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R K Razdan

Publications and source records attributed to R K Razdan.

122 records · Page 7Linked to original sources

Operational feasibility and efficacy of deltamethrin impregnated hessian curtains in comparison to HCH indoor residual spraying to control malaria in selected villages of District Ghaziabad (U.P.), India.

A study was carried out in selected villages of District Ghaziabad to evaluate the operational feasibility and efficacy of hessian curtains impregnated with deltamethrin@100 mg/m2 in comparison to indoor residual spraying of HCH@0.2 g/m2. The impregnation was carried out before onset of transmission and observations were continued up to two transmission periods. District Health Authorities have carried out HCH indoor residual spraying (IRS) as per schedule in the control village. Entomological evaluation revealed 87 per cent reduction of An. culicifacies up to six months in comparison to HCH indoor residual spraying. However, the reduction in densities of total mosquitoes was only 61.6 per cent. Follow-up studies revealed that the impact of deltamethrin impregnated curtains was diluted after 6-7 months. The results of bioassay tests revealed 100 per cent mortality up to 6-7 months. Epidemiological evaluation revealed 81.9 per cent reduction in total malaria cases as against 88.5 per cent with P. falciparum cases. Similar reduction was also observed when slide positivity rate (SPR), slide falciparum rate (SfR), cases/000 and Pf/000 were compared to corresponding village. Pilot studies are indicated to evaluate the relative efficacy of impregnated curtains, which is quite cheaper than conventional residual insecticide spraying (IRS).

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Operational feasibility and bio-efficacy of alphacypermethrin (Fendona) treated jute curtains to control urban malaria in a slum settlement of Delhi, India.

Operational feasibility and bio-efficacy of alphacypermethrin treated curtains was evaluated in slum settlements of Andrews Ganj, New Delhi. Jute curtains treated with alphacypermethrin @ 100 mg/m2 were fixed on windows, doors and eves before on set of transmission and evaluations were carried out for two years. Entomological evaluation revealed that jute curtains treated with alphacypermethrin in Slum-I resulted drastic reduction in daytime indoor resting mosquitoes such as An. stephensi, Ae. aegypti and Cx. quinquefasciatus. Similarly, malaria incidence also reduced in the treated curtain used area when compared to that of in untreated curtain and without curtain areas. Bioassay tests on An. stephensi and Cx. quinquefasciatus showed that alphacypermethrin could produce > 70 per cent mortality up to six months in case of An. stephensi--a principal urban malaria vector and hence two rounds of treatment are sufficient in an year to protect inhabitants from malaria. The study indicates alphacypermethrin treated curtains could curtail malaria transmission in slum settlements and is operationally feasible in small houses and is also cost-effective.

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Bio-efficacy and operational feasibility of alphacypermethrin (Fendona) impregnated mosquito nets to control rural malaria in northern India.

Bio-efficacy and operational feasibility of alphacypermethrin treated nets was evaluated in certain villages of District Ghaziabad (U.P.). Results revealed that poly-filament nylon nets treated with alphacypermethrin suspension concentrate (g/l) formulation @ 25 mg/m2 has shown repellent action (26.5 +/- 8.1), excito repellent action (93.7 +/- 8.1) and killing action (100%) against An. culicifacies landed on treated nets. Significant reduction in indoor resting density of An. culicifacies in human dwellings was also observed in treated nets village (p < 0.05). Instant killing action of treated nets did provide complete protection to inhabitants sleeping inside the net from An. culicifacies bites. The persistent use of nets by the inhabitants has also resulted significant reduction in malaria cases (p < 0.05). It was interesting to note that not even a single case of falciparum malaria was observed after distribution of treated nets in spite of the fact that at no point of time cent per cent compliance of net usage was observed during the study period. Bio-assay tests revealed that treated nets can produce up to 70% mortality in An. culicifacies for about 22 weeks and as such only one treatment with insecticide is required in a year in seasonal transmission area to protect from malaria. The study also revealed that treated nets can be stored at room temperature for about 10 months without loosing their efficacy suggesting thereby that malaria outbreaks can be tackled by the nets if adequate treated nets are stored in core problem districts. It was also revealed that An. culicifacies is a late night biter and as such treated nets can be used successfully against this species.

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Evaluation of pirimiphos-methyl (50% EC) against the immatures of Anopheles stephensi/An. culicifacies (malaria vectors) and Culex quinquefasciatus (vector of bancroftian filariasis).

BACKGROUND & OBJECTIVES: In India, temephos and fenthion are used as larvicides in fresh and polluted waters. Since use of same insecticide may precipitate resistant, as an alternative bioefficacy of pirimiphos-methyl--an organophosphorus insecticide was evaluated against immatures of Anopheles and Culex species in different breeding habitats in District Ghaziabad (U.P.) and Goa. METHODS: Laboratory bioassays were carried out using standard WHO procedure. LC50 and LC90 were calculated using Probit analysis. Abbott's formula was used to calculate per cent corrected mortality in laboratory exposures while, Mulla's formula was applied for calculating per cent reduction in mosquito immatures under field conditions. RESULTS: Pirimiphos-methyl was found to be most effective against larvae of An. stephensi followed by An. culicifacies and Cx. quinquefasciatus. The LC50 and LC90 values against three species were 0.023, 0.032 and 0.04 ppm; and 0.045, 0.057 and 0.114 ppm respectively. In field, pirimiphos-methyl @ 200 g a.i./ha against Anopheles species and @ 300 g a.i./ha against Culex species can produce > 80% reduction in density of immatures up to one week in different habitats. Pirimiphos-methyl < 0.25 ppm is not toxic to fish. INTERPRETATION & CONCLUSION: Pirimiphos-methyl is more effective against anophelines in clean water than culicines in polluted water. This larvicide should not be used at a concentration above 0.25 ppm in habitats harbouring the larvivorous fish.

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Impact of residual spraying of Reldan against Anopheles culicifacies in selected villages of District Ghaziabad (Uttar pradesh), India.

BACKGROUND & OBJECTIVES: Indoor residual spraying of Reldan 40% EC @ 0.5 and 1 g/m2 was done in Tatarpur and Chauna villages, respectively in Dhaulana PHC, Distt. Ghaziabad (U.P.) to evaluate its impact against Anopheles culicifacies and malaria incidence. Results were compared with that of Piyawali village which was taken as control area. METHODS: Four rounds of spray were done from 1999--2000 in human dwellings and cattlesheds in experimental villages. Entomological parameters--man hour density, parity rate, sporozoite rate, etc. were monitored using standard procedures. Epidemiological indicators such as SPR, SFR, cases/000, Pf/000 were also calculated. Cone bioassays as per WHO method were also carried out to assess the persistence of the insecticide on different surfaces. RESULTS: Entomological results revealed that spraying of reldan @ 0.5 g/m2 resulted in significant reduction in adult densities of An. culicifacies in sprayed villages over the control village. Spraying also resulted in reduction of percent parous females, reduction in malaria incidence (p < 0.05). INTERPRETATION & CONCLUSION: Reldan showed high efficacy @ 0.5 g/m2 in controlling the densities of An. culicifacies and malaria incidence. However, double dosage of reldan @ 1 g/m2 can be used for comprehensive vector control provided > 95% spray coverage is achieved.

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