OBJECTIVE: To evaluate the residual effect of pyrethroids on the mortality rates of Anopheles in order to check their efficacy in indoor residual spraying in the Amazon Region, Brazil. METHODS: The study was conducted in public housing unities in the city of Belem, Northern Brazil, in 2003. Twelve houses were randomly chosen, three in each of the four established areas. Pyrethroids cypermethrin wettable powder, deltamethrin suspension concentrate, lambda-cyhalothrin wettable powder, and etofenprox wettable powder, were sprayed on the indoor wall […]

The following insecticides were mixed with industrialized dog food: Phoxim, Chlorphoxim, Themephos (Abate), Decamethrin, Lindane, and DDT. The insecticidal effect in the blood was tested with Triatoma infestans nymphs and adults. Positive results were obtained with Phoxim and Themephos. Chlorphoxim and Lindane at efficient levels became unpalatable. Decamethrin and DDT had no lethal effect upon the insects at the levels of concentration tolerated by the dogs.

The sensitivity of the adult house mosquito Culex quinquefasciatus to 5 chemical insecticides was evaluated under laboratory condictions, based on the Median Lethal Time (LT50) criterion. The organophosphorous Malathion and four pyrethroids: Bifenthrin, Deltamethrin, Esfenvalerate and Alfamethrin were utilized. An easy and efficient technique was suggested for the testing of one-day-old adults, including five repetitions for each treatment. The results revealed the full adequacy of this method for routine use. Further, no resistance to the 5 chemical compounds was detected […]

OBJECTIVE: To examine the peripheral auditory disorders in a group of workers exposed to organophosphate and pyrethroid insecticides, used in vector control campaigns. METHODS: The prevalence study examined a population of 98 individuals who sprayed insecticides in campaigns for the prevention of Dengue, Chagas disease and Yellow fever. The sampling approach was finalistic, and included the workers in a health district of Pernambuco, during the year 2000. A questionnaire was used to collect data on occupational and non-occupational risks, safety […]

OBJECTIVE: To estimate the degree of internal exposure to organochlorine pesticides (persistent organic pollutants, POP) among inhabitants of an open-air dump. METHODS: This was an observational study with simultaneous measurement and control, in which the criterion for subjects was that they dwelled in an area contaminated by POP and the effect of such contamination was the concentration of such substances into the blood. The study population consisted of 238 people living on an open-air dump in Pilões, in the municipality […]

OBJECTIVE: To evaluate the susceptibility to chemical insecticides of Culex quinquefasciatus and Aedes aegypt larvae from areas subjected to control treatments or not. METHODS: Bioassays for diagnostic concentration and multiple concentration were performed for organophosphate and pyrethroid insecticides according to World Health Organization parameters. The susceptibility was assessed for mosquito larvae collected from an area not subjected to chemical control (Campinas, State of São Paulo, SP) and from other areas (Campo Grande, Mato Grosso do Sul, MS, and Cuiabá, Mato […]

Three organophosphorus compounds- malathion, folithion and temephos- and two synthetic pyrethroids- alphamethrin and deltamethrin- were used for monitoring the susceptibility status of larvae and adults of six vector mosquitoe species: Culex quinquefasciatus (Filariasis) and Aedes albopictus (Dengue) (both laboratory and field strains); laboratory strains of Aedes aegypti (Dengue), Anopheles slephensi and Anopheles culicifacies (Malaria), and Culex tritaeniorhynchus (Japanese encephalitis) in India. From the LC50 values obtained for these insecticides, it was found that all mosquito species including the field strains […]

OBJECTIVE: Although insecticides are widely used in many countries, few studies of their use in households have been conducted. This study was carried out to describe the household use of insecticides according to per capita income. METHODS: From October 1999 to January 2000, questionnaires on the use of household insecticides were applied to 2,039 households in the urban area of Pelotas, Brazil. Data was collected on income, use of insecticides in the 12 months prior to the interview, product type […]

The population of Culex quinquefasciatus breeding in the Pinheiros River (S. Paulo, Brazil) has been controlled with organophosphates since 1980. However, the biting has constituted a continual nuisance to the human population who live in the vicinity of the river. The occurrence of insecticide resistance to at least two organophosphates and one carbamate (malathion, fenitrothion and propoxur, respectively) to this insect population is reported. The results show the need to develop an insecticide management program. The suscetibility to permethrin (pyretroid) […]

An alternative vector control method, using lambda-cyhalothrin impregnated wide-mesh gauze covering openings in the walls of the houses was developed in an area in the Eastern part of the interior of Suriname. Experimental hut observations showed that Anopheles darlingi greatly reduced their biting activity (99-100%) during the first 5 months after impregnation. A model assay showed high mortality both of mosquitoes repelled by the gauze as well as of those that succeeded in getting through it. A field application test […]