Spatio-temporal analysis of leptospirosis incidence and its relationship with hydroclimatic indicators in northeastern Argentina

Leptospirosis is considered the most globally widespread zoonotic illness; it has been classified as an emerging or reemerging infectious disease by the World Health Organization. Leptospirosis is a disease caused by a pathogenic spirochete of the genus Leptospira. The infection occurs by contacting with the urine of animal reservoirs or contaminated environments. Leptospirosis can be controlled by vaccines used mainly in animals, antibiotics given to exposed humans, and flood-affected people moved to a safe place. Northeastern Argentina accounts for the highest annual number of cases and deaths due to leptospirosis of the country. This interdisciplinary study aims to analyze the spatial and temporal distribution of leptospirosis, and assesses the hydroclimatic factors that give rise to the outbreaks in northeastern Argentina. The main goal is to detect the hydroclimatic indicators that can influence leptospirosis outbreaks occurrence in the northeastern Argentina. We perform a spatio-temporal analysis of the leptospirosis in the provinces of Santa Fe and Entre Ríos to distinguish the regions, years and seasons with the highest incidence of this disease. This study analyzes confirmed cases of leptospirosis between 2009 and 2018 years. Hydroclimatic indicators (monthly total precipitation, monthly river hydrometric level and Oceanic Niño Index) associated with outbreaks of leptospirosis vary in different spatial scales (provincial, departmental and cities). In the last outbreak of leptospirosis in 2015-2016 the number of cases was lower than expected. This could have been a consequence of increased prophylaxis in that flood event. Therefore, this is a variable that should be incorporated in future studies.