Association between immigrant population size and malaria prevalence and foci status in southern Iran

Abstract Objective This study examined the association between immigrant population size and malaria prevalence and foci classification in southern and southeastern Iran. Methods A cross-sectional study was conducted across four provinces, including 522 health centers in 38 cities. Data were collected between April and September 2019. The unit of analysis was the population covered by the health centers. Data were obtained from standardized foci-classification checklists and analyzed using Spearman correlation and logistic regression in SPSS version 21. Immigrant population size was categorized into prespecified groups of 0, 1–50, 51–100, and > 100 individuals. Results As the immigrant population size increased, the proportion of new active malaria foci rose from 4.0% to 15.9%. The number of malaria cases showed a weak positive correlation with Afghan immigrant population size ( r = 0.24, p < 0.001) and a moderate positive correlation with Pakistani immigrant population size ( r = 0.46, p < 0.001). Compared to health centers with no immigrants, the adjusted odds ratio of positive malaria cases increased from 19.68 ( p = 0.005) for 1–50 to 30.36 ( p = 0.001) for more than 100 immigrants. Conclusion The findings suggest that the immigrant population size was associated with malaria risk indicators in southern Iran. These results emphasize the epidemiological importance of population mobility in malaria‑elimination settings and provide supportive evidence for considering immigrant population dynamics when evaluating malaria risk patterns.