Investigation of Fauna, Seasonal Activity of Sand Flies, Determination of Leishmaniasis Vectors, and Human Infection Through Molecular Methods in Bastak, Hormozgan Province, 2021

<b><i>Background:</i></b> Cutaneous leishmaniasis (CL) is one of the most common vector-borne diseases worldwide and is prevalent in many parts of Iran. Phlebotomine sand flies act as vectors, transmitting the parasite through blood feeding on infected hosts. This study aimed to identify the fauna and seasonal activity of sand flies and to detect <i>Leishmania</i> DNA in vectors and human samples in rural areas of Bastak County, southern Iran, in 2021. <b><i>Materials and Methods:</i></b> A cross-sectional survey was conducted from March 2020 to February 2021. Sand flies were collected indoors and outdoors every 15 days using sticky traps. After morphological identification and activity assessment, DNA was extracted from a subset of sand flies and from human lesion samples. PCR was applied to detect the presence of <i>Leishmania</i> parasites. <b><i>Results:</i></b> A total of 2,747 sand flies were collected and identified. Activity showed two peaks, one in early March and another in early October. Eleven species were recorded, including four <i>Phlebotomus</i> and seven <i>Sergentomyia</i> species. <i>Phlebotomus alexandri</i> was the most abundant (49.1%). No <i>Leishmania</i> DNA was detected in captured sand flies, whereas human samples revealed PCR bands (650 bp) consistent with <i>L. major</i>. <b><i>Conclusion:</i></b> The presence of <i>P. alexandri</i> and <i>P. papatasi</i> as dominant species highlights their potential epidemiological importance in Bastak County. These findings provide baseline information on sand fly fauna and activity, emphasizing the need for continued entomological surveillance and molecular monitoring to better understand leishmaniasis transmission in the region.