title: DDT-based indoor residual spraying suboptimal for visceral leishmaniasis elimination in India.
abstract: Indoor residual spraying (IRS) is used to control visceral leishmaniasis (VL) in India, but it is poorly quality assured. Quality assurance was performed in eight VL endemic districts in Bihar State, India, in 2014. Residual dichlorodiphenyltrichloroethane (DDT) was sampled from walls using Bostik tape discs, and DDT concentrations [grams of active ingredient per square meter (g ai/m(2))] were determined using HPLC. Pre-IRS surveys were performed in three districts, and post-IRS surveys were performed in eight districts. A 20% threshold above and below the target spray of 1.0 g ai/m(2) was defined as "in range." The entomological assessments were made in four districts in IRS and non-IRS villages. Vector densities were measured: pre-IRS and 1 and 3 mo post-IRS. Insecticide susceptibility to 4% DDT and 0.05% deltamethrin WHO-impregnated papers was determined with wild-caught sand flies. The majority (329 of 360, 91.3%) of pre-IRS samples had residual DDT concentrations of <0.1 g ai/m(2). The mean residual concentration of DDT post-IRS was 0.37 g ai/m(2); 84.9% of walls were undersprayed, 7.4% were sprayed in range, and 7.6% were oversprayed. The abundance of sand flies in IRS and non-IRS villages was significantly different at 1 mo post-IRS only. Sand flies were highly resistant to DDT but susceptible to deltamethrin. The Stockholm Convention, ratified by India in 2006, calls for the complete phasing out of DDT as soon as practical, with limited use in the interim where no viable IRS alternatives exist. Given the poor quality of the DDT-based IRS, ready availability of pyrethroids, and susceptibility profile of Indian sand flies, the continued use of DDT in this IRS program is questionable.
authors.affiliation: Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom;
authors.forename: Michael
authors.initials: M
authors.lastname: Coleman
authors.affiliation: Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom;
authors.forename: Geraldine M
authors.initials: GM
authors.lastname: Foster
authors.affiliation: Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom;
authors.forename: Rinki
authors.initials: R
authors.lastname: Deb
authors.affiliation: Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Sadikpur, Patna, Bihar 800007, India.
authors.forename: Rudra
authors.initials: R
authors.lastname: Pratap Singh
authors.affiliation: Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom;
authors.forename: Hanafy M
authors.initials: HM
authors.lastname: Ismail
authors.affiliation: Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Sadikpur, Patna, Bihar 800007, India.
authors.forename: Pushkar
authors.initials: P
authors.lastname: Shivam
authors.affiliation: Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Sadikpur, Patna, Bihar 800007, India.
authors.forename: Ayan Kumar
authors.initials: AK
authors.lastname: Ghosh
authors.affiliation: Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom;
authors.forename: Sophie
authors.initials: S
authors.lastname: Dunkley
authors.affiliation: Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Sadikpur, Patna, Bihar 800007, India.
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom;
authors.forename: Marlize
authors.initials: M
authors.lastname: Coleman
authors.affiliation: Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom; janet.hemingway@lstmed.ac.uk.
authors.forename: Janet
authors.initials: J
authors.lastname: Hemingway
authors.affiliation: Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom;
authors.forename: Mark J I
authors.initials: MJ
authors.lastname: Paine
authors.affiliation: Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Sadikpur, Patna, Bihar 800007, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Das
mesh_terms: D000818:Animals; D003634:DDT; D006801:Humans; D007194:India / Q000453:epidemiology; D007303:Insect Vectors; D007305:Insecticide Resistance; D007306:Insecticides; D007898:Leishmaniasis, Visceral / Q000453:epidemiology / Q000517:prevention & control*; D011576:Psychodidae
chemical_list: D007306:Insecticides; D003634:DDT
keywords: DDT; IRS; India; elimination; leishmaniasis