Molecular Characterization and Phylogenetic Analysis of Flea Species in Human and Livestock Residence by Targeting ITS2 Region in East Azerbaijan Province, Iran.

Background: Fleas are blood-sucking ectoparasites with complete metamorphosis. They belong to the order Siphonaptera and can infest both humans and animals, causing dermatitis and transmitting vector-borne diseases. Despite extensive study of their classification and biology, the phylogenetic relationship between fleas in Iran is not fully understood. This research aimed to identify the flea species collected from different parts of East Azerbaijan Province in northwest Iran, using morphological, molecular, and phylogenetic analysis.

Methods: From October 2019 to October 2020, we collected fleas using various methods such as hand catching for humans, brushing for dogs and cats, sticky traps for rodent burrows, light traps, and dishes with water for sheep and goats. After identifying the flea species using morphological identification keys, we extracted total genomic DNA and amplified it by targeting the ITS2 region. The PCR products were then directly sequenced to investigate the flea species.

Results: In total, 1929 flea specimens were collected, revealing three genera and four species. The breakdown of the specimens is as follows: Pulex irritans (n=1206; 62.5%), Ctenocephalides canis (n=345; 18%), Ctenocephalides felis felis (n=203; 10.5%), Ctenocephalides felis orientis (n=160; 8%), and Xenopsylla nuttalli (n=15; 1%). Phylogenetic analysis indicated low to moderate haplotype diversity (Hd: 0-0.524) across five distinct clades: P. irritans, C. canis, C. felis felis, C. felis orientis, and X. nuttalli.

Conclusion: This study represents the first in-depth analysis in East Azerbaijan Province, highlighting the significance of considering P. irritans as a major vector when assessing the risk of local disease transmission.