Small mammal diversity and dynamics within Nigeria, with emphasis on reservoirs of the lassa virus

Abstract

Nigeria has a rich small mammal community, with several species implicated as carriers of zoonotic microbes such as the Lassa virus (LASV). We sought to elucidate the diversity and distribution of these animals (including known LASV reservoirs) geographically, habitat-wise and seasonally. Our DNA-assisted survey detected at least 19 small mammal species amongst 790 specimens. Diversity indices were similar between ecological zones and also between endemic and non-endemic areas for Lassa fever. Mastomys natalensis, the most renowned LASV host, was present in eight out of nine localities sampled. We also described the spatial occurrence of other known LASV hosts such as M. erythroleucus and Hylomyscus pamfi, including carriers of LASV-like arenaviruses such as Mus (Nannomys) spp. The most numerous rodents (Mastomys natalensis, M. erythroleucus, and Praomys daltoni) were captured mainly inside human dwellings. Reproductive activity occurred throughout the year, but led to population peaks for M. natalensis in the dry season and for M. erythroleucus and P. daltoni in the rainy season. Extensive geographic distribution of LASV rodent reservoirs, with population peaks in different seasons, shows that the risk of rodent-to-human transmission of LASV is greater than currently realized.

Keywords:

• ecological zone
• geographic distribution
• Guinea savanna
• habitat
• Lassa fever
• montane forest
• rainforest
• rodent reservoir
• seasonal fluctuation

Acknowledgements

This study was funded by the European Foundation Initiative for African Research into Neglected Tropical Diseases (EFINTD, grant 1/85/022) and the German Research Foundation (DFG, grants GU 883/4-1 & FI 1781/1-1). We are grateful to all our assistants in the field. We also thank the inhabitants and chiefs in the villages we sampled for their warm welcome and support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

Supplemental data for this article can be accessed here: https://doi.org/10.1080/14772000.2017.1358220.

Additional information

Funding

This work was supported by the Deutsche Forschungsgemeinschaft [grant number FI 1781/1-1,GU 883/4-1]; European Foundation Initiative for African Research into Neglected Tropical Diseases (EFINTD) [grant number 1/85/022].