Work

An integrated approach to prioritizing areas for imported malaria re-establishment prevention in Chongqing, China

Year: 2026

Type: article

Abstract: Objective This study integrated spatiotemporal analysis of imported malaria cases, ecological niche modeling of Anopheles sinensis , and field-measured vector density to prioritize county-level areas for imported malaria re‑establishment prevention in Chongqing, China. The findings facilitate a stratified and targeted response strategy, thereby providing evidence-based guidance for mitigating the risk of re-establishment arising from imported cases. Methods Data on imported malaria cases in Chongqing (2014–2024) and vector surveillance records were compiled for this study. The vector data comprised two components: occurrence records (2011–2025) for ecological niche modeling and quantitative density measurements (2011–2024) for priority mapping, with density expressed as captures per trap-night during the peak mosquito activity season (June–October). Spatiotemporal pattern analysis was performed using R 4.5.2. Based on the vector data, ecological niche modeling was implemented via biomod2 (v.3.5.1), whereas all spatial operations—including map overlays and priority zoning—were conducted in ArcGIS 10.8. Results Of the 301 imported malaria cases documented in Chongqing during 2014–2024, 75.08% were attributed to P. falciparum and 12.29% to P. vivax . The affected population was predominantly male (94.35%), aged 21–50 years (84.71%), and predominantly composed of outbound migrant workers (60.80%). Cases originated from 32 African countries (90.37%), with the Democratic Republic of the Congo and Nigeria accounting for the highest proportions. Spatially, cases were mainly clustered in the metropolitan area and western districts. Among the 39 P. vivax cases (including mixed infections), relative concentrations were observed in Yubei, Hechuan, and Pengshui, and 20 (51.28%) were reported during the peak mosquito activity season (June–October). The ensemble niche model for An. sinensis identified bio5, NDVI and bio11 as the leading environmental determinants, with predicted suitable habitats largely concentrated in the metropolitan and western areas. Field surveillance revealed substantial spatial heterogeneity in vector density, with the highest densities recorded in Wanzhou, followed by Yunyang, Fengjie, and Fengdu, whereas densities in the metropolitan districts were uniformly low except in Jiulongpo. Conclusions Suitable habitats for An. sinensis were predicted across most of Chongqing, yet imported cases were primarily concentrated in the metropolitan area and western Chongqing. After further overlaying imported P. vivax cases and empirical vector density data. Wanzhou, Yubei, Hechuan, Tongnan, Pengshui, and Jiulongpo were identified as top-priority districts, whereas Tongliang, Shapingba, Jiangjin, Yongchuan, Dazu, Rongchang, Fuling, Wulong, Xiushan, Zhongxian, and Wushan were classified as moderate-priority districts. Enhanced surveillance should be prioritized to ensure timely detection and standardized clinical management of imported cases, coupled with vector suppression during the peak mosquito activity season—so as to eliminate opportunity for re-establishment.

Source: Frontiers in Cellular and Infection Microbiology

DOI: 10.3389/fcimb.2026.1929309