Biogeography of Leptospira in wild animal communities inhabiting the insular ecosystem of the western Indian Ocean islands and neighboring Africa

Abstract

Understanding the processes driving parasite assemblages is particularly important in the context of zoonotic infectious diseases. Leptospirosis is a widespread zoonotic bacterial infection caused by pathogenic species of the genus Leptospira. Despite a wide range of animal hosts, information is still lacking on the factors shaping Leptospira diversity in wild animal communities, especially in regions, such as tropical insular ecosystems, with high host species richness and complex biogeographical patterns. Using a large dataset (34 mammal species) and a multilocus approach at a regional scale, we analyzed the role of both host species diversity and geography in Leptospira genetic diversity in terrestrial small mammals (rodents, tenrecs, and shrews) and bats from 10 different islands/countries in the western Indian Ocean (WIO) and neighboring Africa. At least four Leptospira spp. (L. interrogans, L. borgpetersenii, L. kirschneri, and L. mayottensis) and several yet-unidentified genetic clades contributed to a remarkable regional Leptospira diversity, which was generally related to the local occurrence of the host species rather than the geography. In addition, the genetic structure patterns varied between Leptospira spp., suggesting different evolutionary histories in the region, which might reflect both in situ diversification of native mammals (for L. borgpetersenii) and the more recent introduction of non-native host species (for L. interrogans). Our data also suggested that host shifts occurred between bats and rodents, but further investigations are needed to determine how host ecology may influence these events.

Synchronized shift of oral, faecal and urinary microbiotas in bats and natural infection dynamics during seasonal reproduction

“…For M. natalensis , among the bats sampled at two ( n = 85) or three ( n = 30) body habitats, 45% were infected by two infectious agents and 17% were infected by the three infectious agents. Leptospira -positive urine samples in M. natalensis clustered in two genetic groups ( figure 2 a ), one associated with L. borgpetersenii samples previously identified in M. natalensis in South Africa [ 26 ] and the other closely related to L. interrogans and L. kirschneri . High Leptospira shedding prevalence was observed across the reproductive season, varying between 71% (±18%) and 87% (±10%).…”

Genetic diversity of pathogenic leptospires from wild, domestic and captive host species in Portugal

“…Previous studies noticed that MLST approaches may contribute to unravel potential associations between specific Leptospira STs and their hosts and geographic regions of origin (Boonsilp et al, ; Dietrich et al, , ). For example, Dietrich et al () found a distinct clustering of Leptospira isolates according to their different small mammal host species in Madagascar.…”

Complete Genome Sequences of Three Leptospira mayottensis Strains from Tenrecs That Are Endemic in the Malagasy Region

“…This zoonosis is estimated to cause more than one million human cases and 58,900 deaths each year ( 1 ). Disease incidence is highest on tropical islands, notably in the southwestern Indian Ocean, where investigations carried out under a One Health framework have revealed distinct transmission chains in the different islands ( 2 – 5 ), including the occurrence of Leptospira mayottensis , a pathogenic Leptospira species recently recognized as new to science ( 6 ). Representatives of L. mayottensis (formerly known as Leptospira borgpetersenii group B) were originally isolated from human acute cases ( 7 ) and later identified in tenrecs ( 2 , 5 , 8 ), a diversified family of mammals endemic to Madagascar ( 9 , 10 ).…”

“…Three L. mayottensis strains were isolated in the field from two tenrec species, namely, Tenrec ecaudatus on Mayotte (MDI222 and MDI272) ( 2 ) and Microgale dobsoni on Madagascar (VS2413) ( 5 ). Frozen isolates were thawed in liquid Ellinghausen-McCullough-Johnson-Harris (EMJH) medium containing albumin fatty acid supplements (AFAS) ( 3 ), and they were further subcultured in EMJH supplemented with AFAS, 1% fetal calf serum, and 8% rabbit serum.…”