Recent entomological field results from Project BITE under IVCC’s Indo-Pacific Initiative (IPI) have shown that forest packs containing bite prevention tools offer significant protection from landing mosquitoes. The results come from trials that UCSF-MEI, IVCC’s lead partner on BITE, conducted in Mondulkiri province, Cambodia, with the local non-profit Health Forefront Organization.

The entomological trials were conducted in an area directly adjacent to forest and was comprised of 7 temporary shelters designed to mimic short-term dwellings used by people when working or travelling in the forest. Inside each shelter, one of the bite prevention tools, or a combination of all tools, or a control, were used while volunteers collected mosquitoes via Human Landing Catches (HLC) over a 12-hour period.

Over 49 nights of collections, the entomological field study demonstrated that all products – both on their own and in combination – are highly efficacious at preventing mosquitoes from landing. In fact, all products and combinations reduced mosquito landings by at least 60% compared to the control, while the spatial repellent alone and the combination of all products reduced landings by approximately 95%.

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 (GMS). Semi-field trials completed in Thailand in 2021 demonstrated that bite prevention tools not only prevent mosquitoes from landing but can also kill and delay host-seeking.

Following the entomological field studies, Project BITE is currently planning on how best to scale-up use of these tools and further evaluate their epidemiological impact, acceptability, use and cost-effectiveness among high-risk forest-exposed populations.

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 bite prevention tools delivered in forest packs in the fight against outdoor malaria transmission.

Last week, indoor residual spraying began in Papua New Guinea (PNG) as part of a 12-month epidemiological field trial under the NATNAT project led by PNG Institute of Medical Research, PNG National Malaria Control Programme, Burnet Institute, James Cook University and Rotarians Against Malaria (RAM).

The trial is running in 4 villages- Wasab, Bulal, Megiar and Mirap- in the north coast province of Madang, and will assess the effectiveness, feasibility, community acceptability and cost-effectiveness of residual spraying of household structures. The study is designed as an interrupted time series with two interventions over the time period and two control villages.

The trial is part of NATNAT’s wider programme of activity in PNG which aims to develop an evidence-based framework for the rapid assessment and adoption of novel vector control tools (VCTs) and has 4 main objectives:

• Strengthen laboratory, semi-field and field capacity to test new VCTs
• Conduct rigorous field evaluations of new VCTs and implementation (IRS, larval source management and spatial emanators)
• Investigate the community and health system acceptability and cost-effectiveness of new VCTs
• Support a national malaria control programme (NMCP)-led formal network for vector control tools and interventions in PNG

Malaria rates are increasing in PNG and elsewhere in Melanesia.  LLINs are necessary but will not be sufficient on their own to reverse this trend and move towards elimination. Recent studies have also shown a decline in the effectiveness of LLINs in PNG and -in some areas- low net usage two years after mass distribution. Coupled with the challenge of early, outdoor- biting mosquitoes, new tools and improved usage are needed to fill these gaps.

NATNAT is part of IVCC’s Indo-Pacific Initiative (IPI) which is building on experience of vector control innovation in sub-Saharan African to identify and scale-up use of new and existing tools to support malaria control and elimination in the Indo-Pacific.   IVCC is facilitating direct dialogue between its Africa-based staff and the NATNAT team to provide lessons learned and best practice with implementation planning and training of spray operators, based on years of field experience.

IPI also complements IVCC’s focus on Africa through contributing to evidence on the performance of outdoor tools for use in last-mile elimination scenarios, as well as expanding the markets for other novel products such as 3^rd generation IRS.

NATNAT is one of three projects IVCC is leading in the Indo-Pacific region, funded by Australia Aid as part of its Global Health Security Initiative. The other two projects are Project BITE and a mathematical modelling project to predict the impact of new tools in the region.

Considering the significant challenges caused by COVID-19, IVCC commends its NATNAT partners for achieving this milestone on the road towards a possible reintroduction of national IRS spraying in PNG.