Modeling of leptospirosis outbreaks in relation to hydroclimatic variables in the northeast of Argentina

GÓMEZ, ANDREA; MÜLLER, GABRIELA; LÓPEZ, MARÍA SOLEDAD; SIONE, WALTER F.; GIOVANINI, LEONARDO

Congreso; 2021 MIDAS Network Annual Meeting; 2021

Leptospirosis is a zoonosis found worldwide and it is a major public health issue in many rural and urban surroundings in temperate and tropical climates. Its transmission is conditioned by climatic variables such precipitation, temperature, hydrometric level among others. In northeastern Argentina leptospirosis outbreaks occur mainly in coincidence with periods of abundant precipitation and high hydrometric level that cause portions of land to be flooded for relatively prolonged periods of time, increasing contact between contaminated water and vulnerable populations. In this work, a Susceptible-Infectious-Recovered Epidemiological Model (SIR) is proposed, which incorporates hydroclimatic variables for the three most populated cities in the area (Santa Fe, Paraná and Rosario). The extent of flooded areas, caused by the increase of hydrometric levels, is obtained from a remote sensing method and constitutes a very useful tool to analyze its impact at regional scales. The monthly distribution of precipitation of each year is modelled with a Gamma probability distribution function and incorporated into the SIR model. Results are contrasted against registered leptospirosis cases data during the 2009 – 2018 period in the three cities. For the 2010 outbreak, which was the worst registered one, results obtained by solving the proposed SIR model are in good agreement with the actual data, capturing the dynamics of the leptospirosis outbreak wave. However, the model does not perform very well when isolated cases appear outside the outbreak periods, probably due to non- climatic factors not explicitly considered in the present version of the model. Nevertheless, the dynamic modeling of infectious diseases considering hydroclimatic variables constitutes a climatic service for the public health system, not yet available in Argentina.