Land use gradients drive spatial variation in Lassa fever host communities in the Eastern Province of Sierra Leone.

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Authors

David Simons, Rory Gibb, Umaru Bangura, Dianah Sondufu, Joyce Lamin, James Koninga, Momoh Jimmy, Mike Dawson, Joseph Lahai, Rashid Ansumana, Elisabeth Fichet-Calvet, Deborah Watson-Jones, Richard Kock, Kate E Jones

Abstract


  1. The natal multimammate mouse (Mastomys natalensis) is the primary reservoir host of Lassa mammarenavirus (LASV), a zoonotic pathogen causing Lassa fever that is endemic to West Africa. The occurrence and abundance of this species is regulated by the human environment and biotic interactions with other small-mammal species, but these ecological drivers remain poorly understood in the regions where Lassa fever outbreaks are observed.

  2. We developed a Bayesian multi-species occupancy model incorporating incomplete detection to assess habitat use from data obtained as part of a multi-year small-mammal trapping study (43,226 trap nights across four village sites in Sierra Leone, 2020-2023). We investigated the effects of land use gradients and small-mammal community dynamics on the spatial distribution of M. natalensis.

  3. Mastomys natalensis occupancy increased along a gradient from forest to agriculture to village habitats but was reduced in peri-urban settings compared to rural settings. Invasive rodent species influenced this pattern, with Mus musculus presence associated with reduced M. natalensis occupancy in peri-urban settings. We did not observe a similar effect when considering the co-occurrence of invasive Rattus rattus with M. natalensis in rural settings.

  4. These findings suggest that land use and species interactions drive spatial heterogeneity in M. natalensis populations, potentially explaining reduced Lassa fever incidence in urban areas. The results highlight the importance of considering community dynamics when predicting the risk of outbreaks of endemic zoonoses and the need to widen the context of studies of LASV transmission beyond the primary reservoir host species.

  5. To better assess public health risk and improve allocation of limited resources, we recommend more precise characterisation of small-mammal communities in LASV endemic regions, particularly in areas undergoing rapid land use change which may alter community level small-mammal biodiversity.

DOI

https://doi.org/10.32942/X2N33P

Subjects

Ecology and Evolutionary Biology, Epidemiology, Life Sciences, Virus Diseases

Keywords

Rodent associated zoonoses, disease ecology, Viral zoonoses

Dates

Published: 2025-02-03 10:40

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License

CC BY Attribution 4.0 International

Additional Metadata

Language:
English

Conflict of interest statement:
All authors report no financial conflicts of interest.

Data and Code Availability Statement:
Individual level rodent data are available on PHAROS (https://pharos.viralemergence.org/projects/?prj=prjyg91YQvrdk) code required to reproduce the analyses are available on GitHub (https://github.com/DidDrog11/land-use-lassa-hosts)