Green synthesis of silver nanoparticles derived from algae and their larvicidal properties to control .

Mosquito vectors such as . are responsible for the transmission of arboviruses that have a major impact on public health. Therefore, it is necessary to search for ways to control these insects, avoiding the use of conventional chemical insecticides that are proven to be toxic to nature.

Mapping indoor resting behavior reveals a preference vulnerable to householder-led vector control.

Many mosquito vectors rest inside human habitations, a behavioral trait that is exploited for vector control by indoor residual spraying (IRS) of interior walls with insecticide. Although IRS and its refined version targeted IRS are very effective against , they are expensive and logistically challenging to deliver in densely populated urban areas where outbreaks of dengue and other arboviruses are the greatest challenge. In experiments in Recife, Brazil, we set out to quantify the indoor resting behavior of at a level beyond that previously reported.

Double BR-OVT: a new trap model for collecting eggs and adult mosquitoes from Culex quinquefasciatus and Aedes spp.

The circulation of arboviruses throughout the world and the maintenance of lymphatic filariasis endemicity in tropical countries, combined with the lack of vaccines and specific treatments, highlight the importance of reducing the populations of mosquitoes involved in the transmission of these pathogens, Aedes aegypti and Culex quinquefasciatus. To contribute to the development of new strategies for monitoring and controlling these culicids, we evaluated the performance of the Double BR-OVT trap individually and in pairs, in the field. After 18 months, the Double BR-OVT traps captured a mean of 3.

Infestation of an endemic arbovirus area by sympatric populations of Aedes aegypti and Aedes albopictus in Brazil.

BACKGROUND Aedes aegypti and Aedes albopictus are the most important arbovirus vectors in the world. OBJECTIVES This study aimed to investigate and compare the infestation pattern of these species in a neighbourhood of Recife, Brazil, endemic for arboviruses in 2005 (T1) and 2013 (T2). METHODS Infestation, distribution and relative abundance of these sympatric species were recorded by egg collection using a network of 59 sentinel ovitraps (s-ovt) at fixed sampling stations for 12 months in T1 and T2.

A popular Indian clove-based mosquito repellent is less effective against Culex quinquefasciatus and Aedes aegypti than DEET.

Insect repellents are widely used as the first line of defense against mosquito bites and transmission of disease-causing agents. However, the cost of daily applications of even the most affordable and the gold standard of insect repellents, DEET, is still high for low-income populations where repellents are needed the most. An Indian clove-based homemade recipe has been presented as a panacea.

Conspecific and allospecific larval extracts entice mosquitoes to lay eggs and may be used in attract-and-kill control strategy.

One of the strategies of integrated vector management is to lure gravid mosquitoes for surveillance purposes or to entice them to lay eggs in water containing toxins that kill the offspring (attract-and-kill or trap-and-kill). Typically, the major challenge of this approach is the development of a lure that stimulates oviposition plus a toxin with no deterrent effect. Bacillus thuringiensis var.

Development of an urban molecular xenomonitoring system for lymphatic filariasis in the Recife Metropolitan Region, Brazil.

Introduction: Molecular xenomonitoring (MX)-pathogen detection in the mosquito rather than human-is a promising tool for lymphatic filariasis (LF) surveillance. In the Recife Metropolitan Region (RMR), the last LF focus in Brazil, Culex quinquefasciatus mosquitoes have been implicated in transmitting Wuchereria bancrofti parasites. This paper presents findings on the ideal mosquito collection method, mosquito dispersion, W.

Field evaluation of sticky BR-OVT traps to collect culicids eggs and adult mosquitoes inside houses.

Introduction: Culex quinquefasciatus is a mosquito of importance to public health, as it represents a real and/or potential risk for the transmission of pathogens to humans, such as some arthropod-borne viruses and nematodes that cause filariasis. In Brazil, three municipalities in the Metropolitan Region of Recife (RMR) that are endemic for lymphatic filariasis conducted control actions targeting this vector. With the goal of contributing novel C.

An unsettling explanation for the failure of skatole-baited ovitraps to capture Culex mosquitoes.

Culex mosquitoes are primarily found in temperate and tropical regions worldwide where they play a crucial role as main vectors of filarial worms and arboviruses. In Recife, a northeast city in Brazil, high densities of Culex quinquefasciatus are often found in association with human populated areas. In marked contrast to another part of the city, field tests conducted in the neighborhood of Sítio dos Pintos showed that trapping of mosquitoes in skatole-baited ovitraps did not differ significantly from captures in control (water) traps.

Insecticide susceptibility of Aedes albopictus and Ae. aegypti from Brazil and the Swiss-Italian border region.

Background: Aedes aegypti and Ae. albopictus are two highly invasive mosquito species, both vectors of several viruses, including dengue, chikungunya and Zika. While Ae.

Does Zika virus infection affect mosquito response to repellents?

The World Health Organization (WHO) recommends that people travelling to or living in areas with Zika virus (ZIKV) outbreaks or epidemics adopt prophylactic measures to reduce or eliminate mosquito bites, including the use of insect repellents. It is, however, unknown whether repellents are effective against ZIKV-infected mosquitoes, in part because of the ethical concerns related to exposing a human subject's arm to infected mosquitoes in the standard arm-in-cage assay. We used a previously developed, human subject-free behavioural assay, which mimics a human subject to evaluate the top two recommended insect repellents.

Immature Aedes mosquitoes colonize Culex quinquefasciatus breeding sites in neighborhoods in the municipality of Olinda, State of Pernambuco.

Introduction: The present study shows the colonization of Aedes mosquitoes in breeding sites specific for Culex quinquefasciatus in neighborhoods in the municipality of Olinda.

Methods: Samples were collected between May 2011 and June 2012 from breeding sites positive for Cx. quinquefasciatus by using a ladle and manual suction pump.

Characterization of the spatial and temporal dynamics of the dengue vector population established in urban areas of Fernando de Noronha, a Brazilian oceanic island.

Aedes aegypti has played a major role in the dramatic expansion of dengue worldwide. The failure of control programs in reducing the rhythm of global dengue expansion through vector control suggests the need for studies to support more appropriated control strategies. We report here the results of a longitudinal study on Ae.

RNAi-based demonstration of direct link between specific odorant receptors and mosquito oviposition behavior.

The Southern house mosquito, Culex quinquefasciatus--a vector of West Nile virus--is equipped with 130 odorant receptors (ORs), which enable young females to locate plants and blood-meal sources and older females to find suitable sites for oviposition. In our attempts to de-orphanize ORs expressed in female antennae, we identified CquiOR37 and CquiOR99, which were narrowly tuned to two phenolic compounds, 4-methylphenol and 4-ethylphenol. When tested in the Xenopus oocyte recording system the observed EC50s for 4-methylphenol and 4-ethylphenol were 6.

Sustained reduction of the dengue vector population resulting from an integrated control strategy applied in two Brazilian cities.

Aedes aegypti has developed evolution-driven adaptations for surviving in the domestic human habitat. Several trap models have been designed considering these strategies and tested for monitoring this efficient vector of Dengue. Here, we report a real-scale evaluation of a system for monitoring and controlling mosquito populations based on egg sampling coupled with geographic information systems technology.

Residential characteristics aggravating infestation by Culex quinquefasciatus in a region of Northeastern Brazil.

Objective: Analyse how basic sanitation conditions, water supply and housing conditions affect the concentration of Culex quinquefasciatus

Methods: Populations of C. quinquefasciatus in 61 houses in the municipality of Olinda, PE, were monitored between October 2009 and October 2010. Observations were carried out in homes without the presence of preferred breeding sites in order to identify characteristics that may be aggravating factors for the development of the mosquito.

Monitoring temporal fluctuations of Culex quinquefasciatus using oviposition traps containing attractant and larvicide in an urban environment in Recife, Brazil.

The use of attractants and larvicides in oviposition traps is of practical interest for the surveillance and control of urban mosquitoes. In addition to increasing the safety of the traps, this combination is essential for an attract-and-kill control strategy based on trapping mosquito eggs. The combination of Bacillus thuringiensis var.

Evaluation of an oviposition-stimulating kairomone for the yellow fever mosquito, Aedes aegypti, in Recife, Brazil.

A synthetic mixture of an oviposition-stimulating kairomone for the yellow fever mosquito, Aedes aegypti, comprising of 83% tetradecanoic acid, 16% nonanoic acid and 1% tetradecanoic acid methyl ester (NTT, in short) was tested in a dengue endemic area in Recife, Brazil. Gravid female mosquitoes confined to a cage under semi-field conditions deposited significantly higher numbers of eggs in traps baited with NTT at doses ranging from 0.6 to 600 ng/microl than in control (water) traps.

Culex mosquitoes (Diptera: Culicidae) egg laying in traps loaded with Bacillus thuringiensis variety israelensis and baited with skatole.

The Southern house mosquito, Culex quinquefasciatus, is an important human health pest as a vector of several pathogens, including agents of lymphatic filariasis and arboviruses like West Nile virus. We conducted preliminary experiments in Recife, Brazil, to explore applications of Culex oviposition attractants in combination with Bacillus thuringiensis variety israelensis (Bti) in an attract-and-kill approach. Simple, cost-effective oviposition traps, BR-OVT, loaded with Bti and baited with or without attractant, were deployed in 10 homes for 30 d in 2 consecutive yr.

Reverse and conventional chemical ecology approaches for the development of oviposition attractants for Culex mosquitoes.

Synthetic mosquito oviposition attractants are sorely needed for surveillance and control programs for Culex species, which are major vectors of pathogens causing various human diseases, including filariasis, encephalitis, and West Nile encephalomyelitis. We employed novel and conventional chemical ecology approaches to identify potential attractants, which were demonstrated in field tests to be effective for monitoring populations of Cx. p.

Laboratory and field evaluation of an oviposition trap for Culex quinquefasciatus (Diptera: Culicidae).

An ovitrap (BR-OVT) based on physical and chemical stimuli for attracting gravid Culex quinquefasciatus (Diptera: Culicidae) females was developed and evaluated under laboratory and field conditions. Attractants were assayed using alternative chamber bioassays prior to being used in the BR-OVT oviposition trap. A significant preference of gravid females for sites containing conspecific egg rafts was observed, as a response to the natural oviposition pheromone, as well as for sites treated with the synthetic pheromone erythro-6-acetoxy-5-hexadecanolide.