Visceral leishmaniasis (VL)/kala-azar (KA) is a public health problem in the Indian subcontinent, particularly in Bangladesh, India and Nepal [
The main purpose of the M&E toolkit is to support IRS programmes through systematic monitoring and evaluation of processes and outcomes, allowing timely detection of gaps and constraints and ensuring that adequate responses are taken. Details about the toolkit can be found in the WHO website (
M&E toolkit for IRS.
The study has been carried out from April 2009 to June 2010 in 9 districts in India and Nepal and in two Upazilas (subdistricts) in Bangladesh by 5 research teams: Institute of Medicine (IOM) at the Tribhuvan University in Kathmanadi/Nepal (Sarlahi, Dhanusha and Mahottari districts); BP Koirala Institute of Health Sciences (BPKIHS) in Dharan, Nepal (Morang, Sunsari, and Saptari); Rajendra Memorial Research Institute of Medical Sciences (RMRIMS) in Patna, Bihar, India (Muzaffarpur, Vaishali, and Samastipur) and International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), and the National Institute of Preventive and Social Medicine (NIPSOM), Dhaka, Bangladesh (Trishal Upazilla and Fulbaria Upazila in Mymensingh District) (Figure
Study area map.
In India, two primary health care centres (PHCs) were selected from each of the above-mentioned districts, in total six PHCs, chosen on the basis of previous VL case load. Twelve villages (two from each PHC, one close and one far away from the PHC) were selected randomly for assessing the IRS operations. Additionally, four villages were randomly selected as control area for the assessment of vector densities. In Nepal, in the six study districts, 24 village development committees (VDCs) were selected based on high VL case load according to passive surveillance data. In each district, two VDCs were near and two were distant from the district headquarter from where the IRS program was operated. The 24 VDCs were then divided in those where IRS was programmed and those where it was not. From each VDC one study village was selected randomly so that in the end 12 IRS intervention villages and 12 control villages were assessed. In Bangladesh, 3 and 4 villages were selected from Fulbaria and Trishal Upazila, respectively, according to the VL endemicity, and IRS has been carried out by the programme. Additionally, in each Upazila one village far away from the IRS village was selected randomly as a control (Figure
Study design.
All vector control staff involved in IRS operations from central to field level including spray men were assessed in the study and a random selection of households in IRS areas were interviewed.
The main outcome variable of IRS is the reduction of vector density. Hence the assumptions for the sample size calculations for vector density measurement were as follows. An 80% reduction of vector density would be achieved at 4 weeks after IRS; the sandfly counts were expected to follow a negative binomial distribution with a dispersion parameter of
The sample-size calculation for analysing spraying activities was based on the assumption that 70% of the observed spraying activities would be of an acceptable standard (with 15% precision and 95% confidence level). This resulted in a target of at least 36 different spray teams to be observed in each study area. All sites (except one) exceeded the minimum number ensuring a higher power of the study.
Anticipating a coverage and acceptance of 80% and requiring a 95% confidence interval of the length +/−5 units, the sample size of households to be interviewed is 246. Given the inclusion of 12 villages, a sample size of 30 houses per village was found to be feasible resulting in 360 households per study site.
Information regarding input indicators, that is, existence of guideline and national action plan, certification of chemical in use, training of spray teams, and availability of insecticide was collected before IRS using a structured questionnaire and interviewed by the investigators from Director, National Vector Borne Disease Control Programme (NVBDCP) and Senior Programme Officer, State Health Society, Bihar, and District Malaria Officer (DMO) in India; Director, Epidemiology and Disease Control Division (EDCD) in Nepal and director, Disease control; Deputy Programme Manager (DPM), Kala-azar Control Programme and Chief Health Superintendent (CHS) of Directorate General of Health Services (DGHS) in Bangladesh.
The detailed information regarding spraying activities (operational plan) was collected through an interview with a structured questionnaire by the investigators from Medical Officer In-Charge (MOIC), Primary Health Centre (PHC) in India and Vector Control Manager in Nepal and Upazila Health and Family Planning Officer (UH&FPO) and Health Inspector (HI) in Bangladesh.
Standardized observations were made with a checklist used by trained field research assistants; the observation checklist included information about (A) mixing of insecticide, spraying techniques (width of swath, distance of nozzle from wall); management of leftover insecticide, presence of supervisor, (B) the number of houses sprayed par spray man per day and the amount of insecticide used per house were calculated in randomly selected houses.
We calculated the coverage of IRS and peoples’ satisfaction through formal household interviews applied by trained field research assistants.
Ten sandflies were exposed on each of 4 walls using WHO plastic cones [
Bioassays were done at 2 weeks, 4 weeks, and 5 months after IRS.
Before spraying and without knowledge of the spray men, four filter papers (Whatman no. 1,
Five DDT-WP filter papers from India and 6 lambda-cyhalothrin-WP filter papers from Nepal along with standard DDT and cyhalothrin WP formulations were retested by the WHOPES (World Health Organization Pesticide Evaluation Scheme) collaborating Centre in Belgium (Centre Wallon de Recherches Agronomiques, CRA-W, Gembloux, Belgium) and by the Liverpool School of Tropical Medicine.
Insecticide susceptibility was tested in one site (India) in tube bioassays, using the WHO’s standard chamber method [
Sandfly densities were measured in IRS intervention villages and in control villages at 2-weeks before spraying and at 2, 4, and 20 weeks after spraying through the collection of sandflies with CDC light traps which is preferred to the aspirator method [
The monitoring of VL cases over time through routine surveillance and active case detection [
A database was developed by the data management centre at ICDDR,B in Bangladesh, using EPI Info software version 3.5.1 to enter field as well as laboratory data. Data were cleaned and checked in duplicate. Descriptive analysis was performed and 95% Confidence Interval (CI) was calculated using Normal as well as a Binomial distributional approach where applicable. The percent reduction (
The effect is negative/positive if sandfly density is decreased/increased after intervention and the effect should be zero if the sandfly density is same as baseline. All calculations were performed by STATA 10.
The study protocol was approved by the ethical review committee (ERC) at WHO Geneva and in each research institution by their respective ethical boards. Informed written consent was obtained from vector control staff involved with IRS operations from central to field level operation and from households which have been interviewed.
Input indicators of the M&E toolkit revealed that district action plans and guidelines for IRS were in place across the all study sites. Except for the subdistricts in Bangladesh, all other study districts in India and Nepal had proper storage facilities for insecticides. However, the proportion of functional pumps was low and the availability of spare parts was inadequate in India and in half of the study districts in Nepal (Table
Input indicators for IRS: availability of different resources for conducting IRS.
Samastipur, Muzaffarpur, and Vaishali | Sunsari, Morang, and Saptari (Nepal) | Sarlahi, Dhanusa, and Mahottari | Fulbaria | Trishal | |
---|---|---|---|---|---|
Existence of guideline and action plan | Yes | Yes | Yes | Yes | Yes |
Type of insecticide to be used | DDT | Lambdacyhalothrin | Lambdacyhalothrin | Deltamethrin | Deltamethrin |
Adequate storage facility | Yes | Yes | Yes | No | No |
Average % of functional pumps | 79.6% | 94.4% | 78.3% | 100% | 100% |
Have enough spare parts | No | No | Yes | Yes | Yes |
Training (days) for spray man before going to IRS | No | Yes | Yes | Yes | Yes |
Protective clothing available | Not provided | Partially provided | Partially provided | Partially provided | Partially provided |
*Pilot areas for new national programme. Pumps were either hired from neighbouring sub-districts or provided by research team.
In general process indicators of the M&E toolkit reflected nonhomogeneous spraying performance within and between countries (Table
Findings of process indicators: observation of spraying squad at community level.
Statements | Samastipur, Muzaffarpur, Vaishali | Sunsari, Morang, Saptari | Sarlahi, Dhanusa, Mahottari | Fulbaria | Trishal |
Number of spraying squads observed | 51 | 31 | 112 | 120 | 120 |
General condition of the pump | |||||
(i) no leakage present | 39 (76.5%) | 31 (100%) | 112 (100%) | 120 (100%) | 120 (100%) |
(ii) pressure gauze present | Not applicable | 0 (0.00%) | 50 (44.6%) | 120 (100%) | 0 (0.00%) |
Adequate filling of the pump | 0 (0.00%) | 31 (100%) | 112 (100%) | 120 (100%) | 120 (100%) |
Proper mixing insecticide was done | 15 (29.4%) | 31 (100%) | 111 (99.1%) | 120 (100%) | 120 (100%) |
Proper distance of nozzle from surface maintained (ideally 45 cm from the surface) | 25 (49.0%) | 0 (0.00%) | 112 (100%) | 97 (80.8%) | 77 (64.2%) |
Proper spray swath (ideal width 65–70 cm) | 30 (58.8%) | 0 (0.00%) | 112 (100%) | 120 (100%) | 78 (31.7%) |
Marking of sprayed houses (stencils) | |||||
(i) spray cycle (mentioned) | 51 (100%) | 0 (0.00%) | 112 (100%) | 0 (0.00%) | 0 (0.00%) |
(ii) group number (mentioned) | 0 (0.00%) | 0 (0.00%) | 94 (83.9%) | 0 (0.00%) | 0 (0.00%) |
(iii) team number (mentioned) | 51 (100%) | 0 (0.00%) | 94 (83.9%) | 120 (100%) | 120 (100%) |
(iv) spray man number (mentioned) | 0 (0.00%) | 0 (0.00%) | 94 (83.9%) | 120 (100%) | 120 (100%) |
(v) number or rooms sprayed | 0 (0.00%) | 0 (0.00%) | 94 (83.9%) | 0 (0.00%) | 0 (0.00%) |
(vi) name of the insecticide sprayed | 51 (100%) | 0 (0.00%) | 94 (83.9%) | 0 (0.00%) | 0 (0.00%) |
(vii) number of charges applied | 0 (0.00%) | 0 (0.00%) | 94 (83.9%) | 0 (0.00%) | 0 (0.00%) |
(viii) date of spray (dd/mm/yy-mentioned) | 51 (100%) | 0 (0.00%) | 112 (100%) | 120 (100%) | 120 (100%) |
Use of safety measures: | |||||
(i) masks | 0 (0.00%) | 1 (33.3%) | 112 (100%) | 105 (87.5%) | 111 (92.5%) |
(ii) gloves | 0 (0.00%) | 0 (0.00%) | 58 (51.8%) | 0 (0.00%) | 0 (0.00%) |
(iii) coat/apron | 0 (0.00%) | 0 (0.00%) | 37 (33%) | 0 (0.00%) | 0 (0.00%) |
(iv) caps | 0 (0.00%) | 0 (0.00%) | 51 (45.9%) | 0 (0.00%) | 0 (0.00%) |
(v) boots | 0 (0.00%) | 0 (0.00%) | 49 (44.1%) | 0 (0.00%) | 0 (0.00%) |
(vi) goggles | 0 (0.00%) | 0 (0.00%) | 10 (9%) | 56 (46.7%) | 111 (92.5%) |
Supervisor was present during spraying | 51 (100%) | 0 (0.00%) | 0 (0.00%) | 53 (44.2%) | 120 (100%) |
Instruction given to the households | |||||
(i) to stay outside during spraying | 100 (100%) | 31 (100%) | 112 (100%) | 120 (100%) | 120 (100%) |
(ii) to prepare the room before spraying | 100 (100%) | 31 (100%) | 112 (100.0) | 120 (100%) | 120 (100%) |
How were the leftover insecticide handled | |||||
(i) buried | 0 (0.00%) | 0 (0.00%) | 112 (100%) | 43 (35.8%) | 9 (7.5%) |
(ii) poured into nearby water | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) | 108 (90%) |
(iii) keep it for future use | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) |
(iv) no left over | 51 (100%) | 31 (100%)* | 0 (0.00%) | 77 (64.2%) | 3 (2.5%) |
How insecticide pouch and sacks disposed | |||||
(i) buried | 0 (0.00%) | 0 (0.00%) | 112 (100%) | 0 (0.00%) | 0 (0.00%) |
(ii) thrown nearby water | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) |
(iii) kept for future use | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) |
(iv) no left over | 6 (1.4%) | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) | 0 (0.00%) |
(v) squad leader took to UHC/PHC/supervisor | 45 (88.2%) | 31 (100%) | 0 (0.00%) | 120 (100%) | 120 (100%) |
*Used for partial spray of unsprayed house.
When analyzing the records of spraying squads it was recorded that the reporting of spray activities at the operation level was very good in all study areas: 95% to 100% of target houses and target populations had been covered. Only the Indian records showed a more realistic picture: the coverage of houses and target populations was only 63.9% (95% CI, 63.6–64.2) and 64.9% (95% CI, 64.8–65.1), respectively (Table
Findings of output indicators: review of documents of spraying programme at district/subdistrict after IRS.
Statements | Samastipur, Muzaffarpur, Vaishali | Sunsari, Morang, Saptari | Sarlahi, Dhanusa, Mahottari | Fulbaria | Trishal |
---|---|---|---|---|---|
Record forms available (seen by observer) | Yes | Yes | Yes | Yes | Yes |
Timely reporting (within 1 week of spraying) | Yes | Yes | Yes | Yes | Yes |
Completeness of record (record from all the sprayed areas) | Yes | Yes | Yes | Yes | Yes |
Number of targeted houses for spraying (calculate structures into houses) | 1,120,946 | 65,30 | 8,289 | 3,032 | 2,833 |
Targeted population (the population targeted for spraying in the action plan) | 5,759,799 | 129,550 | 87,570 | 13,611 | 12,822 |
How many squad/team you need for targeted population? | 734 | 31 | 55 | 2 | 3 |
Spray pumps: | |||||
(i) total pumps (district/subdistrict level) | 1144 | 242 | 226 | 10 | 10 |
(ii) functioning | 849 | 124 | 147 | 10 | 10 |
(iii) repairable | 289 | 80 | 70 | 0 | 0 |
(iv) unrepairable | 6 | 38 | 9 | 0 | 0 |
Sprayed households (% of target achieved according to spraying squads) | 716,498 (63.9%) | 6,290 (96.3%) | 7611 (97.0% ) | 3,032 (100%) | 2,833 (100%) |
Covered population (% of population protected according to spraying squads) | 3,740,157 (64.9%) | 124,745 (96.3%) | 74300 (95%) | 13,611 (100%) | 12822 |
IRS was highly accepted by the community people in all sites and negligible side effects were reported after IRS. However, in all study sites (except one site in Nepal) instructions from spray men were rarely received about how to prepare their houses for the spraying or to leave the house while the spraying was done or not to mud plaster or paint the wall after spraying (Table
Findings of output indicators: IRS acceptability at community level.
Samastipur, Muzaffarpur, Vaishali | Sunsari, Morang, | Sarlahi, Dhanusa, Mahottari | Fulbaria | Trishal | |
Do you like your house to be sprayed? | 419 (100%) | 363 (91.9%) | 233 (95.1%) | 357 (85%) | 419 (100%) |
After spraying do you have any side effect (multiple answer allowed)? | |||||
(i) vomiting | 0 (0.0%) | 3 (0.76%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) |
(ii) sneezing | 10 (2.3%) | 1 (0.25%) | 0 (0.0%) | 7 (1.6%) | 3 (0.7%) |
(iii) itching | 3 (0.7%) | 6 (1.52%) | 0 (0.0%) | 5 (1.1%) | 4 (1.0%) |
(iv) dizziness | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 3 (0.7%) | 0 (0.0) |
(v) headache | 0 (0.0%) | 1 (0.25%) | 0 (0.0%) | 7 (1.6%) | 5 (1.2%) |
(vi) nausea | 0 (0.0%) | 1 (0.25%) | 0 (0.0%) | 8 (1.9%) | 5 (1.2%) |
(vii) others | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) |
Before spraying did you get any advice like removing or covering (number and % of responses)? | |||||
(i) cloths | 329 (78.5%) | 385 (97.5) | 245 (100) | 420 (100) | 418 (99.5) |
(ii) food/utensils | 395 (94.2%) | 385 (97.5) | 245 (100) | 420 (100) | 418 (99.5) |
(iii) children | 419 (100%) | 384 (97.2) | 245 (100) | 420 (100) | 417 (99.3) |
(iv) animals take out from cattle shed | 336 (80.1%) | 352 (89.11) | 245 (100) | 420 (100) | 410 (97.6) |
Have you been advised about the time you should wait to enter the house after spraying is completed? | 138 (32.9%) | 140 (35.4) | 245 (100.0) | 142 (33.8) | 102 (24.3) |
Have you been advised about the time you should not mud plaster or paint the wall after spraying | 87 (20.7) | 113 (28.6) | Not done | 420 (100) | 187 (44.6) |
The bioviability of insecticides on sprayed surfaces was in all sites below the accepted standard at almost all the follow-up timepoints (Figure
Findings of output indicator: bioassay test on IRS surfaces and bioassay results from Baijanathpur-8 and Sundarpur-3 after two weeks of spraying and from Baijanathpur-8 after four weeks of spraying were not included due to high mortality in control tests.
The test results of 311 filter papers showed that average chemical concentrations on sprayed surfaces were adequate to low in three sites (Fulbaria/Bangladesh with 15.1 mg/m2 (+/−14.1 SD) deltamethrin and 15.6 mg/m2 (+/−20.4 SD) lambdacyhalotrin in the two Nepali sites. In the “experimental area” of Trishal (pilot spraying for the national programme) there was a tendency for “overspraying” with 155.7 mg/m2 (+/−270.2 SD) deltamethrin. The proportion of clearly undersprayed walls (i.e., below 7 mg/m2) was 41.7% (90/216). Unfortunately, the results of DDT testing in filter papers by the national laboratory in India could not be reconfirmed by the laboratories in the UK and Belgium and had to be discarded.
Forty-four sets susceptibility test for DDT (4%) against
Susceptibility test for DDT in India.
The main outcome indicator in the M&E toolkit explored whether the current national IRS programmes did achieve a high reduction rate of sandfly densities (Table
Findings of outcome indicator: Sandfly density.
Mean number | % reduction attributed* | ||||
Intervention | Sentinel | Control | Intervention | Sentinel | |
(i) Baseline | 2.81 | 2.26 | 2.19 | — | — |
(ii) 2 weeks followup | 0.24 | 2.43 | 2.54 | −103.91 | −7.96 |
(iii) 4 weeks followup | 0.5 | 2.49 | 2.53 | −94.31 | −4.87 |
(iv) 5 months followup | 1.15 | 1.83 | 2.06 | −54.45 | −13.27 |
(i) Baseline | 5.08 | 4.71 | 16.92 | — | — |
(ii) 2 weeks followup | 0.27 | 0.19 | 15.92 | −75.00 | −74.73 |
(iii) 4 weeks followup | 1.45 | 3.79 | 8.38 | 96.65 | 161.78 |
(iv) 5 months followup | 2.21 | 1.56 | 7.67 | 125.59 | 129.51 |
(i) Baseline | 13.94 | — | 27.49 | — | — |
(ii) 2 weeks followup | — | — | — | — | — |
(iii) 4 weeks followup | 3.53 | — | 11.19 | 42.25 | — |
(iv) 5 months followup | 2.64 | — | 15.99 | 1.43 | — |
(i) Baseline | 5.4 | — | 4.5 | — | — |
(ii) 2 weeks followup | — | — | — | — | — |
(iii) 4 weeks followup | 1.22 | — | 1.22 | −16.67 | — |
(iv) 5 months followup | 0.06 | — | 0.32 | −21.48 | — |
*Note: negative and positive signs represent reduction and increment of
The study showed that the newly developed M&E toolkit successfully identified the shortfalls of IRS in the Indian subcontinent. IRS is an operationally challenging programme which includes a set of activities requiring (a) close coordination among national, state (India), district, and subdistrict authorities, (b) a number of technical ingredients such as insecticides, storage facilities, spraying pumps, spare parts, and protective clothing, and (c) training and supervision in order to achieve the necessary level of reduction of vector densities to interrupt disease transmission. Our study reconfirmed the original hypothesis that through systematic monitoring, the weak parts in the chain from the procurement of materials to the final endpoint reduction of sandfly vectors can be identified and solutions can be sought. The newly developed M&E toolkit was applied by spray supervisors, DMOs/DPHOs/UH&FPOs, and some elements by external reviewers from the research institutions (mainly observation of spraying performance, satisfaction survey and entomological tests). The toolkit was able to identify: cross-cutting issues in all or most sites: poor spraying techniques, lack of protective clothing, poor marking of houses, deficient advice to household members regarding the spraying, and limited effect on the vector population. site-specific problems: lack of training (Bangladesh, India), many deficient spraying pumps (India), poor filling of pumps (India), poor disposal of left-over insecticides (Bangladesh), poor marking of sprayed houses (Nepal), low coverage of targeted houses (India), high level of insecticide resistance (India).
As a result there were serious IRS effectiveness issues: bioassays indicated low standard of spraying and/or elevated insecticide resistance (as wild caught sandflies were used for the tests) or poor insecticide quality; the reduced insecticide susceptibility of sandflies for DDT in India (in contrast, in Nepal the susceptibility of sandfly vectors is still high for deltamethrin [ the reduction of vector densities was low, even in India where sprayed house showed a high vector reduction but unsprayed sentinel houses showed no reduction at all pointing to a lack of mass effect on the vector population by IRS.
The chemical concentration of insecticides on sprayed surfaces as determined by a national laboratory was unexpectedly low compared to two European laboratories used for validation and quality control. These tests in the laboratory are time consuming, expensive, and susceptible to errors. Thus RDTs (rapid diagnostic test) for chemical residuals on sprayed walls are very important in this situation, and it is hoped that an RDT for chemical residuals on sprayed walls will soon be available [
Monitoring and evaluation activities only make sense if the findings are certified by the relevant authority and followed by adequate response mechanisms. However, this was beyond the scope of this particular study which assessed the performance of the M&E toolkit. The recommendations coming out of the analysis were summarized after completing the spraying cycle and were then discussed in training workshops with UH&FPOs in Bangladesh (2 UH&FPOs), DMOs in India (31 DMOs), and DPHOs in Nepal (16 DPHOs). These workshops were used for analyzing the acceptance of the toolkit and provided opportunities for the “triangulation” of the study results. It was found that DMOs/DPHOs/UH&FPOs were almost unanimously satisfied with the toolkit; they were aware of several issues detected in this study (e.g., inadequate training for spray men and supervisors, shortage of good quality pumps and spare parts, lack of proper supervision during spraying, etc.) but not of others (e.g., limited impact on the vector population; resistance issues) and, more importantly, further issues were raised such as the slow cash flow within districts to spraying squads resulting in delays of payment or the lack of travel funds for supervisors and sometimes even for the spray men. Meetings with the relevant district authorities were arranged in order to address these problems. It can be expected, however, that it will take some time until improved training and supervision together with the systematic application of the M&E toolkit by programme managers will be in place leading to improved IRS operations in our study districts and beyond. Of special concern is the stirrup pump used traditionally in India for DDT spraying as it is difficult to manage, less efficient than the compressor pumps used in Nepal and Bangladesh, and has higher health hazards [
The M&E toolkit was useful for identifying major shortcomings in IRS operations. Therefore the M&E toolkit developed with the help of WHO-TDR should be adopted and systematically applied by the programme of the three countries to achieve the expected outcome of IRS.
The paper was funded by the Special Programme for Research and Training in Tropical Diseases (WHO/TDR) in Geneva, Switzerland. The authors thank Drs. A.C. Dhariwal (National Vector Borne Disease Control Programme, New Delhi), R. N. Pandey (Bihar State Health Society, India), F. H. M. Nurunnabi Chowdhury (Directorate General of Health Services, Dhaka, Bangladesh), G. D. Thakur (Epidemiology and Disease Control Division, Kathmandu, Nepal), and the German cooperation BMZ-GIZ for their continuous support and advice. The authors are grateful to the staff of the Centre Wallon de Recherches Agronomiques (Gembloux, Belgium) for the validation of chemical tests. The authors are also thankful to coworkers in the study teams at the Rajendra Memorial Research Institute of Medical Sciences (Dr. S. K. Kesheri, N. Kumar Sinha, M. Prasad, S. A. Khan, and S. Kumar), Tribhuvan University’s Institute of Medicine (Mr. Krishna Raj Pant, Mr. Nav Raj Bist), B. P. Koirala Institute of Health Sciences (Professor S. Rijal), the Bangladesh National Institute of Preventive and Social Medicine (S. Faria), and the International Centre for Diarrhoeal Disease Research, Bangladesh (D. Ghosh, M. Karmaker). Finally, the authors highly acknowledge the populations in the study villages and are thankful for their active participation and support in many research activities.