Table 3. Understand the epidemiology: TDR-supported and/or TDR-authored research for elimination of VL in the Indian subcontinent.
| Early Detection | Complete Treatment | Vector Control |
|---|---|---|
| Phase 1: Understand the epidemiology [14, 78, 79, 83, 85–91, 93–96] | ||
| - What is the VL burden? - How much does a passive reporting underestimate the VL burden? - What are the risk factors? - Are there delays in diagnosis of VL? |
- What is the community’s KAP about VL? - Are there delays in seeking treatment for VL? |
- What vector-control measures are in use? - What is the community awareness on vector control for VL? - How is the quality of IRS in India, Nepal? |
| - Disease burden estimates based on passive surveillance; mortality data sparse based on hospital deaths - VL case fatality rate (6.12%) 17 times higher in tribal population in Bangladesh - Annual incidence up to 22 times higher than elimination target in Indian subcontinent - More than 8-fold underreporting - Poverty impedes early diagnosis and treatment, increases risk to VL; VL in turn reinforces poverty - Low literacy, low caste, large families, poor housing, proximity to water, vegetation, livestock, and sleeping habits increases risk of VL - Delay in seeking care 3.75 times more in Nepal (30 days) than in India - Delay in diagnosis after seeking care 3.6 times more in India (90 days) than in Nepal - Delay in reporting to health system more in Nepal (76 days) than in India (28 days) |
- High awareness of VL except in Bangladesh - Provider choice: formal and informal private medical practitioners (India); chemist shops and health centres (Nepal); health centres (Bangladesh) - Long delays in diagnosis and start of treatment; provider shopping by patient before availing treatment in public sector (India) - No delays from diagnosis to start of treatment in India, Nepal |
- Low community awareness on VL prevention through vector control - Very limited IRS but high community use of bed nets in Bangladesh - IRS spraying substandard, suboptimal insecticide bioavailability on sprayed surfaces, SF resistance to DDT widespread (India), SF susceptible to pyrethroids (Nepal) |
| Phase 2: Validate the elimination strategy [85, 97–105] | ||
| - Does ACD increase yield of new VL cases? - Does ACD reduce delays in diagnosis and treatment of VL? - How much effort and cost to find an undetected case through ACD? - Is it cost effective to combine ACD for VL, PKDL with vector control? - Can community participation strategy enhance detection of PKDL cases? |
- Can improved drug management at health centre improve patient satisfaction, reduce treatment delay, and strengthen compliance? | - What is the efficacy of different vector-control tools? - Is ITN efficacious and acceptable in Bangladesh? - Is DWL vector-control method safe, efficacious in Bangladesh? |
| - Active house-to-house screening identifies 20% to 100% more VL cases depending on the endemicity levels among districts - ACD results in patients spending less for diagnosis and correct treatment - ACD (house screening) is cost effective in districts with poor surveillance systems - Effort and cost to detect new VL case through ACD increases as VL incidence decreases - Combining camp (fever, skin lesions) with ITN strategy is cost effective in detecting new cases of VL, PKDL, tuberculosis, leprosy, and malaria and reducing SF density by 86% (India), 32% (Nepal) at 4 weeks - Focal search around 32 VL patients detected 19 new VL patients - ACD of PKDL by trained community health volunteers trained in screening individuals with skin lesions suspected 52 cases, of which 9 were confirmed as PKDL on PCR |
- Treatment of patients hampered by shortage of first-line drugs in India and Nepal; delay in procurement of miltefosine in Bangladesh - Positive experience with drug management at PHC level and patient satisfaction |
- IRS significantly reduced SF density in research setting, LLIN and EVM less and variably effective - IRS (DDT in India, alpha cypermethrin in Nepal) effectiveness is low when implemented by the national program - ITN is highly efficacious even at 6 months; highly acceptable and feasible, less dependent on skilled staff, strong on community involvement - DWL most effective, durable, acceptable but more costly vector-control method, followed by ITN and EVM |
| Phase 3: Compare approaches [73, 74, 105–112] | ||
| - Which diagnostic strategy is most cost effective for VL treatment? - Which is the most cost-effective ACD approach? |
- What are the constraints and benefits of delivering home-based treatment with oral miltefosine? - Does home-based treatment with oral miltefosine improve patient management, compliance, and satisfaction? - How does the cost effectiveness of combination therapy compare with mono therapy? |
- What is the most effective vector-control strategy? - What is the comparative cost of intervention? - How do LLIN with different insecticides compare for efficacy in Nepal? - Is DWL cost-effective method for vector control? |
| - Clinical criteria combined with serology most cost-effective diagnostic strategy to treat VL - Blanket search: high yield but requires high effort, expensive and difficult to sustain - Camp search: optimal for high endemicity districts - Focal search: optimal for low to moderate endemicity areas - Incentive-based approach: high yield but may not be acceptable to national health system |
- Performance of primary HCP in patient management is still hampered - Patient satisfaction with VL treatment in public sector is reasonable - PM least expensive treatment option, cost per YLL or death averted least for PM (US$2–US$53) and highest for L-AmB (US$22–US$527) |
- IRS most effective strategy, LLIN promising alternative in Nepal, Bangladesh - LLIN significantly efficacious even after 18 months of use - IRS (India), ITN less expensive than EVM, delivery costs low, costs sensitive to cost of material (bed net, insecticide) - DWL (reduced surface area) safe, efficacious, cost-saving option for vector control compared to DWL (full surface area) - IRS combined with ITN more effective than IRS or ITN alone; acceptance higher |
| Phase 4: Translate research to practice and public health [11, 106, 111, 113–115] | ||
| - Is it feasible, acceptable, and cost effective for national VLEP to scale up ACD appropriate to the endemicity level of VL? - What is the additional cost and human resource requirement for ACD to be scaled up by national VLEP? - What aspects of the VLEP need to be strengthened? |
- What are constraints of patient management at PHC and at home for improved health services performance? | - What are the performance indicators to assess IRS? - How can quality of IRS in national programme be improved? - Is community-based intervention with ITN effective in reducing VL in Bangladesh? - Is IRS effective in India and Nepal when delivered by national programmes? |
| - National programme can adapt camp, focal search ACD strategies but require adequate time and resources for planning, training, and strengthening referral - ACD strategies can be scaled up by national programme with current staff with training; scale up easier if all staff positions filled - Need to strengthen disease and vector surveillance, ACD strategies, ITN, IRS, supply of drugs and RDTs, develop innovative BCC activities, resources for vector control (Nepal) |
- Monitoring and evaluation tool kit for IRS developed and validated to detect constraints in IRS operations and trigger timely response - Hand compression pump easier to use, lower weight, lower operation cost, safer, higher spray coverage area, more efficient than stirrup pump - Community intervention with ITN reduced VL incidence by 66.5% |
|
Abbreviations: ACD, active case detection; BCC, behavioral change communication; DDT, dichloro-diphenyl-trichloroethane; DWL, durable wall lining; EVM, environment vector management; HCP, health care provider; IRS, indoor residual spraying; ITN, insecticide treated nets; KAP, knowledge attitude practice; L-AmB, liposomal amphotericin B (AmBisome); LLIN, long lasting insecticide nets; PCR, polymerase chain reaction; PHC, primary health center; PM, Paromomycin; RDT, rapid diagnostic test; SF, sand fly; VLEP, Visceral Leishmaniasis Elimination Programme; YLL, years life lost.