Toolkit for Monitoring and Evaluation of Indoor Residual Spraying for Visceral Leishmaniasis Control in the Indian Subcontinent: Application and Results

Abstract

Background. We field tested and validated a newly developed monitoring and evaluation (M&E) toolkit for indoor residual spraying to be used by the supervisors at different levels of the national kala-azar elimination programs in Bangladesh, India and Nepal. Methods. Methods included document analysis, in-depth interviews, direct observation of spraying squads, and entomological-chemical assessments (bioassay, susceptibility test, chemical analysis of insecticide residues on sprayed surfaces, vector density measurements at baseline, and three follow-up surveys). Results. We found that the documentation at district offices was fairly complete; important shortcomings included insufficient training of spraying squads and supervisors, deficient spray equipment, poor spraying performance, lack of protective clothing, limited coverage of houses resulting in low bioavailability of the insecticide on sprayed surfaces, and reduced vector susceptibility to DDT in India, which limited the impact on vector densities. Conclusion. The M&E toolkit is a useful instrument for detecting constraints in IRS operations and to trigger timely response.

DDT-based indoor residual spraying suboptimal for visceral leishmaniasis elimination in India

“…Given that effective prevention through vector control and rapid diagnosis and treatment methodologies exist (7,16), elimination of VL in this region should therefore be technically feasible. However, in order for the predicted outcomes of IRS to become a reality, the IRS itself must be of sufficient quality to achieve an impact (17,18).…”

Towards elimination of visceral leishmaniasis in the Indian subcontinent—Translating research to practice to public health

“…The tool kit was useful for detecting operational constraints in IRS, such as inadequate training of spraying squads, supervisors, deficient equipment, poor spray performance, limited surface coverage in households, etc., and triggering a timely response [106]. The Regional Technical Advisory Group recommended the adoption of the TDR monitoring and evaluation tool kit for IRS by the national VL elimination programmes in 2013 [119].…”

Optimizing Insecticide Allocation Strategies Based on Houses and Livestock Shelters for Visceral Leishmaniasis Control in Bihar, India

“…In particular, only 30% of the total number of houses in Bihar can be sprayed, annually, under the present DDT allocation policy (0.037 kg/person). However, studies 12 have shown that when only houses are sprayed, there is no change in the density of the sandflies found in the non-sprayed region, suggesting that other regions should be considered. Hence, incorporating cattle sheds in the insecticide-spraying program (in addition to houses) may be a more effective strategy in interrupting VL transmission.…”

“…20 Moreover, the appropriate empirical studies were used to estimate P. argentipes' insecticide-induced mortality, 24 hours after spraying with DDT 12 and deltamethrin. 16 An insecticide's lethal effect is assumed to decay exponentially over time 21 as suggested in the literature.…”

“…A study 12 on IRS identified two main issues adversely affecting IRS effectiveness in India: 1) a lack of mass community effect 13 (reduction in overall sandfly population including in unsprayed houses) because of insecticide sprayed at a few dispersed (targeted) houses and 2) reduced susceptibility (increased resistance) of sandflies to dichlorodiphenyltrichloroethane (DDT). Recently, these two issues (addressed by this model) have been causing lower reduction levels of sandfly densities after the implementation of an IRS campaign.…”