Pyrethroid susceptibility reversal in Aedes aegypti: A longitudinal study in Tapachula, Mexico.

Pyrethroid resistance in Aedes aegypti has become widespread after almost two decades of frequent applications to reduce the transmission of mosquito-borne diseases. Because few insecticide classes are available for public health use, insecticide resistance management (IRM) is proposed as a strategy to retain their use. A key hypothesis of IRM assumes that negative fitness is associated with resistance, and when insecticides are removed from use, susceptibility is restored.

Entomopathogenic fungi for the control of larvae and adults of Aedes aegypti (Diptera: Culicidae) vector of dengue, chikungunya and Zika viruses in Mexico.

Objective: To assess larvicide and adulticide activity of different native strains of fungi on Aedes aegypti.

Materials And Methods: Third instar larvae were exposed for 72 h at a concentration of 1x108 conidia/ml of 15 fungi; only fungi that significantly affected the larvae were evaluated against the adult phase at a concentration of 2x1010 conidia/ml. Mortality readings were performed at 24, 48, and 72 h for larvae, and every day to 30 days for adults.

Evaluation of commercial aerosol insecticides for control of Aedes aegypti susceptible or resistant to pyrethroids.

Objective: To evaluate indoor use of commercial aerosols for dengue vector mosquito control, and estimate the number of treatable houses per can.

Materials And Methods: Four aerosol products containing combinations of pyrethroids (two containing propoxur and one containing synergists too), were evaluated with mosquitoes in a room of a Tapachulastyle house. Eight cages containing 20 insecticide susceptible or resistant females were hung from tripods, another set was placed in sheltered areas of the room.

, and Adults Found Coexisting in Urban and Semiurban Dwellings of Southern Chiapas, Mexico.

Tapachula, Mexico, a tropical city, is an endemic area for dengue, in addition to several outbreaks in the last decade with chikungunya and zika. As part of the migratory corridor from Central to North America and the risks of scattered infectious diseases that this implies, the identification and distribution of potential disease vectors in and around residential areas are essential in terms of entomological surveillance for the prevention of disease outbreaks. The identification of mosquito species of medical importance coexisting in houses and cemeteries in Tapachula and two semiurban sites in southern Chiapas was investigated.

Current enzyme-mediated insecticide resistance status of Aedes aegypti populations from a dengue-endemic city in southern Mexico.

Objective: To identify the enzyme-mediated insecticide resistance in Aedes aegypti in Tapachula, Mexico.

Materials And Methods: Biochemical assays were undertaken to determine the enzyme levels in mosquitoes from 22 sites collected in 2018 and 2020 in Tapachula. Results of 2018 were correlated with the resistance to insecticides pub-lished.

Insecticide resistance in Aedes aegypti from Tapachula, Mexico: Spatial variation and response to historical insecticide use.

Background: Insecticide use continues as the main strategy to control Aedes aegypti, the vector of dengue, Zika, chikungunya, and yellow fever. In the city of Tapachula, Mexico, mosquito control programs switched from pyrethroids to organophosphates for outdoor spatial spraying in 2013. Additionally, the spraying scheme switched from total coverage to focused control, prioritizing areas with higher entomological-virological risk.

Permethrin resistance in Aedes aegypti: Genomic variants that confer knockdown resistance, recovery, and death.

Pyrethroids are one of the few classes of insecticides available to control Aedes aegypti, the major vector of dengue, chikungunya, and Zika viruses. Unfortunately, evolving mechanisms of pyrethroid resistance in mosquito populations threaten our ability to control disease outbreaks. Two common pyrethroid resistance mechanisms occur in Ae.

Permethrin Resistance Status and Associated Mechanisms in Aedes albopictus (Diptera: Culicidae) From Chiapas, Mexico.

There are major public health concerns regarding the spread of mosquito-borne diseases such as dengue, Zika, and chikungunya, which are mainly controlled by using insecticides against the vectors, Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse). Pyrethroids are the primary class of insecticides used for vector control, due to their rapid knockdown effect and low toxicity to vertebrates. Unfortunately, continued use of pyrethroids has led to widespread insecticide resistance in Ae.

[Insecticide resistance in Aedes aegypti and Ae. albopictus (Diptera: Culicidae) populations from Tapachula, Chiapas, Mexico].

Objective: To determine the insecticide resistance status of Ae. aegypti and Ae. albopictus from Tapachula, México.

Composition and abundance of anopheline species according to habitat diversity in Mexico.

Objective: To determine the abundance and geographic distribution of the main malaria vectors, which are influenced by habitat characteristics and ecological factors that directly impact adult density and the dynamics of malaria transmission in Mexico.

Materials And Methods: Samples of larvae were collected from 19 states in Mexico. Each larval habitat was characterized in situ determining the following parameters: water depth, turbidity, percentage of vegetation cover, amount of detritus, presence of algae, light intensity, type of vegetation, amount of predators, habitat stability, altitude, and hydrologic type.

Determination of insecticides' lethal concentrations and metabolic enzyme levels in Triatoma dimidiata.

Objective: The feasibility of the use of WHO impregnated paper and biochemical assays to determine lethal concentrations (LC50 and LC99) and insecticide metabolic enzyme levels of Triatoma dimidiata.

Materials And Methods: LC50 and LC99 were calculated with WHO papers impregnated at different concentrations of malathion, propoxur and deltamethrin; the percentage of insensitive acetylcholinesterase (iAChE); and the levels of esterases, glutathione S-transferases, and monooxygenases in laboratory nymphs of the first stage (5 to 7 days), were undertaken using the WHO biochemical assays.

Results: Respectively the LC50 and LC99 μg/cm2 obtained for malathion were 43.

[Indoor thermal fogging of the mixture of flupyradifurone and transflutrin on Aedes aegypti mosquitoes susceptible and resistant to pyrethroids in southern Mexico].

Objective: To evaluate the efficacy of thermal fogging of a mixture of flupyrafirudone (26.3 g/L) and transfluthrin (52.5 g/L) against dengue, Zika y chikungunya Aedes mosquito vectors.

Comparison of two DNA extraction methods from larvae, pupae, and adults of .

Mosquitoes are the most important arthropods from the point of view of public health, due to the fact that they can transmit a large number of pathogens which can cause diseases to humans and animals. (L.) is one of the most important vector species in the world, since it can transmit numerous pathogens such as dengue, Zika, and chikungunya.

A reverse-transcription/RNase H based protocol for depletion of mosquito ribosomal RNA facilitates viral intrahost evolution analysis, transcriptomics and pathogen discovery.

Identifying novel viruses or assessing viral variation by NGS requires high sequencing coverage. More than 90% of total RNA is ribosomal (rRNA), making variant calling, virus discovery or transcriptomic profiling difficult. Current methods to increase informative reads suffer from drawbacks, either they cannot be used for some viruses, are optimized for a single species, or introduce bias.

Mechanisms of pyrethroid resistance in Aedes (Stegomyia) aegypti from Colombia.

In Colombia Aedes (Stegomyia) aegypti is the main vector of urban arboviruses such as dengue, chikungunya and Zika. This urban mosquito has a well-established capacity to develop insecticide resistance to different types of insecticides (pyrethroids, organochlorides, organophosphates), using multiple resistance mechanisms. An understanding of ongoing resistance mechanisms is critical to determining the activities of vector control programs.

Estimating the effects of variation in viremia on mosquito susceptibility, infectiousness, and R0 of Zika in Aedes aegypti.

Zika virus (ZIKV) is an arbovirus primarily transmitted by Aedes mosquitoes. Like most viral infections, ZIKV viremia varies over several orders of magnitude, with unknown consequences for transmission. To determine the effect of viral concentration on ZIKV transmission risk, we exposed field-derived Ae.

Variation in competence for ZIKV transmission by Aedes aegypti and Aedes albopictus in Mexico.

Background: ZIKV is a new addition to the arboviruses circulating in the New World, with more than 1 million cases since its introduction in 2015. A growing number of studies have reported vector competence (VC) of Aedes mosquitoes from several areas of the world for ZIKV transmission. Some studies have used New World mosquitoes from disparate regions and concluded that these have a variable but relatively low competence for the Asian lineage of ZIKV.

Larval habitat characterization of Anopheles darlingi from its northernmost geographical distribution in Chiapas, Mexico.

Background: Anopheles darlingi is considered the most efficient malaria vector in the Neotropical region. In Mexico, its role as an incriminated vector of Plasmodium has not been confirmed in the Lacandon forest. Similarly, knowledge about bionomic and larval ecology is scarce.

Socioeconomic factors, attitudes and practices associated with malaria prevention in the coastal plain of Chiapas, Mexico.

Background: Mexico is in the malaria pre-elimination phase; therefore, continuous assessment and understanding of the social and behavioural risk factors related to exposure to malaria are necessary to achieve the overall goal. The aim of this research was to investigate socio-economic backgrounds, attitudes and practices related with malaria in rural locations from the coastal plain of Chiapas.

Methods: In January 2012, 542 interviews were conducted to householders from 20 villages across the coastal plain of Chiapas.

Effectiveness of indoor ultra-low volume application of Aqua Reslin® Super during an emergency.

Indoor ultra-low volume (ULV) applications of Aqua Reslin Super (Permethrin + s-bioallethrin) were carried out using portable Solo Port 423 sprayers in an urban area of Reforma, Chiapas, Mexico. Sprayers were calibrated to discharge a flow rate of 110 ml/min with a dose range of approximately 0.55 to 0.

Towards a genetic map for Anopheles albimanus: identification of microsatellite markers and a preliminary linkage map for chromosome 2.

Fifty microsatellite loci were identified in the malaria vector Anopheles albimanus. Markers segregating in F2 progeny of crosses between laboratory strains of An. albimanus were used to construct a preliminary genetic map.

[Susceptibility and insecticide resistance mechanisms in Anopheles albimanus from the southern Yucatan Peninsula, Mexico].

Objective: To diagnose susceptibility levels and insecticide resistance mechanisms in Anopheles albimanus from the southern Yucatan Peninsula (YP), Mexico.

Material And Methods: F1 generation of An. albimanus females, collected from November to December 2005 in six villages in the Othon P.

Acceptability and perceived side effects of insecticide indoor residual spraying under different resistance management strategies.

Objective: To assess household acceptability and perceived side effects of residual indoor pyrethroid (PYR), carbamate and organophosphate insecticides sprayed by annual rotation (ROT), spatial mosaic (MOS), and a single insecticide (DDT or PYR) in communities of the coastal plain of Chiapas, Mexico.

Material And Methods: A questionnaire to assess the acceptability and perceived side effects of indoor insecticides was administered to one member of 30% of the families in eight villages of Chiapas. The association of different insecticide treatments with their responses was evaluated (Chi-square).

Knowledge and beliefs about malaria transmission and practices for vector control in southern Mexico.

Objective: To investigate the knowledge and beliefs about malaria transmission and practices for vector control in eight villages on the coastal plain of Chiapas, Mexico.

Material And Methods: A cross-sectional survey was conducted during May and June 1995 in Chiapas, Mexico. A questionnaire to investigate family structure, knowledge on malaria transmission, preventive measures and attitudes towards seeking treatment was applied to both family heads of a sample of households.