Risk factor assessment for clinical malaria among forest-goers in a pre-elimination setting in Phu Yen Province, Vietnam

Abstract

BackgroundThe transition from malaria control to elimination requires understanding and targeting interventions among high-risk populations. In Vietnam, forest-goers are often difficult to test, treat and follow-up for malaria because they are highly mobile. If undiagnosed, forest-goers can maintain parasite reservoirs and contribute to ongoing malaria transmission.MethodsA case–control study was conducted to identify malaria risk factors associated with forest-goers in three communes in Phu Yen Province, Vietnam. Cases (n = 81) were residents from the study area diagnosed with malaria and known to frequent forest areas. Controls (n = 94) were randomly selected forest-going residents from within the study area with no identified malaria infection. Participants were interviewed face-to-face using a standard questionnaire to identify malaria risk factors. Logistic regression was used to calculate odds ratios (ORs) and 95% CI for risk factors after adjusting for socio-demographic characteristics.ResultsAmong the cases, malaria infection varied by species: 66.7% were positive for Plasmodium falciparum, 29.6% for Plasmodium vivax, and 3.7% were diagnosed as mixed infection. Cases were less likely than controls to use treated nets (aOR = 0.31; 95% CI 0.12–0.80), work after dark (aOR = 2.93; 95% CI 1.35, 6.34), bath in a stream after dark (aOR = 2.44; 95% CI 1.02–5.88), and collect water after dark (aOR = 1.99; 95% CI 1.02–3.90).ConclusionsAs Vietnam moves toward malaria elimination, these findings can inform behaviour change communication and malaria prevention strategies, incorporating the risk of after-dark and water-related activities, in this priority and difficult-to-access population group.

Forest malaria: the prevailing obstacle for malaria control and elimination in India

“…The communities inhabiting these are often resistant to medical advice. 10 , Thus despite the considerable decline in India’s malaria prevalence, the forested areas are still the major contributors to the total malaria cases despite their low population ( figure 2B, C ). The significant decrease in malaria in India in the past ~5 years is contrasted by lower declines in forested districts ( figure 2B ).…”

“… 9 Communities living in forests are also the most challenging to test, treat and follow-up. 10 Due to the ambient conditions for transmission and difficulties in control efforts in the forest ecosystems, it is of immense importance to focus on these areas for the ongoing control efforts. Despite being malaria hotspots, no analysis has been attempted so far on delineating the different malaria scenario in forested areas, and the strategic relevance of focusing on these malarious hotspots in India.…”

Malaria Knowledge and Infection Among Migrant Population in the China-vietnam Border: A Questionnaire-based Survey

“…For Vietnam, the high risk of migrant population was proposed as forest goers, who may live in forest borer regions and have poor knowledge of malaria and limited access to preventive and therapeutic services [15,16]. As malaria transmission decline in Vietnam, the high prevalence of asymptomatic and sub-microscopic infections was the main challenge [17][18][19][20]. Asymptomatically infected individuals usually do not seek treatment and generally harbour low parasite density undetectable with microscopy examination.…”

Mosquito Net Ownership, Utilization, and Preferences among Mobile and Migrant Populations Sleeping in Forests and Farms in Central Vietnam: A Cross-Sectional Study

“…This cross-sectional survey conducted between August and September 2016 was part of a larger, detailed malaria survey within the study area. 27 , 28 Of the 4,668 households that were recorded and mapped in 18 villages within the three study-site communes, 1,083 households were randomly selected for inclusion in the survey. A semi-structured interviewer-administered questionnaire was developed based on a literature review of malariometric surveys and with input from the research team.…”