Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand.
Inform Asia: USAID's Health Research Program, RTI International, Bangkok, Thailand.
Malar J. 2021 Feb 27;20(1):118. doi: 10.1186/s12936-021-03648-8.
Thailand's success in reducing malaria burden is built on the efficient "1-3-7" strategy applied to the surveillance system. The strategy is based on rapid case notification within 1 day, case investigation within 3 days, and targeted foci response to reduce the spread of Plasmodium spp. within 7 days. Autochthonous transmission is still occurring in the country, threatening the goal of reaching malaria-free status by 2024. This study aimed to assess the effectiveness of the 1-3-7 strategy and identify factors associated with presence of active foci.
Data from the national malaria information system were extracted from fiscal years 2013 to 2019; after data cleaning, the final dataset included 81,012 foci. A Cox's proportional hazards model was built to investigate factors linked with the probability of becoming an active focus from 2015 to 2019 among foci that changed status from non-active to active focus during the study period. We performed a model selection technique based on the Akaike Information Criteria (AIC).
The number of yearly active foci decreased from 2227 to 2013 to 700 in 2019 (68.5 %), and the number of autochthonous cases declined from 17,553 to 3,787 (78.4 %). The best Cox's hazard model showed that foci in which vector control interventions were required were 18 % more likely to become an active focus. Increasing compliance with the 1-3-7 strategy had a protective effect, with a 22 % risk reduction among foci with over 80 % adherence to 1-3-7 timeliness protocols. Other factors associated with likelihood to become or remain an active focus include previous classification as an active focus, presence of Plasmodium falciparum infections, level of forest disturbance, and location in border provinces.
These results identified factors that favored regression of non-active foci to active foci during the study period. The model and relative risk map align with the national malaria program's district stratification and shows strong spatial heterogeneity, with high probability to record active foci in border provinces. The results of the study may be useful for honing Thailand's program to eliminate malaria and for other countries aiming to accelerate malaria elimination.
泰国在降低疟疾负担方面取得成功，这得益于应用于监测系统的高效“1-3-7”策略。该策略基于在 1 天内迅速通报病例、在 3 天内进行病例调查以及针对目标焦点进行有针对性的应对，以在 7 天内减少疟原虫属的传播。该国仍存在本土传播，威胁到 2024 年实现无疟疾状态的目标。本研究旨在评估 1-3-7 策略的有效性，并确定与存在活跃焦点相关的因素。
从 2013 年至 2019 年的国家疟疾信息系统中提取数据；在数据清理后，最终数据集包括 81012 个焦点。建立 Cox 比例风险模型，以调查在研究期间从非活跃焦点转变为活跃焦点的焦点中，2015 年至 2019 年期间，与成为活跃焦点的概率相关的因素。我们基于赤池信息量准则（AIC）进行了模型选择技术。
每年活跃焦点的数量从 2013 年的 2227 个减少到 2019 年的 700 个（68.5%），本土病例数量从 17553 例减少到 3787 例（78.4%）。最佳 Cox 风险模型显示，需要进行媒介控制干预的焦点成为活跃焦点的可能性增加了 18%。增加对 1-3-7 策略的遵守具有保护作用，在遵守 1-3-7 及时性协议超过 80%的焦点中，风险降低了 22%。与成为或保持活跃焦点的可能性相关的其他因素包括先前被分类为活跃焦点、存在恶性疟原虫感染、森林干扰程度以及位于边境省份。
这些结果确定了在研究期间有利于非活跃焦点向活跃焦点回归的因素。该模型和相对风险图与国家疟疾规划的区划分层一致，并显示出强烈的空间异质性，在边境省份记录活跃焦点的概率很高。研究结果可能有助于泰国消除疟疾计划的完善，并为其他旨在加速消除疟疾的国家提供参考。
