Background: Using insecticides is considered as a temporary and rapid method for interrupting the disease transmission through disease vectors such as dengue. The insecticide Fendona, when absorbed into bed nets, is slowly released and rapidly knocks out, kills or repels mosquitoes as they come into contact with the bed net. Objectives: To evaluate the effectiveness of the Interceptor bed net (a unique textile-finishing product developed by BASF, Singapore PTE. LTD, that were coated with the Fendona insecticide) on controlling disease vector Aedes aegypti. Subjects and method: An experimental trial was carried out at the National Institute of Hygiene and Epidemiology and in the field of Hien Giang commune, Thuong Tin district, Ha Tay province. The changes of efficacy of Interceptor bed net were compared by not washing with washing at the different levels. Results: The unwashed bed nets can knock out and kill Aedes aegypti mosquitoes by 50% after 20 minutes of exposure on every trial. About 90-100% of total mosquitoes were killed after the first 30 minutes of exposure. Bed net\u2019s efficacy remains until 24 hours of the trial. The recovery rate of the mosquito is 0%. The same results were also observed after 90 days, 36 days and 18 days of bed nets being laundered. However, after 9 day of washing, the bed nets can only kill the mosquitoes up to about 90-95% of the total after the first 30 minutes of exposure. It also reached 100% of killing after 24 hours. However, its efficacy was conversely reduced with regard to the increase of laundry times. Conclusion: The density of adult mosquitoes and larvae for Aedes aegypti was significantly reduced in the intervention areas, even at zero level in comparison to the control sites. The insecticide had no side-effect or any stimulation to users, community, poultry, cattle and environment in the intervention sites.
Interceptor bednet ; disease vector ; Aedes aegypti

reslin ; Upper case are ; Aedes aegypti ; bioresmethrin

Laboratory-bred females of Culex quinquefasciatus, Aedes aegypti and Aedes albopictus from the insectarium, Unit of Medical Entomology, Institute for Medical Research were used in the experiment. The late third stage of the F0 larvae which survived the high selection pressure of malathion, permethrin and temephos were reared and colonies were established from adults that emerged. Cx. quinquefasciatus larvae were subjected to selection by malathion and permethrin for 40 generations, Ae. aegypti larvae to malathion, permethrin and temephos for 32 generations and Ae. albopictus larvae were selected against malathion and permethrin for 32 generations and 20 generations against temephos. The rate of resistance development was measured by LC50 value. Cx. quinquefasciatus larvae developed higher resistance to malathion and permethrin compared to Ae. aegypti and Ae. albopictus. On the whole, permethrin resistance developed at a faster rate than malathion and temephos.
Permethrin ; Malathion ; Cancer resistance to treatment ; Aedes aegypti ; Aedes albopictus

Background: Currently, tracking, monitoring insecticide resistance of mosquitoes transmitting disease is an urgent need.\r\n', u'Objectives: To evaluate resistance to insecticide of three mosquito species: Aedes Aegypti, Culex quinquefasciatus and culex tritaenyorhynchus in Ha Noi\r\n', u'Subject and method: Aedes Aegypti, Culex quinquefasciatus culex tritaenyorhynchus mosquito species was collected from some districts of Ha Noi city. These mosquito species was tested sensitivity with 4 insecticides: permethrin 0.75%, lambda-cyhalothrin 0.05%, alpha-cypermethrin 30mg/m2 and DDT 4.0%.\r\n', u'Results: Three main vectors of Dengue fever, Japanese Encephalic and Filariasis mosquitoes were found in a very high density in some areas of Ha Noi City. Aedes aegypti mosquitoes in the districts of Thanh Xuan (TX), Dong Da (DD) and Hoang Mai (HM) was found highly resistant to permethrin, alpha - cypermethrin, lambda - cyhalothrin and DDT with the mortalities rates of 51 % (TX) and 59%(DD); 70%(HM); 90%, 82% and 96%; 74%, 54% and 59%; 1 %, 8% and 32%, respectively. \r\n', u'Culex tritaenyorhynchus was found also highly resistant to permethrin with the mortality rate of 29%, alphacypermethrin - 18%, lambdacyhalothrin - only 3% and DDT x36%. Culex quinquefasciatus was found also highly resistant to those insecticides. \r\n', u'Conclusion: Other insecticides should choose to replace the chemicals used in this experiment to control, kill mosquitoes when epidemics occur.\r\n', u'
Insecticides ; resistance ; Aedes Aegypti ; Culex quinquefasciatus ; culex tritaenyorhynchus

Using standard WHO methodology, this study investigated the susceptibility of 4(th) instar Aedes aegypti (L) and Culex annulirostris (Skuse) larvae to three extracts from Callitris glaucophylla (J. Thompson & L. Johnson) (1: steam distillation extract, 2: liquefied refrigerant gas extract, and 3: methanol reflux extract), lambda-cyhalothrin (a synthetic pyrethroid insecticide) and fenitrothion (an organophosphorous insecticide). Cx. annulirostris was significantly more susceptible than Ae. aegypti to all tested chemicals except lambda-cyhalothrin. Responses to the three C. glaucophylla extracts were exceptional for a botanical compound: Cx. annulirostris (LC(50) = 0.23, 9.53 and 38.95 mg/L) and Ae. aegypti (LC(50) = 0.69, 5.21 and 306.43 mg/L). Both Cx. annulirostris and Ae. aegypti larvae were significantly more susceptible to lambda-cyhalothrin (LC(50) = 0.00013 and 0.00016 mg/L) than fenitrothion (LC(50) = 0.0009 and 0.004 mg/L). As expected, the pyrethroid and organophosphorous insecticides were far more potent than the crude C. glaucophylla extracts. The steam distilled extract was fractionated and the major components guaiol and citronellic acid were identified and tested. Activities for these major components were lower than observed for the distillate. Minor components include lactones such as eldanolide, and future testing of minor components may indicate the active component.
mg/L ; Aedes aegypti ; Culex annulirostris ; cyhalothrin ; Insecticides

The resistance to various insecticides from 4 major groups (organochlorine, organophosphate, carbamate and pyrethroid) was investigated in a field strain of Culex quinquefasciatus from Baan Suan community, Nonthaburi province, Thailand by using a standard World Health Organization susceptibility test. The Baan Suan strain was completely resistant to DDT and highly resistant to deltamethrin, permethrin, fenitrothion and propoxur but this strain was still found to be highly susceptible to malathion. This strain displayed high resistance to cypermethrin since the result revealed that the resistance ratio of the 50% lethal concentration value (RR50) between the field and the laboratory strains (NIH strain) was 16. The study indicated that mosquitoes were resistant to almost all insecticide tested except malathion and this should be an alternative for Cx. quinquefasciatus control in this area. Moreover, Aedes aegypti, which is a main dengue vector in Baan Suan community was also tested with deltamethrin, permethrin and fenitrothion. The results showed that dengue mosquitoes are clearly resistant to permethrin and tolerant to deltamethrin, but was 100% susceptible to fenitrothion. The cause of insecticide resistance in Cx. quinquefasciatus may be due to the continuous use of insecticide for dengue vector control programme in Baan Suan community.
Insecticides ; Cancer resistance to treatment ; Aedes aegypti ; Culex quinquefasciatus ; Permethrin

The insecticide susceptibility of Aedes aegypti larvae and adults from four areas of Ratchaburi Province, Thailand was investigated using World Health Organization standard procedures. The larvae of Ae. aegypti in all areas were found to be susceptible to temephos. The strain with the highest level of temephos resistance was subjected to temephos selection. The resistance ratios increased to 2.74-fold from their parental non selected strain after 5 generations of selection. For the adult of Ae. aegypti, the study was conducted to determine the effects of 0.75 % permethrin and 0.05 % deltamethrin impregnated paper selection on the strain having the highest with the highest LT50 level. The results showed the increase in the LT50 to 7.46 and 1.18-fold after the third selected generation with 0.75 % permethrin and 0.05 % deltamethrin respectively. Mortality rates after exposing adults to discriminating concentrations showed that field populations in Ratchaburi Province were resistant to permethrin and deltamethrin. Alternative non-chemical measures need to be used in new of the emergence of resistance in the mosquito population.
Cancer resistance to treatment ; Selection (Genetics) ; Aedes aegypti ; Permethrin ; decamethrin