Pathogenic Leptospira in Commensal Small Mammals from the Extensively Urbanized Coastal Benin

Abstract

Leptospirosis is caused by spirochete bacteria of the genus Leptospira that affect one million and kill 60,000 persons annually in the world, who get infected through environmental mammal-excreted (notably rodent) pathogens. Using qPCR and DNA sequencing approaches, we here examine Leptospira occurrence and diversity in 971 commensal small mammals in urban and peri-urban habitats from south Benin, where socio-environmental conditions are favorable for human contamination. Prevalence reached 12.9% on average, but showed very important variations in both space and time, thus pointing toward a role of local processes in the maintenance and circulation of rodent-borne leptospires in the area. Prevalence peaks may occur during or one month after moderate (100–200 mm) monthly rainfall, suggesting that rodent-borne leptospires may be more prevalent when standing waters are present, but not at their highest levels (i.e., floods). However, this pattern will have to be confirmed through proper diachronic analysis. Finally, an incomplete but significant host-specificity was observed, with L. kirschneri retrieved only in African shrews, and the invasive Rattus norvegicus and the native Mastomys natalensis preferentially infected by L. interrogans and L. borgpeterseni, respectively. Our study highlights the urgent need for investigations on human leptospirosis in the extensively urbanized Abidjan–Lagos corridor.