Abstract
Leptospirosis is a re-emerging zoonotic infectious disease caused by pathogenic bacteria of the genus Leptospira. Regional differences in the disease manifestation and the role of ecological factors, specifically in regions with a subarctic and arctic climate, remain poorly understood. We here explored environmental and socio-economic features associated with leptospirosis cases in livestock animals in the Russian Arctic during 2000–2019. Spatial analysis suggested that the locations of the majority of 808 cases were in “boreal” or “polar” climate regions, with “cropland,” “forest,” “shrubland,” or “settlements” land-cover type, with a predominance of “Polar Moist Cropland on Plain” ecosystem. The cases demonstrated seasonality, with peaks in March, June, and August, corresponding to the livestock pasturing practices. We applied the Forest-based Classification and Regression algorithm to explore the relationships between the cumulative leptospirosis incidence per unit area by municipal districts (G-rate) and a number of socio-economic, landscape, and climatic factors. The model demonstrated satisfactory performance in explaining the observed disease distribution (R2 = 0.82, p < 0.01), with human population density, livestock units density, the proportion of crop area, and budgetary investments into agriculture per unit area being the most influential socio-economic variables. Climatic factors demonstrated a significantly weaker influence, with nearly similar contributions of mean yearly precipitation and air temperature and number of days with above-zero temperatures. Using a projected climate by 2100 according to the RCP8.5 scenario, we predict a climate-related rise of expected disease incidence across most of the study area, with an up to 4.4-fold increase in the G-rate. These results demonstrated the predominant influence of the population and agricultural production factors on the observed increase in leptospirosis cases in livestock animals in the Russian Arctic. These findings may contribute to improvement in the regional system of anti-leptospirosis measures and may be used for further studies of livestock leptospirosis epidemiology at a finer scale.
Highlights
Animal leptospirosis is a re-emerging focal infectious disease that is common in humans and animals globally [1,2,3,4,5]
We studied the manifestation of leptospirosis in livestock animals in the regions located in the Arctic zone of the Russian Federation
The results clearly demonstrated that socio-economic factors were of the greatest importance for explaining the observed distribution of leptospirosis cases, while the role of climatic and landscape factors was less significant
Summary
Animal leptospirosis is a re-emerging focal infectious disease (zoonosis) that is common in humans and animals globally [1,2,3,4,5]. According to some studies [18,19,20], climatic factors rank first among the common causes of endemicity and persistence of leptospirosis in tropical and subtropical countries [5, 21, 22]. Regions and countries with high endemicity are characterized by hot humid weather, and tropical and subtropical climates, which contribute to the survival of pathogenic Leptospira in the external environment [23,24,25]. In addition to the tropical climatic zones where environmental conditions are most favorable for survival of pathogenic Leptospira, the disease is quite widespread among livestock in the temperate latitudes of the Eurasian continent [7, 8, 10]. Other factors contributing to the spread of infection among both humans and animals in these temperate zones are socio-economic phenomena, such as urbanization [17, 28], agricultural intensification [17, 29], as well as changes in the economic status of people, including poverty, homelessness, and even the presence of individual communities in poorly or sparsely populated urban areas [30], which may result in poor hygiene and rodent-borne infections [31,32,33]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
