Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, USA.
Malaria Pathogenesis Unit, Eijkman Institute for Molecular Biology, Jakarta, Indonesia.
Malar J. 2024 Jan 30;23(1):37. doi: 10.1186/s12936-024-04856-8.
A major challenge to malaria elimination is identifying and targeting populations that are harbouring residual infections and contributing to persistent transmission. In many near-elimination settings in Southeast Asia, it is known that forest-goers are at higher risk for malaria infection, but detailed information on their behaviours and exposures is not available.
In Aceh Province, Indonesia, a near-elimination setting where a growing proportion of malaria is due to Plasmodium knowlesi, a case-control study was conducted to identify risk factors for symptomatic malaria, characteristics of forest-goers, and key intervention points. From April 2017 to September 2018, cases and controls were recruited and enrolled in a 1:3 ratio. Cases had confirmed malaria infection by rapid diagnostic test or microscopy detected at a health facility (HF). Gender-matched controls were recruited from passive case detection among individuals with suspected malaria who tested negative at a health facility (HF controls), and community-matched controls were recruited among those testing negative during active case detection. Multivariable logistic regression (unconditional for HF controls and conditional for community controls) was used to identify risk factors for symptomatic malaria infection.
There were 45 cases, of which 27 were P. knowlesi, 17 were Plasmodium vivax, and one was not determined. For controls, 509 and 599 participants were recruited from health facilities and the community, respectively. Forest exposures were associated with high odds of malaria; in particular, working and sleeping in the forest (HF controls: adjusted odds ratio (aOR) 21.66, 95% CI 5.09-92.26; community controls: aOR 16.78, 95% CI 2.19-128.7) and having a second residence in the forest (aOR 6.29, 95% CI 2.29-17.31 and 13.53, 95% CI 2.10-87.12). Male forest-goers were a diverse population employed in a variety of occupations including logging, farming, and mining, sleeping in settings, such as huts, tents, and barracks, and working in a wide range of group sizes. Reported use of protective measures, such as nets, hammock nets, mosquito coils, and repellents was low among forest-goers and interventions at forest residences were absent.
Second residences in the forest and gaps in use of protective measures point to key malaria interventions to improve coverage in forest-going populations at risk for P. knowlesi and P. vivax in Aceh, Indonesia. Intensified strategies tailored to specific sub-populations will be essential to achieve elimination.
消除疟疾的一个主要挑战是确定和针对那些携带残留感染并持续传播的人群。在东南亚许多接近消除疟疾的地区，已知森林居民感染疟疾的风险更高，但关于他们的行为和暴露的详细信息尚不清楚。
在印度尼西亚亚齐省，这是一个接近消除疟疾的地区，越来越多的疟疾是由间日疟原虫引起的，开展了一项病例对照研究，以确定有症状疟疾的危险因素、森林居民的特征以及关键的干预点。从 2017 年 4 月至 2018 年 9 月，招募了病例和对照，并以 1:3 的比例纳入研究。病例是在医疗机构（HF）通过快速诊断检测或显微镜检测确认的疟疾感染。性别匹配的对照是从医疗机构中疑似疟疾患者中被动病例检测中招募的（HF 对照），社区匹配的对照是从主动病例检测中检测为阴性的人群中招募的。采用多变量逻辑回归（HF 对照为无条件，社区对照为条件）来确定有症状疟疾感染的危险因素。
共发现 45 例病例，其中 27 例为间日疟原虫，17 例为间日疟原虫，1 例未确定。对于对照，分别从医疗机构和社区招募了 509 名和 599 名参与者。森林暴露与疟疾高发病率相关；特别是在森林中工作和睡觉（HF 对照：调整后的优势比（aOR）21.66，95%CI 5.09-92.26；社区对照：aOR 16.78，95%CI 2.19-128.7）和在森林中有第二个住所（aOR 6.29，95%CI 2.29-17.31 和 13.53，95%CI 2.10-87.12）。男性森林居民是一个多样化的群体，从事各种职业，包括伐木、农业和采矿，他们在小屋、帐篷和营房等环境中睡觉，工作规模大小不一。森林居民报告使用的保护措施（如蚊帐、吊床网、蚊香和驱虫剂）使用率较低，而且在森林住所没有采取干预措施。
森林中的第二个住所以及保护措施使用方面的差距，为印度尼西亚亚齐提高森林居民对间日疟原虫和间日疟原虫的覆盖率提供了关键的疟疾干预措施。针对特定亚人群的强化策略对于实现消除疟疾至关重要。
