Recent semi-field results from Project BITE under IVCC’s Indo-Pacific Initiative (IPI) have shown that forest packs containing bite prevention tools could have an impact on public health beyond just personal protection. The results come from trials that UCSF-Malaria Elimination Initiative, IVCC’s lead partner on BITE, conducted at AFRIMS (Armed Forces Research Institute of Medical Sciences) and Kasetsart University in Thailand.
Project BITE aims to evaluate the effectiveness of forest packs containing a spatial emanator, topical repellent and insecticide-treated clothing when deployed to forest dwellers, goers and rangers in the Greater Mekong Subregion. The project comprises semi-field trials in Thailand and field trials in Cambodia. The trials conducted at the two sites in Thailand measured the protective efficacy of the products using the following endpoints: landing inhibition, knockdown, delayed mortality at 24 hours and blood feeding inhibition.
The semi-field findings demonstrated that these products not only prevent mosquitoes from landing but can also kill or delay them from seeking another host, thus preventing diversion of mosquitoes to nearby non-users of the tools. Delaying host-seeking and feeding inhibition also could have an additional impact on vectorial capacity by reducing human biting rate (HBR) and the vectors’ lifetime reproductive output.
Following the semi-field trials, a formative assessment is now underway in Mondulkiri province in Cambodia, looking at user acceptability of the products. A field entomology trial will take place in Q3-Q4 2021, and a field epidemiological trial will commence in Q1 2022, both at the same sites in Mondulkiri, which will test the hypotheses coming out of the semi-field results.
IVCC and its partners are hopeful that the evidence generated by BITE will help make the case to national programmes and donors on the effectiveness of forest packs in the fight against outdoor malaria transmission amongst at-risk groups – both in Asia-Pacific and beyond.