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.

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.

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.

Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas.

The geographical distribution of Aedes albopictus in Brazil was updated according to the data recorded across the country over the last eight years. Countrywide house indexes (HI) for Ae. albopictus in urban and suburban areas were described for the first time using a sample of Brazilian municipalities.

Insecticide resistance mechanisms of Brazilian Aedes aegypti populations from 2001 to 2004.

In Brazil, Aedes aegypti resistance to temephos, used since 1967, was detected in several municipalities in 2000. Organophosphates were substituted by pyrethroids against adults and, in some localities, by Bti against larvae. However, high temephos resistance ratios were still detected between 2001 and 2004.

Effectiveness of methoprene, an insect growth regulator, against temephos-resistant Aedes aegypti populations from different Brazilian localities, under laboratory conditions.

The susceptibility of Aedes aegypti (L.) larvae from several Brazilian populations to the juvenile hormone analog methoprene and the organophosphate insecticide temephos were investigated. Populations from Natal (northeastern region), Macapá (northern region), and Jardim América, Rio de Janeiro (southeastern region) are temephos-resistant (RR90 = 24.

Evaluation of methoprene effect on Aedes aegypti (Diptera: Culicidae) development in laboratory conditions.

Several Brazilian Aedes aegypti populations are resistant to the larvicidae temephos. Methoprene, that inhibits adult emergence, is one of the alternatives envisaged by the Brazilian Dengue Control Program (PNCD). However, at Brazil vector infestation rates are measured through larvae indexes and it has been claimed that methoprene use in the field could face operational problems.

Aedes aegypti resistance to temephos during 2001 in several municipalities in the states of Rio de Janeiro, Sergipe, and Alagoas, Brazil.

For more than 30 years temephos, an organophosphate insecticide, has been the sole larvicide used in Brazil in the control of Aedes aegypti. Organophosphates were also used for adult control, being replaced by pyrethroids since 1999. In this same year the Brazilian Health Foundation started the coordination of the Ae.

Resistance of Aedes aegypti to organophosphates in several municipalities in the State of Rio de Janeiro and Espírito Santo, Brazil.

Chemical insecticides have been widely used in Brazil for several years. This exposes mosquito populations to an intense selection pressure for resistance to insecticides. In 1999, the Brazilian National Health Foundation started the first program designed to monitor the resistance of Aedes aegypti to insecticides.