
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Pyrethroid resistance can be considered one of the main problems to the control of many mosquito vectors of diseases. The use of synergists is one of the strategies used to help increase the efficacy of certain insecticides. This... more
Pyrethroid resistance can be considered one of the main problems to the control of many mosquito vectors of diseases. The use of synergists is one of the strategies used to help increase the efficacy of certain insecticides. This investigation demonstrates the efficacy of S,S,S-tributylphosphorotrithioate (DEF) and piperonyl butoxide (PBO) with permethrin against 2 strains of Aedes aegypti with high resistance levels 18-fold of RR KD50 (knockdown resistance) and 12-fold of RR CL50 (24-h postrecovery resistance) to this pyrethroid. Mosquito larvae were used for testing the synergistic effect. The DEF was used at a concentration of 0.03 mg/liter and for PBO stock solutions of permethrin and PBO were mixed in 16 ratio. The synergistic ratio and the percent suppression in permethrin tolerance were calculated by using LC50 values. The results show that DEF is more effective synergist against the 2 strains used in this investigation compared with PBO. The results also suggests the role of nonspecific esterases as resistance mechanisms to permethrin.