Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Temefos”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2005

Effectiveness of dengue control practices in household water containers in Northeast Thailand.

OBJECTIVE: To investigate the influence of larval control methods (using temephos, keeping fish and covering containers with lids), water use and weekly cleaning of containers on the presence of Aedes aegypti larvae in water-storage containers in rural and urban households in Khon Kaen province. METHOD: Cross-sectional questionnaire survey and larval survey covered 966 households and 5821 containers were inspected. RESULT: In rural and urban areas larval control was patchy and often ineffective. Consequently, the mosquito indices exceed the target indices for dengue control with the Breteau Indices of 201 and 113, and Container Indices of 25 and 28 in rural and urban areas, respectively. The containers most frequently infested with larvae were rectangular cement containers storing water for bathing (rural: 37.2%; urban: 35%) and flushing the toilets (rural: 35.7%; urban: 34.3%). Keeping fish [adjusted odds ratio (AOR): 0.08-0.16] was the most effective methods of control. Correctly covering containers with lids was similarly effective (AOR: 0.10-0.25) when used on jars for storing drinking water. However, frequent use of containers reduced the effectiveness of lids. Temephos was effective only in dragon jars in urban areas (AOR: 0.46) where a standard package of temephos were available. Weekly cleaning of containers was an effective method for larval control in most types of containers. A combination of control methods increased effectiveness. CONCLUSION: This study highlights the complex interaction of household water use and larval control practices as well as the importance of determining the most effective control measures compatible with water practices for implementing control promotion.

Aedes↗
PubMed1991

Susceptibility of Aedes aegypti larvae to temephos and Bacillus thuringiensis var israelensis in integrated control.

The susceptibility of field collected Aedes aegypti larvae was evaluated in terms of median lethal time (LT50) and final mortality, when treated with temephos, Bacillus thuringiensis var israelensis as well as mixtures of these two agents. Third instar larvae were shown to be more susceptible than early and late fourth instar ones to the entomopathogen. Survival of some individuals when exposed to temephos suggest possible resistance. Temporal synergism in early fourth instar larvae was detected when they were exposed to mixtures of Bti-temephos. The possibility of this integrated treatment is commented on.

Aedes↗
PubMed1991

[Susceptibility of populations of Simulium (Chirostilbia) pertinax Kollar, 1832 (Culicomorpha, Simuliidae) to eemephos and to Bacillus thuringiensis var. israelensis-based formulation].

The use of wooden troughs on stream beds, artificially colonized by blackfly larvae, is proposed for larvicide evaluations. Mortality was recorded 3 or 4 hours after treatment. Larval susceptibility was also evaluated utilizing the LT50 criterion. In there field assays Simulium (C.) pertinax populations from the litoral of S. Paulo and Rio de Janeiro States were shown to be resistant to temephos, even when subjected to high concentrations. Vectobac 12 AS, a Bacillus thuringiensis var. israelensis product, was shown to be more potent against late instar larvae and efficient in concentrations higher than 7,200 ITU/l (10 min). The LT50 to 3,744 ITU/l (10 min) was calculated as 70.9 min.

Animals↗
PubMed2001

[Larval susceptibility to chemical insecticides of two Aedes aegypti populations].

OBJECTIVE: Insect susceptibility has been one of the most important aspects to be monitored in public health programs for vector control. The purpose of the study is to assess the susceptibility to chemical insecticides of Aedes aegypti larvae in both areas under vector control and no vector control. METHODS: World Health Organization standard bioassays for diagnostic concentration and multiple concentrations were performed in mosquito larvae collected in an area under no vector control (Campinas, SP) and an area under vector chemical control (Campo Grande, MS), in Brazil. RESULTS: Potential resistance to a diagnostic concentration of temephos (DC=0.04 ppm) was registered for an Ae. aegypti larval population collected in Campinas. Multiple concentration tests confirmed the larvae resistance, with 24.5% of them surviving at the 0.0125 ppm concentration. Bioassays with the organophosphate fenitrothion (DC=0.08 ppm) and pyrethroid cypermethrin (DC=0.01 ppm) in the same population revealed their susceptibility to these agents. Bioassays carried out in an Ae. aegypti larval population collected in Campo Grande showed their susceptibility to temephos (DC=0.04 ppm) and cypermethrin (DC=0.01 ppm). LC50 and LC95 for cypermethrin (CE25), cyfluthrin (CE5), betacyfluthrin (SC1.25) and propoxur (CE20) were determined for Ae. aegypti. Using the Rockefeller standard strain values, ratios of resistance were estimated: 2.9, 2.2, 2.4 and 1.3 for LC50 and 3.5, 2.6, 3.9 and 1.3 for LC95, respectively. CONCLUSION: The findings reinforce the need for routinely monitoring pesticide efficacy as a very important step in vector control management programs.

Aedes↗
PubMed2004

[Susceptibility of Aedes aegypti larvae to the insecticide temephos in the Federal District, Brazil].

OBJECTIVE: To study the susceptibility status of Aedes aegypti to the organophosphate insecticide temephos. METHODS: Samples of Ae. aegypti larvae were obtained, using ovitraps, from eight cities of the Federal District, central Brazil, in 2000 and 2001. Larvae were submitted to the diagnostic dose of 0.012 mg/l temephos, as recommended by standard World Health Organization methodology. Field populations were tested in parallel with reference strains Rockefeller and DIVAL, from the Environmental Surveillance Directory (DIVAL) insectary. The concentration and purity of temephos solutions were verified by gas chromatography. Correlation calculations were performed using StatView - SAS Institute Inc., version 5. Student's t test was used for detecting differences in susceptibility, with significance levels of alpha=0.05. RESULTS: In 2000, Ae. aegypti larvae populations from Taguatinga, Guara, and Nucleo Bandeirante showed resistance to temephos, with mortality ranging from 54.1 to 63.4%. The populations from Gama, Planaltina, and Sobradinho showed altered levels of susceptibility (mortality ranging from 83.6 to 92.8%). The population from Ceilandia was the only susceptible one, with 98% mortality. In 2001, all populations tested were resistant (44.4 to 66.4% mortality). No significant correlation was found between the susceptibility of populations and the distance between the cities of origin, or the amount of insecticide applied in the years preceding the study. CONCLUSIONS: Ae. aegypti susceptibility to temephos is changing in the Federal District. It is essential to continue monitoring the resistance of this vector to insecticides in order to ensure the efficiency of programs aimed at vector control and at the protection of human health.

Aedes↗
PubMed2004

Control of Aedes aegypti with temephos in a Buenos Aires cemetery, Argentina.

The efficacy of a larvicide, temephos, for controlling Ae. aegypti was evaluated in a cemetery in Buenos Aires, Argentina. Breeding sites decreased from 18.4% in the first study period (Nov 1998 to May 1999, without temephos) to 2.2% in the second period (Nov 1999 to May 2000, two applications), and to 0.05% in the third one (Nov 2000 to May 2001, five applications). Ovitraps with eggs decreased from 17% in the first period to 5.8% in the second period, and to 2.9% in the third one. Results suggest that, in Buenos Aires, Ae. aegypti populations are highly susceptible to temephos. It is recommended to limit the use of temephos to prevent potential epidemics rather than for routine control.

Aedes↗
PubMedDate not supplied

[The residual effect of temephos on Aedes aegypti larvae].

One of the most used strategies for controlling Aedes aegypti is the use of the larvicide temephós (Abate). This larvicide has a prolonged residual effect which allows planning the focal treatments. This study aims to verify the duration of the larvicide residual effect stimulating a field situation. Plastic containers of one and five liters were treated with temephós and the residual effect was evaluated every 30 day after the treatment. Different residual effect was observed in the containers placed outside and inside the laboratory. The containers of one liter showed a longer residual effect than the five liters containers. The water salinity as well as the pH, during the test did not affect the larvicide effect.

Aedes↗
PubMedDate not supplied

Methods for field detection of resistance to temephos in simuliids. Larval esterase level and topical application of the insecticide to adults.

Two practical field methods for indirect detection of simuliid populations resistant to temephos are proposed. The first is based on high esterase activity in resistant larvae and involves adaptations of a filter paper test in which faintly stained spots indicate susceptible populations and strongly stained ones reveal populations resistant to temephos. The second is based on the resistance to the larvicide when adults are topically exposed, and involves the use of diagnostic doses obtained by the comparison between the LD50 for susceptible and resistant populations. The relevance of such methods is discussed in order to help resistance detection in Simulium pertinax Kollar control programmes.

Administration, Topical↗
PubMed2001

Chromosomal comparisons among and within populations of Simulium (Chirostilbia) pertinax (Diptera, Simuliidae).

Chromosomal studies were carried on six larval populations of Simulium (Chirostilbia) pertinax from different locations in Brazil. Larvae were collected in the states of Paraná, Rio Grande do Sul, Rio de Janeiro and São Paulo. Polytene chromosome map comparisons within and among populations showed no differences in banding pattern, except for some limited polymorphism (secondary NOR and four band polymorphisms). There were no chromosomal variations associated with the resistance or susceptibility of the larvae to temephos. The chromosomal homosequentiality found among the six populations suggests that S. pertinax may be a monomorphic species.

Animals↗
PubMed2003

Evaluation of the impact of Bacillus thuringiensis serovar israelensis and Temephos, used for the control of Simulium (Chirostilbia) pertinax Kollar, 1832 (Diptera, Simuliidae) on the associated entomofauna, Paraty, state of Rio de Janeiro, Brazil.

The study was set up to evaluate the impact of two commercial larvicide formulations, Bacillus thuringiensis serovar israelensis base (Bti) at 15 ppm/1 min and temephos at 0.03 ppm of active ingredient, used to control Simulium pertinax populations, on associated non-target entomofauna occupying the same breeding sites. The experiments were carried out on the Pedra Branca and Muricana rivers, on the slopes of Serra do Mar massif, municipality of Paraty, state of Rio de Janeiro, Brazil. Bti was applied to the river Pedra Branca and temephosto theriver Muricana. On both rivers, treatment and control sections were labeled as such, each one with two observation posts: slow moving water and fast water regions respectively. Artificial substrata was used to evaluate the abundance of associated entomofauna. Attached immature stages of arthropods were removed from both of its surfaces fortnightly. Were collected, from the two rivers, 28 477 specimens of the entomofauna associated with S. pertinax. The families Hydropsychidae, Chironomidae, Bactidae, Simuliidae, Blephariceridae and Megapodagrionidae were represented. These was an impact of temephos on the entomofauna associated with S. pertinax only in Simuliidae and Chironomidae, and to Bti only in Simuliidae. However, the reduction in their numbers was not statistically significant.

Animals↗
PubMed2003

Resistance of Aedes aegypti from the state of São Paulo, Brazil, to organophosphates insecticides.

Since the reintroduction of Aedes aegypti in the state of S o Paulo, in the middle of the 1980-decade, organophosphate insecticides are being used to control the dengue vector. In 1996, an annual program for monitoring the susceptibility of Ae. aegypti to the insecticides was implemented. Some of the results of this monitoring program are presented. Ae. aegypti populations from ten localities have been submitted to bioassays with the diagnostic dose of temephos and fenitrothion. Only two (Mar lia and Presidente Prudente) remain susceptible to both insecticides and one (Santos) exhibits true resistance. Ae. aegypti from the remaining localities showed an incipient altered susceptibility. Resistance ratios varied from 1.2 to 2.9 for temephos and from 1.5 to 3.2 to fenitrothion, indicating moderate levels of resistance. Biochemical assays did not detect alterations in the enzyme acetilcholinesterase, but indicated that resistance is associated with esterases.

Aedes↗
PubMed2004

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. aegypti Insecticide Resistance Monitoring Program. In the context of this program, our group was responsible for the detection of temephos resistance in a total of 12 municipalities in the states of Rio de Janeiro (RJ), Alagoas (AL), and Sergipe (SE) during 2001. In each municipality, a pool of mosquitoes collected from different districts was used, with the exception of Rio de Janeiro city, where eight districts have been separately evaluated. Exposure of larvae to the diagnostic dose of temephos revealed resistance in all localities examined, with mortality levels ranging from 4% (Pilares district, Rio de Janeiro, RJ) to 61.9% (Campos dos Goytacazes, RJ). Quantification of mortality showed resistance ratios from 6.1 (Aracaju, SE) to 16.8 (São Gonçalo, RJ and Penha district, Rio de Janeiro, RJ). The national dengue control program is presently using these data to subside insecticide resistance management.

Aedes↗
PubMedDate not supplied

[Insecticide resistance in Simulium populations (Diptera, Simuliidae)].

Populations of Simulium (Chirostilbia) pertinax Kollar, 1832 from Southern and Southeastern States of Brazil were analyzed for temephos susceptibility considering control historical information and possible resistance. In situ bioassays were carried out for populations from the states of Paraná (Tibaji and Rolândia), Rio de Janeiro (Muriqui) and São Paulo (Barra do Una, Ilhabela and Morungaba). The populations were characterized as susceptible (S) or resistant (R) by submitting larvae in the last instars to an operational concentration (0.1ppm a.i./10min) of temephos (Abate 500E) as diagnostic. The possible mechanisms for the organophosphorus resistance development are discussed considering old and new control strategies.

Animals↗
PubMedDate not supplied

Evaluation of the residual effect of temephos on Aedes aegypti (Diptera, Culicidae) larvae in artificial containers in Manaus, Amazonas State, Brazil.

Trial tests and container observations were conducted in households to verify the residual effect of temephos in Manaus, Amazonas State, Brazil. Three plastic buckets, three tin cans, and three tires filled with water from an artesian well and larvicide were used in the experiment, with twenty-five third-instar larvae, which remained exposed for 24h, followed by mortality readings. The same types of containers were selected from common households. Collection and counts followed by chemical treatment were carried out on the larvae that were found. Follow-up was performed weekly to verify recolonization by Aedes aegypti. The experiment showed 100% mortality in the plastic buckets until day 90, and 80% in the tin cans until day 30, decreasing from day 45 onwards. Mortality in the tires decreased to 35% in the first month. Household results showed 100% mortality for all containers after 24h and differentiated values in the subsequent readings. Larvae were observed on day 35 in a tin can and on day 21 in a gallon can. There was a large diversity of results in the tires, with recolonization observed from day 7 onwards.

Aedes↗
PubMed2000

Toxicity of insecticides for control of freshwater Culex annulirostris (Diptera: Culicidae) to the nontarget shrimp, Caradina indistincta (Decapoda: Atyidae).

Laboratory evaluations were conducted in southeastern Queensland, Australia, to determine the toxicities of two organophosphate compounds (temephos and pirimiphos-methyl), an insect growth regulator (s-methoprene), and an entomopathogenic bacterium (Bacillus thuringiensis variety israelensis de Barjac [B.t.i.]) to Culex annulirostris (Skuse), an Australian freshwater mosquito vector of arboviruses, and to Caradina indistincta Calman, a co-habiting nontarget shrimp species. S-methoprene and B.t.i. were safest for Cx. annulirostris control with lethal dose ratios (LC95 nontarget/LC95 target) of 3,300 and 846,000, respectively. In contrast, lethal dose ratios for temephos and pirimiphos-methyl were 0.05 and 0.00005, respectively, suggesting that they are environmentally unsuitable. Based on their high lethal dose ratios, s-methoprene and B.t.i. are recommended for control of larval Cx. annulirostris in Australian freshwater habitats.

Animals↗