Table 1.
Selected Malaria Characteristics From Included Studies
| Location and References | Population Type | Study Type | Objectives | Recommended Policy | Challenges and Opportunities |
|---|---|---|---|---|---|
| Cambodia: Gryseels et al, (2015) [39]; Durnez et al (2013) [40]; Bannister-Tyrell et al (2019) [41] | Forest-goers from 113 of the high-endemic villages in Ratanakiri Province (MalaResT Trial); people living in or near the forest fringe that use the forest for economic activities | Mixed method at 2 time points; sequential mixed-methods: quantitative survey research methods used to complement findings from qualitative ethnographic research; qualitative ethnographic | Ancillary work in larger trial to determine the effectiveness of mass use of topical repellents in addition to use of LLINs in controlling transmission as measured by community impact; understand how different populations, mobility, livelihood patterns, and activities within the forest intersect to potentiate malaria risk and affect the effectiveness of malaria control and elimination strategies | Reimagining malaria interventions by focusing not only on the heterogeneity in malaria transmission, but more specifically on the connection between varying human and vector behaviors, evaluate what works; what is still missing, and how to accelerate the progress in malaria control toward elimination; as forest groups often converge in the same areas, interventions targeting the vector population may have a potential role; ultimately, a multisectoral approach as well as innovative and flexible malaria control strategies are required for malaria elimination efforts to be successful | Transmission due to early and outdoor biting is among the major challenges; slash-and-burn farmers’ multiple residence system, locally used (partially) open housing structures, variance in labor and social activities, sleeping times, and bed net use; movement between different houses with varying levels of exposure to indoor and outdoor mosquito biting results in a constantly changing vulnerability to malaria; reported sleeping times vary according to the context; additional gaps in night protection, however, cannot be addressed with LLINs alone (eg, outdoor economic forest activities and toilet practices); most forest-goers had experienced multiple episodes of malaria and are well informed about malaria risk, but economic realities drive local residents to pursue forest-based livelihoods; severe constraints of available vector control methods mean forest-goers have limited capacity to prevent vector exposure; as they access the forest using many different entry and exit points, border screening and treatment interventions may not be feasible |
| Xieng-Ngeun and Nane districts, Luang Prabang Province, Lao PDR: Tangena et al (2017) [42] | Subsistence farmers and forest-goers | Rapid participatory rural appraisals and surveys with entomological surveillance | Assess the risk of exposure to vector mosquitoes in relation to different typologies of human behavior | Local people using DEET-based topical repellent, long clothing, and mosquito coils; medium risk of transmission in rubber plantations based on PSI work in Lao/Vietnam [43] | Visiting forests during the day has a higher risk of malaria vector exposure, but risk does not increase when working and living in the rubber plantations; need to broaden current vector control activities to include rubber plantations very near forests |
| Tha Song Yang District, Tak Province, Thailand: Edwards et al (2019) [44] | Forested foothills, subsistence farming, slash-and-burn agriculture beyond the villages | Cross-sectional behavior and net survey, observational and entomological collections in 2 villages and forested farm huts | Investigate the magnitude of RMT and contributing risk factors | Provide access to LLINs beyond village to farm huts and forest locations that are frequently visited by community members as these have a higher abundance of vectors and highest-risk practices | Novel personal protection tools that require minimal behavioral change and are accessible/affordable for the target populations (eg, = insecticide-treated blankets and clothing, spatial and topical repellents); use of entomological end points to show efficacy in low-transmission settings and acceptance of such tools in elimination strategies |
| Khanh Vinh District, Khanh Hoa Province, Vietnam: Edwards et al (2019) [45] | Subsistence farmers in rural villages and upland forest foothills practicing seasonal farming, slash-and-burn agriculture beyond the village | Entomological, epidemiological, and observational methods across 3 ecological sites frequented by village community, farm huts, and forest waypoints | Investigate how vector and human behaviors interact to contribute to RMT in an area poised for malaria elimination | Improve access to LLIHNs among forest-goers at risk of malaria and other vector-borne diseases through public-private partnerships | Evaluate new personal protection tools that will minimize behavior change, and highly accessible/feasible for use by population |
| Dabhine and Myothugyi areas, Rakhine State, Myanmar: Smithuis et al (2013) [46] | Cohort of 8175 children <10 y old from 22 villages | Cluster-randomized controlled trial to assess effectiveness of ITNs among 8175 children <10 y of age for 10 mo | Conduct entomological and population sleeping behavior surveys alongside multivillage ITN effectiveness study; observe incidence and prevalence of Plasmodium falciparum and Plasmodium vivax infections and the biting behavior of Anopheles vectors | Prioritize provision and access to early diagnosis and effective treatment; where such services are already in place and sufficient budgets available, including use of ITN can be a cost-effective integrated approach for control | Where malaria transmission is highly seasonal and unstable showing spatiotemporal variation, ITNs do not provide consistent protection against malaria in areas with weak secondary vectors; all major Anopheles vectors are characterized by early and outdoor biting, often before people are protected by an ITN |
| Malaysia: Kudat District, Sabah Barber et al (2013) [47]; Chua et al (2019) [48]; Grigg et al (2017) [30] | Secondary forest and small plantations of coconut, rubber, or oil palm; local swidden farming as primary occupation | Case-control, prospective clinical study to compare malaria risk factors, clinical spectrum, and outcome of severe disease by human and simian malaria, entomological and programmatic reports | Case-control study to assess human and environmental factors associated with zoonotic Plasmodium knowlesi malaria risk; entomological investigation to determine diversity and abundance of vector species in the 5 habitat types commonly found in rural areas of Sabah | Individual-level factors affecting zoonotic P. knowlesi transmission in established endemic areas are potential targets for future public health interventions, along with ongoing promotion of conventional malaria prevention activities | Novel tools are needed to address outdoor farming, vegetation clearing or plantation work, older males, sleeping outside, and travel history—for example, outdoor residual spray using a novel formulation of deltamethrin K-Othrine (PolyZone) (Rohani et al [2020] [49]) |
| Papua New Guinea: Rodriguez-Rodriguez et al (2019) [50] and Rodriguez et al (2019) [51] | Coastal island atolls, lowland and highland populations from southern, Momase, islands, and highland regions | Mixed methods: cross-sectional malaria indicator survey (quantitative) and in-depth interviews and focus group discussions (qualitative) | Assess the role of human behavior in relation to malaria transmission and transmission heterogeneities by (1) identifying activities and livelihood relevant for malaria transmission, (2) understanding measures currently in use to prevent or reduce mosquito biting in the study sites, and (3) identifying behavioral differences between population groups | Study highlighted the potential of “outdoor biting” that can hamper malaria control and elimination efforts if not addressed appropriately because people spend a remarkable amount of time outdoors without protection from mosquito biting; complementary interventions to LLINs targeting groups, places and activities in order to prevent outdoor biting in the evening and understanding local community behavior are crucial to advance elimination | Need to integrate main study findings with concurrent entomological and malaria infection prevalence data to quantify behavioral risk factors of exposure and better quantify local transmission; given diverse transmission settings in PNG, the national control program must consider local heterogeneity when choosing interventions and ensure continuous monitoring of trends |
| East Sepik Province, Papua New Guinea: Kattenberg et al (2020) [52] | Wet tropical low hill forests, plains, riverine plains; rural villages (n = 2231 [2005] and n = 2348 [2013]) | Cross-sectional community surveys, pre- and postimplementation observations using malaria prevalence; 2005: 73%; 2012–2013: 12.2% | Assess impact on malaria prevalence with control focused on mass distribution of LLINs | To further reduce transmission, additional surveillance approaches, novel tools and community engagement strategies may need to be combined with sustained LLIN coverage and effective malaria case management; understanding local heterogeneity and the key parameters (eg, LLIN coverage/use, socioeconomic factors, vector behavior, environmental factors) that drive transmission is essential to designing and implementing site-specific control strategies | Despite strengthening the MCP in Papua New Guinea and showing a substantial decrease in malaria prevalence, areas with high ongoing transmission remain; given local heterogeneity of transmission, identification and targeting focal points of persistent RMT are needed including development of sensitive and practical surveillance tools to identify and target high-malaria areas and households |
| Central Island Province, Solomon Islands: Pollard et al (2020) [53] | Coastal villagers—primarily subsistence agriculture and fishing | Experimental, observational, interviews and movement diaries | Study of people over a 14-d period and quantifying human-vector interactions where and when humans are exposed to the bites of vectors | IRS should include outdoor kitchens and verandas in addition to standard applications to inside walls; alternatively, novel control methods such as insecticide-treated durable wall linings, spatial repellents, insecticidal paints, and screening to mosquito-proof verandas and kitchens should be evaluated | Despite excellent access and near-universal use of indoor LLINs, a large protection gap exists with people exposed in the outdoor peridomestic area when many malaria mosquitoes are seeking blood meals |
Abbreviations: DEET, N,N-diethyl-meta-toluamid; IRS, indoor residual spray; ITN, insecticide-treated bed net; LLIHNs, long-lasting insecticidal hammock nets; LLIN, long-lasting insecticidal net; MCP, Malaria Control Program; PDR, People’s Democratic Republic; PNG, Papua New Guinea; PSI, Population Services International; RMT, residual malaria transmission.