Indian Journal of Medical Research

ORIGINAL ARTICLE
Year
: 2012  |  Volume : 135  |  Issue : 3  |  Page : 382--388

Impact of changing over of insecticide from synthetic pyrethroids to DDT for indoor residual spray in a malaria endemic area of Orissa, India


Surya K Sharma1, Ashok K Upadhyay1, Mohammed A Haque1, Prajesh K Tyagi1, Bikrant K Kindo2 
1 National Institute of Malaria Research (NIMR), Field Station, Rourkela, India
2 Office of the Chief District Medical Officer, Sundargarh, India

Correspondence Address:
Surya K Sharma
Scientist - E, National Institute of Malaria Research, Field Station, Sector-5, Rourkela 769 002
India

Background & objectives: Development of insecticide resistance in malaria vectors has been a major problem for achieving effective vector control. Due to limited availability of insecticides, the only option is management of resistance by judiciously using the insecticides and rotating them to maintain their effectiveness. This study was carried out in a malaria endemic area of Sundergarh district in Orissa where synthetic pyrethroids (SP) were in use for the last couple of years. The change-over from SP to DDT was done in one arm of study, and the other two arms remained on SP and insecticide-treated nets (ITN). Entomological and parasitological monitoring was done to assess the impact. Methods: The study design comprised of three arms (i) two rounds of indoor residual spraying (IRS) with DDT 1g/m [2] as a change-over insecticide in areas previously under synthetic pyrethroids; (ii) two rounds of IRS with synthetic pyrethroid (alphacypermethrin, ACM) @ 25 mg/m [2] ; and (iii) an unsprayed area under ITN/long lasting insecticide nets (LNs). Indoor residual spraying was undertaken under strict supervision to maintain quality and coverage. Contact bioassays were conducted to know the persistence of insecticide on sprayed surfaces and adult vector density was monitored in fixed and randomly selected houses. Malaria incidence was measured through fortnightly domiciliary surveillance under primary health care system in all the study villages. Results: The insecticide susceptibility tests showed that An.culicifacies was resistant to DDT but susceptible to malathion and ACM. However, An. fluviatilis was susceptible to all the three insecticides. ACM was effective in killing An. culicifacies on mud and wooden sprayed surfaces and maintained effective bioefficacy ranging from 92 to 100 per cent up to five months, whereas DDT failed to achieve effective mortality in An.culicifacies. However, there was significant decline in the density of An.culicifacies in ACM and DDT areas in comparison to ITNs/LNs. There was 61 per cent reduction in the slide positivity rate in ACM area in comparison to 48 and 51 per cent in DDT and ITN/LNs areas, respectively. The adjusted incidence rate of malaria cases per 1000 population in three study areas also showed significant declines within each group. Interpretation & Conclusions: The present findings show that the change-over of insecticide from synthetic pyrethroids to DDT brings about the same epidemiological impact as envisaged from continuing SP spray or distributing insecticide treated nets/long-lasting insecticidal nets provided there is a good quality spray and house coverage.


How to cite this article:
Sharma SK, Upadhyay AK, Haque MA, Tyagi PK, Kindo BK. Impact of changing over of insecticide from synthetic pyrethroids to DDT for indoor residual spray in a malaria endemic area of Orissa, India .Indian J Med Res 2012;135:382-388


How to cite this URL:
Sharma SK, Upadhyay AK, Haque MA, Tyagi PK, Kindo BK. Impact of changing over of insecticide from synthetic pyrethroids to DDT for indoor residual spray in a malaria endemic area of Orissa, India . Indian J Med Res [serial online] 2012 [cited 2019 Oct 23 ];135:382-388
Available from: http://www.ijmr.org.in/article.asp?issn=0971-5916;year=2012;volume=135;issue=3;spage=382;epage=388;aulast=Sharma;type=0