U of I Researcher Evan Eskew

Publishes in Nature Communications

May 16, 2024

University of Idaho researcher Evan Eskew (Idaho Initiative for Computational One Health) recently published in Nature Communications. Fellow U of I researchers Scott Nuismer (Biological Sciences) and Andrew Basinski (formerly with the Institute of Interdisciplinary Data Sciences) co-authored "Reservoir displacement by an invasive rodent reduces Lassa virus zoonotic spillover risk". This publication developed from a series of research projects on Lassa virus at University of Idaho involving Scott Nuismer and numerous other experts, including Elisabeth Fichet-Calvet at the Bernhard Nocht Institute for Tropical Medicine and researchers with the One Health Institute at the University of California, Davis. This work was supported by the National Institutes of Health through grant number R01GM122079 (S.L.N.), the National Science Foundation’s Division of Environmental Biology through grant number 2028162 (S.L.N.), the Defense Advanced Research Projects Agency through grant number D18AC00028 (B.H.B., S.L.N.), and the European Union through INCO-DEV grant number ICA4-CT2002-10050 (E.F.-C.).

Lassa fever is a deadly, rodent-borne hemorrhagic disease which is a major health threat in West Africa. Prior research from Scott Nuismer suggests that nearly one million individuals are infected annually. Despite these infection numbers, Lassa virus has been largely neglected by researchers. Like Ebola, H1N1, SARS and COVID-19, Lassa fever outbreaks are the result of zoonotic spillover infections. In the case of Lassa, these spillover infections come from a rodent reservoir host, the Natal multimammate mouse (Mastomys natalensis). Understanding local rodent ecology is the key to reducing the risk of Lassa virus spillover infections and improving public health.

This publication examines the relationship between the Lassa virus reservoir host M. natalensis and a notorious invasive species, the black rat (Rattus rattus). R. rattus was introduced into port cities of the region as early as the 15th century. Today the black rat is continuing to spread to inland West Africa, impacting local rodent populations. Data suggests that R. rattus outcompetes M. natalensis, negatively affecting their population numbers. Further, the movement of R. rattus to inland West Africa appears to be having the unexpected benefit of reducing Lassa virus spillover to humans by reducing M. natalensis densities. While the spread of an invasive species typically has negative ecosystem effects, in this case the invasive black rat is having some positive effect by reducing the risk of human Lassa virus infections.

This counterintuitive result encourages researchers to study Lassa virus, and disease systems generally, with a broad view of the ecological system of interest. It is not only important to study the primary host of a virus, but also the other ecological community members that might influence the occurrence and abundance of the host species.

Evan A. Eskew, Brian H. Bird, Bruno M. Ghersi, James Bangura, Andrew J. Basinski, Emmanuel Amara, Mohamed A. Bah, Marilyn C. Kanu, Osman T. Kanu, Edwin G. Lavalie,, Victor Lungay, Willie Robert, Mohamed A. Vandi, Elisabeth Fichet-Calvet, and Scott L. Nuismer. Reservoir displacement by an invasive rodent reduces Lassa virus zoonotic spillover risk. Nature Communications 15, 3589 (2024). See the full publication here.

by Michelle Reagan Scientific Communications and Design Specialist