Demographic and Epidemiological Patterns of Reported Malaria Cases in Aseer Region, Saudi Arabia: An Eight-Year Surveillance Analysis

Background Despite substantial progress toward malaria elimination in Saudi Arabia, imported infections continue to threaten re-establishment of transmission, particularly in southwestern regions. Aseer Region, contains diverse ecological settings that may support malaria vectors. This study examined the demographic and epidemiological characteristics of malaria cases reported in Aseer between 2016 and 2023. Methods A retrospective surveillance analysis of malaria surveillance records was conducted using data from the Vector Diseases Control Unit of the Ministry of Health. All laboratory-confirmed malaria cases reported from January 2016 to December 2023 were included. Demographic variables and malaria species were analyzed. Cases were classified as imported, introduced, or local according to World Health Organization definitions. Descriptive and inferential statistical analyses were performed using R software, and spatial distribution was mapped using QGIS. Results A total of 1,254 laboratory-confirmed malaria cases were identified during the study period. Annual case numbers declined from 266 in 2016 to 63 in 2018 before increasing to 343 cases in 2023. Imported infections accounted for 799 cases (63.7%), followed by local (303, 24.2%) and introduced cases (152, 12.1%). Case classification varied significantly by year (χ²=570.54, df=14, p<0.001). Males represented 84.4% of cases, and the median age was 26 years, with the highest burden among individuals aged 25–34 years (32.9%) and 15–24 years (31.0%). Non-Saudi nationals accounted for 65.1%, with Ethiopian, Sudanese, and Yemeni. Plasmodium falciparum was the predominant species (75.2%), followed by P. vivax (24.3%). In multivariable analysis, nationality and P. vivax infection were independently associated with importation-related malaria, whereas sex was not. Conclusion Malaria in Aseer during 2016–2023 was characterized by fluctuating incidence, increasing predominance of importation-related infections. Multivariable analysis identified non-Saudi nationality and P. vivax infection as factors associated with importation-related malaria. Sustained surveillance, targeted interventions for mobile populations, and continued vector control are essential to prevent re-establishment of indigenous malaria transmission and support national elimination goals.