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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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Madueme PGU, Chirove F. A systematic review of mathematical models of Lassa fever. Math Biosci 2024; 374:109227. [PMID: 38844262 DOI: 10.1016/j.mbs.2024.109227] [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: 11/28/2023] [Revised: 02/21/2024] [Accepted: 05/31/2024] [Indexed: 06/13/2024]
Abstract
This systematic review, conducted following the PRISMA guidelines, scrutinizes mathematical models employed in the study of Lassa fever. The analysis revealed the inherent heterogeneity in both models and data, posing significant challenges to parameter estimation. While health and behavioral interventions exhibit promise in mitigating the disease's spread, their efficacy is contingent upon contextual factors. Identified through this review are critical gaps, limitations, and avenues for future research, necessitating increased harmonization and standardization in modeling approaches. The considerations of seasonal and spatial variations emerge as crucial elements demanding targeted investigation. The perpetual threat of emerging diseases, coupled with the enduring public health impact of Lassa fever, underscores the imperative for sustained research endeavors and investments in mathematical modeling. The conclusion underscored that while mathematical modeling remains an invaluable tool in the combat against Lassa fever, its optimal utilization mandates multidisciplinary collaboration, refined data collection methodologies, and an enriched understanding of the intricate disease dynamics. This comprehensive approach is essential for effectively reducing the burden of Lassa fever and safeguarding the health of vulnerable populations.
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Affiliation(s)
- Praise-God Uchechukwu Madueme
- Department of Mathematics and Applied Mathematics, University of Johannesburg, Auckland Park, 2006, Johannesburg, South Africa
| | - Faraimunashe Chirove
- Department of Mathematics and Applied Mathematics, University of Johannesburg, Auckland Park, 2006, Johannesburg, South Africa.
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Moore KA, Ostrowsky JT, Mehr AJ, Johnson RA, Ulrich AK, Moua NM, Fay PC, Hart PJ, Golding JP, Benassi V, Preziosi MP, Adetifa IM, Akpede GO, Ampofo WK, Asogun DA, Barrett ADT, Bausch DG, de Coster I, Emperador DM, Feldmann H, Fichet-Calvet E, Formenty PBH, Garry RF, Grant DS, Günther S, Gupta SB, Jaspard M, Mazzola LT, Okogbenin SA, Roth C, Schmaljohn CS, Osterholm MT. Lassa fever research priorities: towards effective medical countermeasures by the end of the decade. THE LANCET. INFECTIOUS DISEASES 2024:S1473-3099(24)00229-9. [PMID: 38964363 DOI: 10.1016/s1473-3099(24)00229-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/01/2024] [Accepted: 04/04/2024] [Indexed: 07/06/2024]
Abstract
In 2016, WHO designated Lassa fever a priority disease for epidemic preparedness as part of the WHO Blueprint for Action to Prevent Epidemics. One aspect of preparedness is to promote development of effective medical countermeasures (ie, diagnostics, therapeutics, and vaccines) against Lassa fever. Diagnostic testing for Lassa fever has important limitations and key advancements are needed to ensure rapid and accurate diagnosis. Additionally, the only treatment available for Lassa fever is ribavirin, but controversy exists regarding its effectiveness. Finally, no licensed vaccines are available for the prevention and control of Lassa fever. Ongoing epidemiological and behavioural studies are also crucial in providing actionable information for medical countermeasure development, use, and effectiveness in preventing and treating Lassa fever. This Personal View provides current research priorities for development of Lassa fever medical countermeasures based on literature published primarily in the last 5 years and consensus opinion of 20 subject matter experts with broad experience in public health or the development of diagnostics, therapeutics, and vaccines for Lassa fever. These priorities provide an important framework to ensure that Lassa fever medical countermeasures are developed and readily available for use in endemic and at-risk areas by the end of the decade.
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Affiliation(s)
- Kristine A Moore
- Center for Infectious Disease Research and Policy, University of Minnesota, Minneapolis, MN, USA.
| | - Julia T Ostrowsky
- Center for Infectious Disease Research and Policy, University of Minnesota, Minneapolis, MN, USA
| | - Angela J Mehr
- Center for Infectious Disease Research and Policy, University of Minnesota, Minneapolis, MN, USA
| | - Rebecca A Johnson
- Center for Infectious Disease Research and Policy, University of Minnesota, Minneapolis, MN, USA
| | - Angela K Ulrich
- Center for Infectious Disease Research and Policy, University of Minnesota, Minneapolis, MN, USA
| | - Nicolina M Moua
- Center for Infectious Disease Research and Policy, University of Minnesota, Minneapolis, MN, USA
| | - Petra C Fay
- Infectious Disease Strategic Programme, Wellcome Trust, London, UK
| | - Peter J Hart
- Infectious Disease Strategic Programme, Wellcome Trust, London, UK
| | | | | | | | | | - George O Akpede
- Ambrose Alli University, Ekpoma, Nigeria; Institute of Viral and Emergent Pathogens Control and Research (formerly, Institute of Lassa Fever Research and Control), Irrua Specialist Teaching Hospital, Irrua, Nigeria
| | | | | | - Alan D T Barrett
- Sealy Institute for Vaccine Sciences and Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Daniel G Bausch
- FIND, Geneva, Switzerland; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Ilse de Coster
- Centre for the Evaluation of Vaccination, University of Antwerp, Antwerp, Belgium
| | | | - Heinz Feldmann
- Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | | | | | - Robert F Garry
- Tulane University, New Orleans, LA, USA; Zalgen Labs, Frederick, MD, USA; Global Viral Network, Baltimore, MD, USA
| | - Donald S Grant
- Kenema Government Hospital, Ministry of Health and Sanitation, Freetown, Sierra Leone; College of Medicine and Allied Health Sciences, University of Sierra Leone, Freetown, Sierra Leone
| | - Stephan Günther
- Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Swati B Gupta
- lnternational AIDS Vaccine Initiative, New York, NY, USA
| | - Marie Jaspard
- The Alliance for International Medical Action, Dakar, Senegal; Saint-Antoine Hospital, Infectious Disease Department, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM Unit 1136 Institut Pierre Louis D'Epidémiologie et de Sante Publique, Paris, France
| | | | | | - Cathy Roth
- UK Foreign, Commonwealth and Development Office, London, UK
| | - Connie S Schmaljohn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, Frederick, Maryland, USA
| | - Michael T Osterholm
- Center for Infectious Disease Research and Policy, University of Minnesota, Minneapolis, MN, USA
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Smith DRM, Turner J, Fahr P, Attfield LA, Bessell PR, Donnelly CA, Gibb R, Jones KE, Redding DW, Asogun D, Ayodeji OO, Azuogu BN, Fischer WA, Jan K, Olayinka AT, Wohl DA, Torkelson AA, Dinkel KA, Nixon EJ, Pouwels KB, Hollingsworth TD. Health and economic impacts of Lassa vaccination campaigns in West Africa. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.02.26.24303394. [PMID: 38978680 PMCID: PMC11230338 DOI: 10.1101/2024.02.26.24303394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Lassa fever is a zoonotic disease identified by the World Health Organization (WHO) as having pandemic potential. This study estimates the health-economic burden of Lassa fever throughout West Africa and projects impacts of a series of vaccination campaigns. We also model the emergence of "Lassa-X" - a hypothetical pandemic Lassa virus variant - and project impacts of achieving 100 Days Mission vaccination targets. Our model predicted 2.7M (95% uncertainty interval: 2.1M-3.4M) Lassa virus infections annually, resulting over ten years in 2.0M (793.8K-3.9M) disability-adjusted life years (DALYs). The most effective vaccination strategy was a population-wide preventive campaign primarily targeting WHO-classified "endemic" districts. Under conservative vaccine efficacy assumptions, this campaign averted $20.1M ($8.2M-$39.0M) in lost DALY value and $128.2M ($67.2M-$231.9M) in societal costs (International dollars 2021). Reactive vaccination in response to local outbreaks averted just one-tenth the health-economic burden of preventive campaigns. In the event of Lassa-X emerging, spreading throughout West Africa and causing approximately 1.2M DALYs within two years, 100 Days Mission vaccination averted 22% of DALYs given a vaccine 70% effective against disease, and 74% of DALYs given a vaccine 70% effective against both infection and disease. These findings suggest how vaccination could alleviate Lassa fever's burden and assist in pandemic preparedness.
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Kaboré L, Pecenka C, Hausdorff WP. Lassa fever vaccine use cases and demand: Perspectives from select West African experts. Vaccine 2024; 42:1873-1877. [PMID: 38369392 DOI: 10.1016/j.vaccine.2024.02.044] [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: 11/17/2023] [Revised: 02/05/2024] [Accepted: 02/14/2024] [Indexed: 02/20/2024]
Abstract
Lassa fever (LF) is a zoonotic viral hemorrhagic disease endemic to several West African countries. Approximately 300-500,000 cases occur annually across all ages with 10-20% case fatality rates. A LF vaccine is a recognized public health priority, with several candidates entering clinical trials. However, the perspectives of regional experts regarding critical vaccine properties, ideal delivery methods, and priority target populations remain unclear. Using a mixed methods approach with a standardized questionnaire, we individually interviewed 8 West African stakeholders, each with extensive knowledge and experience of LF. They strongly favored the use of a mass, proactive campaign strategy to immunize a wide age range of people in high-risk areas, including pregnant women and health care workers. We estimated that these and other plausible delivery scenarios could result in an initial demand of anywhere from 1 to 100 million doses, with most demand coming from Nigeria. These findings may help inform LF vaccine development and deployment efforts.
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Affiliation(s)
- Lassané Kaboré
- PATH, Fann Résidence Rue Saint John Perse x F, Dakar, Senegal
| | - Clint Pecenka
- PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA 98121, USA
| | - William P Hausdorff
- PATH, 455 Massachusetts Ave NW, Washington DC 20001, USA; Université Libre de Bruxelles, Brussels, Belgium.
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