: The tribal population in and around the Western Ghats region of India is affected by both cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) with typical clinical symptoms. In this study, we recorded and analyzed seven CL and three VL cases from this emerging belt. All the cases were found as autochthonous transmission. Multiple genetic markers (minicircle kinetoplast DNA polymerase chain reaction and restriction fragment length polymorphism of 3′untranslated region heat shock protein (HSP) 70, a larger segment of HSP 70, and 6-phosphogluconate dehydrogenase [PGDH] gene sequences) were used to identify and characterize the parasite. It was found that both clinical manifestations are caused by zymodeme MON-37 of Leishmania donovani. We have investigated the detailed entomological and epidemiological aspects of disease transmission. An abundant population of the proven vector Phlebotomus argentipes was observed in the study villages.

Phlebotomus argentipes is the predominant sandfly vector of leishmaniasis in the Indian subcontinent. India and Sri Lanka primarily report visceral and cutaneous leishmaniasis caused by Leishmania donovani. We compared Ph. argentipes from two locations, focusing on its morphological, molecular, and salivary protein characteristics. Sandflies were captured using CDC light traps and cattle-baited net traps. Species identification and morphological comparisons were carried out using standard taxonomic keys. DNA extracted from 12 Sri Lankan sandfly samples was PCR-amplified and sequenced for the variable region of Cytochrome oxidase subunit I. Existing DNA sequences of India from GenBank were utilized for a phylogenetic analysis between Sri Lanka and India. Salivary protein profiles were studied using SDS-PAGE, Western blot, and electrospray ionization/LC/MS/MS. The morphological similarities observed between female Ph. argentipes from India and Sri Lanka suggest the presence of Ph. argentipes var. glaucus. A phylogenetic analysis showed genetic divergence between Ph. argentipes populations, but both shared a similar salivary protein profile. A common, strong 30 kDa immunogenic band comprised PagSP05, PagSP06, and PagSP17 proteins of Ph. argentipes. The similarity between the immunogenic salivary proteins suggests their potential use as common markers for vector exposure or immune response stimulants across regions. The use of multiple samples for each category of serum would improve the comprehensiveness of the immunogenic profiles obtained.

Madhya Pradesh, a biodiversity-rich state in central India, reports sporadic non-indigenous leishmaniasis cases. Systematic entomological surveillance as part of molecular xenomonitoring in sand flies led to the discovery of a new species, Sergentomyia (Neophlebotomus) pradeepii n. sp. (Diptera: Psychodidae), from Johariya village in Sagar district, Madhya Pradesh, India. A systematic cross-sectional survey of sand flies was conducted in Bhopal, Sagar, and Hoshangabad districts of Madhya Pradesh. Standard collection methods were employed for two months, i.e., from July to August 2023. DNA barcoding targeting the mitochondrial Cytochrome c oxidase subunit I (COI) gene was performed, and the generated sequences were phylogenetically analyzed. Se. (Neo.) pradeepii, a newly recorded sand fly species, is reported in this study. Its taxonomic relationship to other congeners of subgenus Neophlebotomus is discussed. COI barcoding and phylogenetic analysis established that the specimens fit into the same taxonomic group, exhibiting negligible gene flow within the population, while a 13.4% genetic distance from congeners establishes it as a separate species. Madhya Pradesh, with its rich biodiversity and favorable conditions for sand fly proliferation, lacks systematic entomological surveillance. This study enhances the knowledge of the state’s sand fly fauna by reporting and providing a detailed morphological and molecular description of the new species.

The Western Ghats of Keralam is a globally recognized biodiversity hotspot, yet information on sand fly (Diptera: Psychodidae) vectors of leishmaniasis from this region remains limited. They play a central role in the transmission of leishmaniasis, a major neglected tropical disease of public health importance in India. This study aimed to generate comprehensive entomological and ecological evidence on sand fly diversity, distribution, and Leishmania infection in the Western Ghats region of Keralam, India. A cross-sectional entomological survey combined with xenomonitoring was conducted between 2021 and 2024 across nine districts of Keralam. Sand flies were collected from indoor, peri-domestic, and outdoor habitats using standard collection methods and analyzed for species composition, habitat preference, seasonal trends, and associations with environmental variables including temperature, rainfall, humidity, and altitude. Biodiversity indices were calculated, and female Phlebotomus argentipes were screened for Leishmania kinetoplast DNA (k-DNA). A total of 12,659 sand flies belonging to 22 species and four genera were collected. Peak abundance was recorded during May–June and September–October. Ph. argentipes was the dominant species, primarily associated with indoor and peri-domestic habitats. Mechanical aspirators yielded higher abundance and species diversity than light traps. Sand fly abundance was positively correlated with relative humidity (p < 0.001) and negatively correlated with altitude (p < 0.001), while species diversity declined significantly with increasing elevation (p = 0.029). The highest diversity was observed in central Keralam (Shannon H’= 2.371; Simpson λ = 0.879) and foothill regions (H’ = 2.328; λ = 0.873). Of 266 Ph. argentipes pools screened, five were positive for Leishmania k-DNA from four districts. This study provides a comprehensive entomological assessment of sand flies in Keralam’s Western Ghats, highlighting species diversity, seasonal patterns, habitat preferences, and Leishmania infection. The findings underscore the need for sustained, evidence-based entomological surveillance to support targeted vector control and advance India’s leishmaniasis elimination efforts.