Ecological and faunistic features of fleas in the Transcaucasian mounthill natural plague foci in Azerbaijan

Among all vectors of natural focal infections, fleas are the most active. In this respect, entomological and epizootological monitoring has always been of great importance. This article, based on the material collected from the Transcaucasian foothill natural plague focus, presents the results of a study of flea species diversity, the landscape and geographical area of their distribution. The goal of this work was to determine the diversity of flea species, their distribution and abundance based on the results of epizootological studies conducted in areas with different landscapes in the Transcaucasian foothill natural plague focus of Azerbaijan. The material for the study was obtained during epizootological studies and observations conducted in the spring and autumn seasons of 2020–2023. in the Transcaucasian foothill natural plague focus of Azerbaijan (Bozchol, Mil-Mugan, Eastern and Western Jeyranchel, Gobustan, Absheron, semi-deserts of Kilazi, Sitalchay). Collection, packaging, transportation, and marketing of the material were carried out on the basis of relevant biosafety rules and delivered for further study to the Special Dangerous İnfections Control Center. In total, 61,087 nest tracks were examined, and 7,939 fleas were collected and delivered. The material was processed and identified in the laboratory in accordance with the current regulatory and methodological document on the safety of working with pathogenic biological agents (PBA) of pathogenicity groups I–IV. As a result of sample identification, the species composition of fleas was determined and grouped by geographical areas and landscapes. Research was also carried out (using the PCR method) for the presence of the plague causative agent - Yersinia pestis. According to the results of the study, it was found that, regardless of the biocenotic and climatic characteristics of individual sectors of the Transcaucasian foothill natural plague focus of Azerbaijan, there may be enough carriers of infectious diseases and their growth increases over the years. The frequency of occurrence of the prevailing genera of fleas - Xenopsylla and Nosopsyllus- depends on the natural and climatic conditions of the focus being studied. The analysis for the presence of the plague causative agent among all fleas caught and studied did not give positive results. For the timely detection of epizootics among wild rodents and bloodsuckers, it is important to conduct regular epizootic surveys in enzootic areas for plague.