Suitable ecological niches of invasive malaria vector under present and projected climatic conditions in South of Iran

BACKGROUND: The invasive mosquito species Anopheles stephensi plays a critical role in malaria transmission, particularly in urban environments. Its ability to thrive in such settings has raised public health concerns, especially as it expands its geographical range. The resurgence of malaria in Iran underscores the challenges posed by this vector, which is further complicated by factors such as climate change and the movement of populations. Understanding the ecological niches of An. stephensi is essential for developing targeted malaria control strategies. This study aims to assess the current and projected distribution of An. stephensi in Hormozgan Province, Iran, under varying climatic conditions. METHOD: The study was conducted in Hormozgan Province, Iran, characterized by a hot, arid climate. A database of 96 occurrence points for An. stephensi was compiled through literature searches, which were refined to 72 points to ensure data quality. Environmental and bioclimatic data were sourced from the WorldClim v2.1 database, with a focus on various Shared Socioeconomic Pathways (SSPs). The MaxEnt modeling technique was employed to assess the impact of climate change on the species' distribution, with model performance evaluated using the two metrics, Area Under the Curve (AUC) and True Skill Statistic (TSS). The analysis aimed to map shifts in suitable habitats under different climate scenarios. RESULTS: The MaxEnt model predicts a significant decline in environmental suitability for An. stephensi under future climate scenarios, particularly in western and central Hormozgan Province. Habitat loss is prevalent, with stable areas primarily located in Bashagard County. Factors such as altitude and precipitation patterns significantly influence species distribution, with altitude showing the highest impact. The model's performance, indicated by an average AUC of 0.765 and a TSS of 0.519, demonstrates moderate predictive accuracy for identifying suitable habitats. DISCUSSION: Despite advancements in malaria control, An. stephensi remains a significant threat in Iran, particularly due to its invasive nature and adaptability to climate change. The study indicates a projected decline in suitable habitats, especially in coastal areas, highlighting the need for adaptive vector control strategies. Bashagard County may serve as a stable refuge, warranting further investigation. The findings emphasize the importance of continuous monitoring and integrating climate projections into public health interventions to effectively combat malaria transmission. Overall, ongoing research is crucial to refining understanding and enhancing malaria control efforts in response to shifting environmental conditions.