Comprehensive New Information on the Distribution and Pathogenicity of Leishmaniasis, the Factors Causing Its Emergence in New Areas and Affecting Pathogenicity in Iran

Leishmaniasis is a neglected tropical disease caused by the Leishmania species. This comprehensive research has studied the distribution and pathogenicity of leishmaniasis and the factors causing its emergence in new areas and affecting pathogenicity in Iran. Eighty-seven documents were collected in the web search. With a diverse climate and geographical landscape, Iran is home to several Leishmania species, resulting in a significant health burden with various forms. The leishmaniasis distribution exhibits a complex pattern across Iran that is influenced by factors, like climate change, urbanization, and migration patterns. Poor sanitation infrastructure and inadequate access to safe water sources also contribute to the spread of leishmaniasis by creating favorable breeding conditions for vectors. Moreover, environmental changes such as deforestation and agricultural activities further facilitate vector habitat expansion. Leishmaniasis is prevalent in both rural and urban areas throughout Iran, with distinct regional variations in prevalence and intensity. Followed by visceral and mucocutaneous leishmaniasis, cutaneous leishmaniasis is the most prevalent form. Northern provinces, like Gilan and Mazandaran, experience lower incidence rates due to their colder climates and higher altitudes. In contrast, southern regions like Kerman and Fars display higher rates due to their arid environments and suitable breeding grounds for vectors. Additionally, the western provinces of Ilam and Khuzestan witness a significant disease burden due to their proximity to Iraq, where leishmaniasis is endemic. The pathogenesis of leishmaniasis involves a complex interplay between the parasite, host immune responses and environmental factors. Another important factor influencing pathogenicity is the vector species transmitting the parasite.