Principles and methods for isolating natural foci of zoonotic cutaneous leishmaniasis

Abstract

Zoonotic cutaneous leishmaniasis is a vector-borne disease with natural foci, prevalent in regions with arid and semi-arid climates, where the pathogen circulates among wild rodent reservoir hosts and sandflies serve as vectors. The persistence of natural foci poses a constant threat of infection to the human population, necessitating the development of evidence-based principles and methods for their isolation aimed at disrupting the pathogen transmission mechanism. The aim of this study was to investigate the formation characteristics of natural foci of zoonotic cutaneous leishmaniasis and to substantiate a set of measures for their isolation. A comprehensive approach was employed, involving an epizootiological survey of the area (assessing the abundance and infection rates of reservoir hosts), an entomological study of sandfly species composition and seasonal population dynamics, and a landscape-geographic analysis of the conditions defining the focus boundaries. Population morbidity was assessed based on healthcare utilization data and active case detection results, while the effectiveness of isolation measures was evaluated through longitudinal monitoring. The study results demonstrated that natural foci of zoonotic cutaneous leishmaniasis are associated with specific landscape complexes featuring characteristic biotopes that support stable rodent populations and provide favorable conditions for sandfly breeding. It was determined that the most effective principle for isolating a focus is to simultaneously target all links in the epidemic process: the deliberate reduction of reservoir host populations within a limited area, the elimination of sandflies at their breeding and resting sites, and the protection of the population from vector bites. The study showed that blanket treatment of vast areas is largely ineffective, whereas the localized isolation of specific foci, followed by epidemiological monitoring, enables the sustained cessation of pathogen circulation. Health education and the timely detection of infected individuals are of great importance. Thus, the containment of natural foci of zoonotic cutaneous leishmaniasis must be based on the landscape-epizootiological zoning of the territory and a comprehensive approach targeting vector and reservoir host populations, taking into account the specific ecological conditions of the focus.