title: Development of a Simple Dipstick Assay for Operational Monitoring of DDT.
abstract: BACKGROUND
  Indoor residual spraying (IRS) of DDT is used to control visceral leishmaniasis (VL) in India. However, the quality of spraying is severely compromised by a lack of affordable field assays to monitor target doses of insecticide. Our aim was to develop a simple DDT insecticide quantification kit (IQK) for monitoring DDT levels in an operational setting.
  DDT quantification was based on the stoichiometric release of chloride from DDT by alkaline hydrolysis and detection of the released ion using Quantab chloride detection strips. The assay was specific for insecticidal p,p`-DDT (LoQ = 0.082 g/m2). Bostik discs were effective in post spray wall sampling, extracting 25-70% of active ingredient depending on surface. Residual DDT was sampled from walls in Bihar state in India using Bostik adhesive discs and DDT concentrations (g p,p`-DDT/m2) were determined using IQK and HPLC (n = 1964 field samples). Analysis of 161 Bostik samples (pooled sample pairs) by IQK and HPLC produced excellent correlation (R2 = 0.96; Bland-Altman bias = -0.0038). IQK analysis of the remaining field samples matched HPLC data in identifying households that had been under sprayed, in range or over sprayed.
  
  
  CONCLUSIONS
  A simple dipstick assay has been developed for monitoring DDT spraying that gives comparable results to HPLC. By making laboratory-based analysis of DDT dosing accessible to field operatives, routine monitoring of DDT levels can be promoted in low- and middle- income countries to maximise the effectiveness of IRS.
authors.affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, 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), Agamkuan, Patna - 800 007, India.
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna - 800 007, India.
authors.forename: Rudra P
authors.initials: RP
authors.lastname: Singh
authors.affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Williams
authors.affiliation: Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna - 800 007, India.
authors.forename: Pushkar
authors.initials: P
authors.lastname: Shivam
authors.affiliation: Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna - 800 007, India.
authors.forename: Ayan
authors.initials: A
authors.lastname: Ghosh
authors.affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
authors.forename: Rinki
authors.initials: R
authors.lastname: Deb
authors.affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
authors.forename: Geraldine M
authors.initials: GM
authors.lastname: Foster
authors.affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
authors.forename: Janet
authors.initials: J
authors.lastname: Hemingway
authors.affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Coleman
authors.affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
authors.forename: Marlize
authors.initials: M
authors.lastname: Coleman
authors.affiliation: Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna - 800 007, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Das
authors.affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
authors.forename: Mark J I
authors.initials: MJ
authors.lastname: Paine
mesh_terms: D000336:Aerosols / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000191:economics / Q000295:instrumentation* / Q000379:methods*; D003634:DDT / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry*; D015394:Molecular Structure
chemical_list: D000336:Aerosols; D007306:Insecticides; D003634:DDT