Dr. Silas Majambere is a medical entomologist who took up the position od senior scientist with the Innovative Vector Control Consortium recently. MalariaWorld asked Silas about his past work and future ambitions in the field of malaria elimination.
You have been working directly in the field of operational malaria control in The Gambia using larval control. What is your current opinion on the role of larval control? Is it indeed a matter of ‘few, fixed, and findable’ sites or is there a wider role for larval control?
I have spent four years in The Gambia investigating the role of larviciding for malaria control. The program covered 400 km2 of floodplains with ground teams of spraymen applying Bacillus thuringiensis Israelensis (Bti) weekly to all water bodies we had previously mapped. This was indeed hard work at +40 degrees Celsius, and I commend the team that took the task. Unfortunately we only had a small impact on adult mosquito density and were not able to show a reduction in malaria prevalence following the larviciding program.
There were two main reasons we were not able to show impact: (1) the extent of the floodplains is simply too large to spray by ground teams, unless bigger teams are deployed; (2) Gambia river is highly tidal and Bti is likely to have been washed away after application.
Larval source management (LSM) has a role in malaria control, and it is not just my opinion, but it is historically proven (Brazil, Israel, USA, etc.). Although I understand the caution around “few, fixed and findable”, those terms are very relative and should not distract us.
Many African countries have adopted LSM for malaria control, and it is one of the tools in their Strategic Plans. While the scientific community is debating, the train has moved, and we’d better catch up and support the countries adopt best practices for LSM, including robust monitoring and evaluation, and use of WHOPES recommended products. With the technology we have today, I believe we can design better LSM programs than 80 years ago in Brazil.