Using a One Health approach to asses overall leptospirosis risk in riverside communities of the Parana river in Santa Fe, Argentina

Leptospirosis is a zoonotic disease of global distribution caused by bacteria of the genus Leptospira, acquired by direct or indirect contact with urine of infected mammalian hosts. We used a One Health approach to investigate... [ view full abstract ]

Leptospirosis is a zoonotic disease of global distribution caused by bacteria of the genus Leptospira, acquired by direct or indirect contact with urine of infected mammalian hosts. We used a One Health approach to investigate leptospirosis in an endemic area of Argentina: the floodplains of the Parana river. Our goal was to obtain an integrated measure of overall risk by involving multiple sectors and disciplines to study aspects of animal, human and environmental health that may influence risk. We selected 3 riverside human settlements near the city of Santa Fe to assess the presence of leptospires in environmental water, prevalence of infections in small mammals, and knowledge, attitudes and practices (KAPs) of humans. In each community, we established 3 study sites at varying distances from the community core. Between 2014 and 2015 we conducted 3 trapping sessions for small mammals. A kidney sample was collected from each individual and used in real-time qPCR of the LipL32 gene to determine infection with pathogenic Leptospira. We collected 10 water samples from each community and cultured them to detect presence of lepstospires. Positive samples were analyzed using 16S primers and PCR products sequenced to identify species. Finally, we conducted a household questionnaire assessing people's KAPs during a major river flood. Of the 119 rodents (Sigmodontinae, Muridae and Caviidae) and 2 mouse opossums (Didelphidae) analyzed, only one individual of Scapteromys aquaticus from a core site tested positive. From the same site, we obtained an isolate from water, identified as L. meyeri, a saprophytic leptospire. Additionally, in this community, we observed the highest percentage of surveyed people that lack knowledge on how the disease is transmitted (40%). Considering these preliminary results, we conclude that overall leptospirosis risk appears to differ among these riverside communities, warranting further research and outreach efforts in this area.