Factors determining the natural foci of leptospirosis in the natural and climatic conditions of the Khabarovsk Territory

Leptospirosis is a non-transmissible natural focal disease with a wide range of reservoir hosts of pathogenic Leptospira and susceptible animal species. Leptospira are chemoorganotrophic, strictly aerobic microorganisms and the optimal pH of the environment for cultivating Leptospira is 7,0–7,6. The purpose of the study is to study the features of the natural and climatic conditions of the Khabarovsk Territory, which contribute to the preservation of Leptospira in the environment and their circulation in mammals. Natural and climatic predisposing factors include: a dense river network, monsoon climate, floods and floods, features of the geomorphological structure of the Amur valley, mountainous terrain, the presence of frozen rocks in the north and loamy soils in the south, soil saturation with water, the presence of marshy areas. Environmental factors contributing to the circulation of leptospira include the nature of the vegetation – in the wide floodplains of the Amur River, sedge-reed meadows are common, which are characterized by natural focality of leptospirosis. The region is home to a large number of semi-aquatic rodents – reservoir hosts of Leptospira. During floods and freshes, rodents migrate from flooded areas, expanding their habitat, thereby contributing to the spread of pathogens of natural focal infections beyond the boundaries of their habitat into areas of temporary removal of the pathogen and permanently safe ones, most often these are populated areas (anthropologic foci of leptospirosis). Among the socio-economic factors contributing to the circulation of Leptospira, it should be noted the location of the main agricultural regions (Khabarovsk, Ulchsky, Nanaisky, Lazo, Komsomolsky, Vyazemsky, Bikinsky and Anursky) in the floodplains and lower reaches of rivers. During periods of seasonal rains and high waters, leptospirosis-carrying rodents migrate to these areas from natural foci of leptospirosis, complicating the epidemiological and epizootological situation.

leptospirosis, soil, water, climate, Khabarovsk Territory