V. Evaluation of Cross-Immunity against Type 1 Dengue Fever in Human Subjects Convalescent from Subclinical Natural Japanese Encephalitis Virus Infection and Vaccinated with 17D Strain Yellow Fever Vaccine
In this pilot comparative study, we investigated and compared the effects of existing vector control tools on sandfly densities and mortality to inform and support the National Kala-azar Elimination Program (NKEP). The interventions included insecticidal wall painting (IWP), reduced-coverage insecticidal durable wall lining (DWL), insecticide-impregnated bednets (ITN), and indoor residual spraying with deltamethrin (IRS). Sakhua union with seven villages was the study area, which was the most highly endemic visceral leishmaniasis union in Trishal upazila, Bangladesh. Each cluster containing the different interventions included approximately 50 households. Study methods included random selection of clusters, collection of sandfly by CDC light trap and manual aspirator to determine sandfly density, and sandfly mortality determined by WHO cone bioassay test. Trained field research assistants interviewed household heads using structured questionnaires for sociodemographic information, as well as safety and acceptability of the interventions. Descriptive and analytical statistical methods measured interventions’ effect and its duration on sandfly density reduction and mortality. We measured the relative efficacy of IWP on sandfly control against DWL, ITN, and IRS by the difference-in-difference regression model. We found that existing interventions were effective and safe for sandfly control with different duration of effect and acceptability. The relative efficacy of IWP for sandfly reduction varied by –59% to –91%, –75% to –81%, and –30% to –104% compared with DWL, ITN, and IRS, respectively, at different time points during the 12-month follow-up. These study results will guide the NKEP for selection of sandfly control tool(s) in its subsequent consolidation and maintenance phases.
Address correspondence to Dinesh Mondal, NCSD & Emerging Infections and Parasitology Lab, icddr,b, 68, Shaheed Taj Uddin Ahmed Sarani, Mohakhali, Dhaka-1212, Bangladesh. E-mail: firstname.lastname@example.org
Disclaimer: C. H. is a staff member of the WHO and P. O. was a staff member of the WHO at the time of the study. The opinions expressed in this paper are those of the authors and may not represent the views of the WHO.
Authors’ addresses: Debashis Ghosh, Abdul Alim, and Md. Almahmud, International Centre for Diarrhoeal Disease Research Bangladesh, NII, NCSD, Dhaka, Dhaka District, Bangladesh, E-mails: email@example.com, firstname.lastname@example.org, and email@example.com. M. Mamun Huda, International Center for Diarrheal Disease Research, Bangladesh, and Laboratory Sciences Division, Dhaka, Bangladesh, E-mails: firstname.lastname@example.org. Christine M. Halleux, UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland, and Visceral Leishmaniasis Elimination, Geneva, Switzerland, E-mail: email@example.com. Piero L. Olliaro, Oxford University, Tropical Medicine, Oxford, Oxfordshire, United Kindom, E-mail: firstname.lastname@example.org. Greg Matlashewski, McGill University, Microbiology and Immunology, 3775 University, Montreal, Canada, E-mail: email@example.com. Axel Kroeger, University Medical Centre Freiburg, Centre for Medicine and Society, Freiburg, Germany, and Social Sciences, Freiburg, Germany, E-mail: firstname.lastname@example.org. Dinesh Mondal, International Centre for Diarrhoeal Disease Research Bangladesh, Laboratory Sciences Division, Parasitology Laboratory, Mohakhali, Dhaka, Bangladesh, and International Centre for Diarrhoeal Disease Research Bangladesh, Laboratory Sciences Division, Parasitology Laboratory, icddr,b, Mohakhali, Dhaka, Bangladesh, E-mail: email@example.com.