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Mariën J, Sage M, Bangura U, Lamé A, Koropogui M, Rieger T, Soropogui B, Douno M, Magassouba N, Fichet-Calvet E. Rodent control strategies and Lassa virus: some unexpected effects in Guinea, West Africa. Emerg Microbes Infect 2024; 13:2341141. [PMID: 38597241 PMCID: PMC11034454 DOI: 10.1080/22221751.2024.2341141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 04/04/2024] [Indexed: 04/11/2024]
Abstract
The Natal multimammate mouse (Mastomys natalensis) is the host of Lassa mammarenavirus, causing Lassa haemorrhagic fever in West Africa. As there is currently no operational vaccine and therapeutic drugs are limited, we explored rodent control as an alternative to prevent Lassa virus spillover in Upper Guinea, where the disease is highly endemic in rural areas. In a seven-year experiment, we distributed rodenticides for 10-30 days once a year and, in the last year, added intensive snap trapping for three months in all the houses of one village. We also captured rodents both before and after the intervention period to assess their effectiveness by examining alterations in trapping success and infection rates (Lassa virus RNA and IgG antibodies). We found that both interventions reduced the rodent population by 74-92% but swiftly rebounded to pre-treatment levels, even already six months after the last snap-trapping control. Furthermore, while we observed that chemical control modestly decreased Lassa virus infection rates annually (a reduction of 5% in seroprevalence per year), the intensive trapping unexpectedly led to a significantly higher infection rate (from a seroprevalence of 28% before to 67% after snap trapping control). After seven years, we conclude that annual chemical control, alone or with intensive trapping, is ineffective and sometimes counterproductive in preventing Lassa virus spillover in rural villages. These unexpected findings may result from density-dependent breeding compensation following culling and the survival of a small percentage of chronically infected rodents that may spread the virus to a new susceptible generation of mice.
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Affiliation(s)
- Joachim Mariën
- Evolutionary Ecology group, Department of Biology University of Antwerp, Antwerp, Belgium
- Virus Ecology unit, Department of Biomedical sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Mickaël Sage
- Faune INNOV’ R&D – Wildlife INNOVATION, Besançon, France
| | - Umaru Bangura
- Implementation Research, Zoonoses Control group, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Alicia Lamé
- Faune INNOV’ R&D – Wildlife INNOVATION, Besançon, France
| | - Michel Koropogui
- Projet des fièvres Hémorragiques en Guinée, Laboratoire de Virologie, Conakry, Guinea
| | - Toni Rieger
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Barré Soropogui
- Projet des fièvres Hémorragiques en Guinée, Laboratoire de Virologie, Conakry, Guinea
| | - Moussa Douno
- Projet des fièvres Hémorragiques en Guinée, Laboratoire de Virologie, Conakry, Guinea
| | - N’Faly Magassouba
- Projet des fièvres Hémorragiques en Guinée, Laboratoire de Virologie, Conakry, Guinea
| | - Elisabeth Fichet-Calvet
- Implementation Research, Zoonoses Control group, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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