Zanzibar, with a population of about 1.4 million, is a high-transmission area for malaria but has made huge strides in fight against the disease. This makes it a “unique case study” to test prospects for elimination in other parts of Sub-Saharan Africa where malaria is widespread, according to a study published in BMC Medicine recently.
Isles authorities expect to have completely stopped new malaria infections by 2023, on the basis of projections in the Zanzibar Malaria Elimination Programme, but the study is cautious.
Anders Bjorkman, the lead author of the study, says making available tools accessible to all was the key to success. “This study shows greater impact … thanks to better implementation with higher coverage and the fact that all tools for prevention, diagnosis and treatment were free of charge and thus fully accessible,” he explains.
The researchers accessed data from nine cross-sectional household surveys conducted from May to June each year between 2003 and 2015, in two rural districts. They also used vital monthly data from 26 health facilities for the period between 1999 and 2015.
“Human biting rates (by mosquitoes) decreased by 98 per cent,” according to findings reported in the journal. “The total (malaria) parasite load decreased over 1000-fold (99.9 per cent) between 2003 and 2015.”
Björkman, a senior fellow at the Karolinska Institute, Sweden, told SciDev.Net that what made the difference in Zanzibar was higher coverage of community-based interventions such as insecticide-treated bed nets and indoor residual spray.
He attributes the recent success to commitment of the Zanzibar government, the National Malaria Elimination Programme and participation by community residents.
But Björkman cautions that mosquitoes have resisted control measures in previous years, so new strategies need to be developed in order to win the fight against malaria and see its complete eradication in Zanzibar.
Anders says his team is embarking on a pilot programme to test new strategies — such as outdoor traps that attract and kill mosquitoes outdoors, and mass use of specially targeted drugs.