Co-radiation of Leptospira and Tenrecidae (Afrotheria) on Madagascar

Abstract

Leptospirosis is one of the most prevalent bacterial zoonoses in the world. The disease is caused by pathogenic Leptospira that are maintained in the kidney lumen of infected animals, mostly mammals, acting as reservoirs and contaminating the environment via infected urine. The investigation of leptospirosis through a One Health framework has been stimulated by notable genetic diversity of pathogenic Leptospira together with a high infection prevalence in certain animal reservoirs. Extensive sampling and associated microbiological and molecular studies of Madagascar's native mammal fauna have revealed a diversity of pathogenic Leptospira with high levels of host-specificity. Native rodents, tenrecids, and bats shelter a number of distinct lineages and species of Leptospira, some of which have also been detected in acute human cases. Specifically, L. mayottensis, first discovered in humans on Mayotte, an island neighboring Madagascar, was subsequently identified in a few species of Malagasy tenrecids, an endemic family. Distinct L. mayottensis lineages were identified in shrew tenrecs (Microgale cowani and Nesogale dobsoni) on Madagascar, and later in spiny tenrecs (Tenrec ecaudatus) on Mayotte. These findings suggest that L. mayottensis (i) has experienced co-evolutionary processes during the radiation of tenrecids on Madagascar, and (ii) has recently emerged in human populations on Mayotte following the introduction of T. ecaudatus from Madagascar. Hitherto, L. mayottensis has not been detected in spiny tenrecs on Madagascar. In the present study, we broaden the investigation of Malagasy tenrecids and describe the presence of L. mayottensis in Malagasy populations of T. ecaudatus, as well as in M. thomasi. These results confirm the hypothesis that L. mayottensis was introduced to Mayotte, presumably via T. ecaudatus, and provide additional data on the co-evolution of Leptospira and Tenrecidae.