Toxicity of spinosad to temephos-resistant Aedes aegypti populations in Brazil.

The mosquito Aedes aegypti is the primary vector of different arboviruses and represents a major public health problem. Several Brazilian populations of Ae. aegypti have developed resistance to temephos, the most used organophosphate larvicide.

MosqTent: An individual portable protective double-chamber mosquito trap for anthropophilic mosquitoes.

Here, we describe the development of the MosqTent, an innovative double-chamber mosquito trap in which a human being attracts mosquitoes while is protected from being bitten within the inner chamber of the trap, while mosquitoes are lured to enter an outer chamber where they are trapped. The MosqTent previously collected an average of 3,000 anophelines/man-hour compared to 240 anophelines/man-hour for the human landing catch (HLC), thereby providing high numbers of human host-seeking mosquitoes while protecting the collector from mosquito bites. The MosqTent performed well by collecting a high number of specimens of Anopheles marajoara, a local vector and anthropophilic mosquito species present in high density, but not so well in collecting An.

Triflumuron Effects on the Physiology and Reproduction of Adult Females.

We evaluated the efficacy of the growth regulator triflumuron (TFM) in inducing mortality and disrupting both oviposition and egg hatching in adult females. TFM was administered via feeding, topically or by continuous contact with impregnated surfaces. Feeding resulted in mild biological effects compared with topical and impregnated surfaces.

Filling gaps on ivermectin knowledge: effects on the survival and reproduction of Anopheles aquasalis, a Latin American malaria vector.

Background: Strategies designed to advance towards malaria elimination rely on the detection and treatment of infections, rather than fever, and the interruption of malaria transmission between mosquitoes and humans. Mass drug administration with anti-malarials directed at eliminating parasites in blood, either to entire populations or targeting only those with malaria infections, are considered useful strategies to progress towards malaria elimination, but may be insufficient if applied on their own. These strategies assume a closer contact with populations, so incorporating a vector control intervention tool to those approaches could significantly enhance their efficacy.

Resistance Status to the Insecticides Temephos, Deltamethrin, and Diflubenzuron in Brazilian Aedes aegypti Populations.

Insecticides are still largely applied in public health to control disease vectors. In Brazil, organophosphates (OP) and pyrethroids (PY) are used against Aedes aegypti for years. Since 2009 Insect Growth Regulators (IGR) are also employed in the control of larvae.

Larval application of sodium channel homologous dsRNA restores pyrethroid insecticide susceptibility in a resistant adult mosquito population.

Background: Mosquitoes host and pass on to humans a variety of disease-causing pathogens such as infectious viruses and other parasitic microorganisms. The emergence and spread of insecticide resistance is threatening the effectiveness of current control measures for common mosquito vector borne diseases, such as malaria, dengue and Zika. Therefore, the emerging resistance to the widely used pyrethroid insecticides is an alarming problem for public health.

Spatial and temporal country-wide survey of temephos resistance in Brazilian populations of Aedes aegypti.

The organophosphate temephos has been the main insecticide used against larvae of the dengue and yellow fever mosquito (Aedes aegypti) in Brazil since the mid-1980s. Reports of resistance date back to 1995; however, no systematic reports of widespread temephos resistance have occurred to date. As resistance investigation is paramount for strategic decision-making by health officials, our objective here was to investigate the spatial and temporal spread of temephos resistance in Ae.

Phenotypic and genotypic profile of pyrethroid resistance in populations of the mosquito Aedes aegypti from Goiânia, Central West Brazil.

Introduction: The mosquito Aedes aegypti has evolved resistance to pyrethroid insecticides. The present study evaluated Ae. aegypti from Goiânia for the resistant phenotype and for mutations associated with resistance.

An overview of malaria transmission from the perspective of Amazon Anopheles vectors.

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Anopheles species have been conducted, but with only short-lived success or no success at all.

Surveillance of Aedes aegypti: comparison of house index with four alternative traps.

Introduction: The mosquito Aedes aegypti, vector of dengue, chikungunya and yellow fever viruses, is an important target of vector control programs in tropical countries. Most mosquito surveillance programs are still based on the traditional household larval surveys, despite the availability of new trapping devices. We report the results of a multicentric entomological survey using four types of traps, besides the larval survey, to compare the entomological indices generated by these different surveillance tools in terms of their sensitivity to detect mosquito density variation.

Hybrid sterility in crosses between two Brazilian sibling species of the Anopheles albitarsis complex.

Background: Complexes of cryptic species are common in several taxa and this is also the case in the Anopheles genus, a group including all known human malaria vectors. The Anopheles albitarsis complex comprises at least nine cryptic species, some of which are implicated as vectors of human malaria. Several different types of data have been generated for this species complex such as cytogenetics, alloenzymes, morphological and feeding behavioral, hybridization experiments, RAPD-PCR and RFLP and mitochondrial and nuclear markers.

Discrepancies between Aedes aegypti identification in the field and in the laboratory after collection with a sticky trap.

Currently, sticky traps are regularly employed to assist in the surveillance of Aedes aegypti infestation. We tested two alternative procedures for specimen identification performed by local health agents: directly in the field, as recommended by certain manufacturers, or after transportation to the laboratory. A total of 384 sticky traps (MosquiTRAP) were monitored monthly during one year in four geographically representative Brazilian municipalities.

Is there an efficient trap or collection method for sampling Anopheles darlingi and other malaria vectors that can describe the essential parameters affecting transmission dynamics as effectively as human landing catches? - A Review.

Distribution, abundance, feeding behaviour, host preference, parity status and human-biting and infection rates are among the medical entomological parameters evaluated when determining the vector capacity of mosquito species. To evaluate these parameters, mosquitoes must be collected using an appropriate method. Malaria is primarily transmitted by anthropophilic and synanthropic anophelines.

Effects of insemination and blood-feeding on locomotor activity of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) females under laboratory conditions.

Background: Dengue is an arbovirus disease transmitted by two Aedes mosquitoes: Ae. aegypti and Ae. albopictus.

Undesirable consequences of insecticide resistance following Aedes aegypti control activities due to a dengue outbreak.

Background: During a dengue outbreak with co-circulation of DENV-1 and -2 in the city of Boa Vista, one patient was diagnosed with DENV-4, a serotype supposed absent from Brazil for almost 30 years. The re-emergence of DENV-4 triggered the intensification of mechanical and chemical Aedes aegypti control activities in order to reduce vector density and avoid DENV-4 dissemination throughout the country.

Methods/principal Findings: Vector control activities consisted of (a) source reduction, (b) application of diflubenzuron against larvae and (c) vehicle-mounted space spraying of 2% deltamethrin to eliminate adults.

Evidence for gene duplication in the voltage-gated sodium channel gene of Aedes aegypti.

Background And Objectives: Mutations in the voltage-gated sodium channel gene (NaV), known as kdr mutations, are associated with pyrethroid and DDT insecticide resistance in a number of species. In the mosquito dengue vector Aedes aegypti, besides kdr, other polymorphisms allowed grouping AaNaV sequences as type 'A' or 'B'. Here, we point a series of evidences that these polymorphisms are actually involved in a gene duplication event.

Circadian clock of Aedes aegypti: effects of blood-feeding, insemination and RNA interference.

Mosquitoes are the culprits of some of the most important vector borne diseases. A species' potential as a vector is directly dependent on their pattern of behaviour, which is known to change according to the female's physiological status such as whether the female is virgin/mated and unfed/blood-fed. However, the molecular mechanism triggered by and/or responsible for such modulations in behaviour is poorly understood.

Distribution and dissemination of the Val1016Ile and Phe1534Cys Kdr mutations in Aedes aegypti Brazilian natural populations.

Background: The chemical control of the mosquito Aedes aegypti, the major vector of dengue, is being seriously threatened due to the development of pyrethroid resistance. Substitutions in the 1016 and 1534 sites of the voltage gated sodium channel (AaNaV), commonly known as kdr mutations, confer the mosquito with knockdown resistance. Our aim was to evaluate the allelic composition of natural populations of Brazilian Ae.

Experimental Plasmodium vivax infection of key Anopheles species from the Brazilian Amazon.

Background: Anopheles darlingi is the major malaria vector in countries located in the Amazon region. Anopheles aquasalis and Anopheles albitarsis s.l.

Assessing the effects of Aedes aegypti kdr mutations on pyrethroid resistance and its fitness cost.

Pyrethroids are the most used insecticide class worldwide. They target the voltage gated sodium channel (NaV), inducing the knockdown effect. In Aedes aegypti, the main dengue vector, the AaNaV substitutions Val1016Ile and Phe1534Cys are the most important knockdown resistance (kdr) mutations.

Effect of triflumuron, a chitin synthesis inhibitor, on Aedes aegypti, Aedes albopictus and Culex quinquefasciatus under laboratory conditions.

Background: Resistance to traditional insecticides represents a threat to the control of disease vectors. The insect growth regulators (IGR) are a potential alternative to control mosquitoes, including resistant populations. The chitin synthesis inhibitors (CSI) are IGRs, which interfere with the insect molting process and represent one major class of compounds against Aedes aegypti populations resistant to the larvicide organophosphate temephos.

The role of reactive oxygen species in Anopheles aquasalis response to Plasmodium vivax infection.

Malaria affects millions of people worldwide and hundreds of thousands of people each year in Brazil. The mosquito Anopheles aquasalis is an important vector of Plasmodium vivax, the main human malaria parasite in the Americas. Reactive oxygen species (ROS) have been shown to have a role in insect innate immune responses as a potent pathogen-killing agent.

Analysis of cycle gene expression in Aedes aegypti brains by in situ hybridization.

Even though the blood-sucking mosquito Aedes aegypti is one of the most important disease vectors, relatively little is known about the molecular mechanisms underlying processes involved in the temporal pattern of its activity and host seeking behavior. In this study, we analyzed the expression of the cycle (cyc) gene, one of the core components of the circadian clock, in Ae. aegypti brains by in situ hybridization at two different time points in light-dark conditions and compared the results with those obtained using a quantitative PCR assay (qPCR).

The efficacy of a chitin synthesis inhibitor against field populations of organophosphate-resistant Aedes aegypti in Brazil.

The mosquito Aedes aegypti is the main focus of dengue control campaigns. Because of widespread resistance against conventional chemical insecticides, chitin synthesis inhibitors (CSIs) are considered control alternatives. We evaluated the resistance status of four Brazilian Ae.

Effect of insecticide resistance on development, longevity and reproduction of field or laboratory selected Aedes aegypti populations.

Aedes aegypti dispersion is the major reason for the increase in dengue transmission in South America. In Brazil, control of this mosquito strongly relies on the use of pyrethroids and organophosphates against adults and larvae, respectively. In consequence, many Ae.