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Bangura U, Davis C, Lamin J, Bangura J, Soropogui B, Davison AJ, Nichols J, Vucak M, Dawson M, Ansumana R, Sondufu D, Cadar D, Rieger T, Thomson E, Sahr F, Magassouba N, Ghersi B, Bird BH, Fichet-Calvet E. Spatio-temporal spread of Lassa virus and a new rodent host in the Mano River Union area, West Africa. Emerg Microbes Infect 2024; 13:2290834. [PMID: 38047354 PMCID: PMC10919312 DOI: 10.1080/22221751.2023.2290834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/29/2023] [Indexed: 12/05/2023]
Abstract
The spread of Lassa virus (LASV) in Guinea, Liberia and Sierra Leone, which together are named the Mano River Union (MRU) area, was examined phylogeographically. To provide a reliable evolutionary scenario, new rodent-derived, whole LASV sequences were included. These were generated by metatranscriptomic next-generation sequencing from rodents sampled between 2003 and 2020 in 21 localities of Guinea and Sierra Leone. An analysis was performed using BEAST to perform continuous phylogeographic inference and EvoLaps v36 to visualize spatio-temporal spread. LASV was identified as expected in its primary host reservoir, the Natal multimammate mouse (Mastomys natalensis), and also in two Guinean multimammate mice (Mastomys erythroleucus) in northern Sierra Leone and two rusty-bellied brush-furred mice (Lophuromys sikapusi) in southern Sierra Leone. This finding is consistent with the latter two species being secondary host reservoirs. The strains in these three species were very closely related in LASV lineage IV. Phylogenetic analysis indicated that the most recent common ancestor of lineage IV existed 316-374 years ago and revealed distinct, well-supported clades from Sierra Leone (Bo, Kabala and Kenema), Guinea (Faranah, Kissidougou-Guekedou and Macenta) and Liberia (Phebe-Ganta). The phylogeographic scenario suggests southern Guinea as the point of origin of LASV in the MRU area, with subsequent spread to towards Mali, Liberia and Sierra Leone at a mean speed of 1.6 to 1.1 km/year.
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Affiliation(s)
- Umaru Bangura
- Bernhard Nocht Institute for Tropical Medicine, WHO Collaborating Centre for Arbovirus and Hemorrhagic Fever Reference and Research, Hamburg, Germany
| | | | - Joyce Lamin
- Mercy Hospital Research Laboratory, Bo, Sierra Leone
| | - James Bangura
- University of Makeni and University of California, Davis One Health Program, Makeni, Sierra Leone
| | - Barré Soropogui
- Laboratoire des Fièvres Hémorragiques en Guinée, Conakry, Guinea
| | | | - Jenna Nichols
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Matej Vucak
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | | | | | | | - Dániel Cadar
- Bernhard Nocht Institute for Tropical Medicine, WHO Collaborating Centre for Arbovirus and Hemorrhagic Fever Reference and Research, Hamburg, Germany
| | - Toni Rieger
- Bernhard Nocht Institute for Tropical Medicine, WHO Collaborating Centre for Arbovirus and Hemorrhagic Fever Reference and Research, Hamburg, Germany
| | - Emma Thomson
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Foday Sahr
- College of Medicine and Allied Health Sciences, University of Sierra Leone, Freetown, Sierra Leone
| | | | - Bruno Ghersi
- One Health Institute, School of Veterinary Medicine, University of California, Davis, Davis, CA, USA
| | - Brian H. Bird
- One Health Institute, School of Veterinary Medicine, University of California, Davis, Davis, CA, USA
| | - Elisabeth Fichet-Calvet
- Bernhard Nocht Institute for Tropical Medicine, WHO Collaborating Centre for Arbovirus and Hemorrhagic Fever Reference and Research, Hamburg, Germany
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2
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Besson ME, Pépin M, Metral PA. Lassa Fever: Critical Review and Prospects for Control. Trop Med Infect Dis 2024; 9:178. [PMID: 39195616 PMCID: PMC11359316 DOI: 10.3390/tropicalmed9080178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2024] [Revised: 08/10/2024] [Accepted: 08/12/2024] [Indexed: 08/29/2024] Open
Abstract
Lassa Fever is a deadly viral haemorrhagic disease, causing annually several hundreds of deaths in West Africa. This zoonotic disease is primarily transmitted to humans by rodents of the genus Mastomys, even though other rodents reportedly carry the Lassa virus, while secondary interhuman transmission accounts for approximately 20% of cases. Although this disease has been endemic in rural zones of Nigeria, Sierra Leone, Liberfia, and Guinea for hundreds of years, it is also characterised by epidemic outbreaks in the dry season, responsible for heavy death tolls. No licensed vaccine or satisfying treatment is currently available. Disease management is hindered by the incomplete knowledge of the epidemiology and distribution of the disease, resulting from an inadequate health and surveillance system. Additional scientific constraints such as the genetic diversity of the virus and the lack of understanding of the mechanisms of immune protection complexify the development of a vaccine. The intricate socio-economic context in the affected regions, and the lack of monetary incentive for drug development, allow the disease to persist in some of West Africa's poorest communities. The increase in the number of reported cases and in the fatality rate, the expansion of the endemic area, as well as the threat Lassa Fever represents internationally should urge the global community to work on the disease control and prevention. The disease control requires collaborative research for medical countermeasures and tailored public health policies. Lassa Fever, created by the interconnection between animals, humans, and ecosystems, and embedded in an intricate social context, should be addressed with a 'One Health' approach. This article provides an overview of Lassa Fever, focusing on Nigeria, and discusses the perspectives for the control of disease.
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Affiliation(s)
- Marianne E. Besson
- Department of Public Health, Royal Veterinary College, London NW1 0TU, UK
| | - Michel Pépin
- Department of Virology and Infectiology, VetAgro Sup Lyon University, 69280 Marcy L’Etoile, France;
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3
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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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4
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John RS, Fatoyinbo HO, Hayman DTS. Modelling Lassa virus dynamics in West African Mastomys natalensis and the impact of human activities. J R Soc Interface 2024; 21:20240106. [PMID: 39045680 PMCID: PMC11267396 DOI: 10.1098/rsif.2024.0106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/25/2024] [Accepted: 06/04/2024] [Indexed: 07/25/2024] Open
Abstract
Lassa fever is a West African rodent-borne viral haemorrhagic fever that kills thousands of people a year, with 100 000 to 300 000 people a year probably infected by Lassa virus (LASV). The main reservoir of LASV is the Natal multimammate mouse, Mastomys natalensis. There is reported asynchrony between peak infection in the rodent population and peak Lassa fever risk among people, probably owing to differing seasonal contact rates. Here, we developed a susceptible-infected-recovered ([Formula: see text])-based model of LASV dynamics in its rodent host, M. natalensis, with a persistently infected class and seasonal birthing to test the impact of changes to seasonal birthing in the future owing to climate and land use change. Our simulations suggest shifting rodent birthing timing and synchrony will alter the peak of viral prevalence, changing risk to people, with viral dynamics mainly stable in adults and varying in the young, but with more infected individuals. We calculate the time-average basic reproductive number, [Formula: see text], for this infectious disease system with periodic changes to population sizes owing to birthing using a time-average method and with a sensitivity analysis show four key parameters: carrying capacity, adult mortality, the transmission parameter among adults and additional disease-induced mortality impact the maintenance of LASV in M. natalensis most, with carrying capacity and adult mortality potentially changeable owing to human activities and interventions.
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Affiliation(s)
- Reju Sam John
- Massey University, Private Bag, 11 222, Palmerston North4442, New Zealand
| | | | - David T. S. Hayman
- Massey University, Private Bag, 11 222, Palmerston North4442, New Zealand
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5
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Eskew EA, Bird BH, Ghersi BM, Bangura J, Basinski AJ, Amara E, Bah MA, Kanu MC, Kanu OT, Lavalie EG, Lungay V, Robert W, Vandi MA, Fichet-Calvet E, Nuismer SL. Reservoir displacement by an invasive rodent reduces Lassa virus zoonotic spillover risk. Nat Commun 2024; 15:3589. [PMID: 38678025 PMCID: PMC11055883 DOI: 10.1038/s41467-024-47991-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 04/17/2024] [Indexed: 04/29/2024] Open
Abstract
The black rat (Rattus rattus) is a globally invasive species that has been widely introduced across Africa. Within its invasive range in West Africa, R. rattus may compete with the native rodent Mastomys natalensis, the primary reservoir host of Lassa virus, a zoonotic pathogen that kills thousands annually. Here, we use rodent trapping data from Sierra Leone and Guinea to show that R. rattus presence reduces M. natalensis density within the human dwellings where Lassa virus exposure is most likely to occur. Further, we integrate infection data from M. natalensis to demonstrate that Lassa virus zoonotic spillover risk is lower at sites with R. rattus. While non-native species can have numerous negative effects on ecosystems, our results suggest that R. rattus invasion has the indirect benefit of decreasing zoonotic spillover of an endemic pathogen, with important implications for invasive species control across West Africa.
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Affiliation(s)
- Evan A Eskew
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, ID, USA.
| | - Brian H Bird
- One Health Institute, School of Veterinary Medicine, University of California - Davis, Davis, CA, USA
| | - Bruno M Ghersi
- One Health Institute, School of Veterinary Medicine, University of California - Davis, Davis, CA, USA
- Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
| | | | - Andrew J Basinski
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, ID, USA
| | | | - Mohamed A Bah
- Ministry of Agriculture and Forestry, Freetown, Sierra Leone
| | | | | | | | | | | | | | | | - Scott L Nuismer
- Department of Biological Sciences, University of Idaho, Moscow, ID, USA.
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6
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Olayemi A, Schmid DW, Fleischer R, Wilhelm K, Heni AC, Mueller-Klein N, Haikukutu L, Fichet-Calvet E, Günther S, Sommer S. MHC-I alleles mediate clearance and antibody response to the zoonotic Lassa virus in Mastomys rodent reservoirs. PLoS Negl Trop Dis 2024; 18:e0011984. [PMID: 38421939 PMCID: PMC10903922 DOI: 10.1371/journal.pntd.0011984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 02/09/2024] [Indexed: 03/02/2024] Open
Abstract
West African Mastomys rodents are the primary reservoir of the zoonotic Lassa virus (LASV). The virus causes haemorrhagic Lassa fever and considerable mortality in humans. To date, the role of Mastomys immunogenetics in resistance to, and persistence of, LASV infections is largely unknown. Here, we investigated the role of Major Histocompatibility Complex class I (MHC-I) on LASV infection status (i.e., active vs. cleared infection, determined via PCR and an immunofluorescence assay on IgG antibodies, respectively) in Mastomys natalensis and M. erythroleucus sampled within southwestern Nigeria. We identified more than 190 and 90 MHC-I alleles by Illumina high throughput-sequencing in M. natalensis and M. erythroleucus, respectively, with different MHC allele compositions and frequencies between LASV endemic and non-endemic sites. In M. natalensis, the MHC allele ManaMHC-I*006 was negatively associated with active infections (PCR-positive) and positively associated with cleared infections (IgG-positive) simultaneously, suggesting efficient immune responses that facilitate LASV clearance in animals carrying this allele. Contrarily, alleles ManaMHC-I*008 and ManaMHC-I*021 in M. natalensis, and MaerMHC-I*008 in M. erythroleucus, were positively associated with active infection, implying susceptibility. Alleles associated with susceptibility shared a glutamic acid at the positively selected codon 57, while ManaMHC-I*006 featured an arginine. There was no link between number of MHC alleles per Mastomys individual and LASV prevalence. Thus, specific alleles, but not MHC diversity per se, seem to mediate antibody responses to viremia. We conclude that co-evolution with LASV likely shaped the MHC-I diversity of the main LASV reservoirs in southwestern Nigeria, and that information on reservoir immunogenetics may hold insights into transmission dynamics and zoonotic spillover risks.
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Affiliation(s)
- Ayodeji Olayemi
- Natural History Museum, Obafemi Awolowo University, Ile Ife, Osun State, Nigeria
| | - Dominik Werner Schmid
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - Ramona Fleischer
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - Kerstin Wilhelm
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | | | - Nadine Mueller-Klein
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - Lavinia Haikukutu
- Department of Wildlife Management, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Elisabeth Fichet-Calvet
- Department of Zoonoses Control, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stephan Günther
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Simone Sommer
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
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7
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Layman NC, Basinski AJ, Zhang B, Eskew EA, Bird BH, Ghersi BM, Bangura J, Fichet-Calvet E, Remien CH, Vandi M, Bah M, Nuismer SL. Predicting the fine-scale spatial distribution of zoonotic reservoirs using computer vision. Ecol Lett 2023; 26:1974-1986. [PMID: 37737493 PMCID: PMC11298155 DOI: 10.1111/ele.14307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/16/2023] [Accepted: 08/22/2023] [Indexed: 09/23/2023]
Abstract
Zoonotic diseases threaten human health worldwide and are often associated with anthropogenic disturbance. Predicting how disturbance influences spillover risk is critical for effective disease intervention but difficult to achieve at fine spatial scales. Here, we develop a method that learns the spatial distribution of a reservoir species from aerial imagery. Our approach uses neural networks to extract features of known or hypothesized importance from images. The spatial distribution of these features is then summarized and linked to spatially explicit reservoir presence/absence data using boosted regression trees. We demonstrate the utility of our method by applying it to the reservoir of Lassa virus, Mastomys natalensis, within the West African nations of Sierra Leone and Guinea. We show that, when trained using reservoir trapping data and publicly available aerial imagery, our framework learns relationships between environmental features and reservoir occurrence and accurately ranks areas according to the likelihood of reservoir presence.
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Affiliation(s)
- Nathan C. Layman
- EcoHealth Alliance, 520 Eighth Avenue, Ste. 1200, New York, NY 10018 and Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, ID 83843
| | - Andrew J. Basinski
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, ID 83843
| | - Boyu Zhang
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, ID 83843
| | - Evan A. Eskew
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, ID 83843
| | - Brian H. Bird
- One Health Institute, School of Veterinary Medicine, University of California - Davis, One Shields Avenue, Davis, CA 95616
| | - Bruno M. Ghersi
- Tufts University, 419 Boston Avenue, Medford, MA 02155 and One Health Institute, School of Veterinary Medicine, University of California - Davis, One Shields Avenue, Davis, CA 95616
| | - James Bangura
- University of Makeni and University of California, Davis One Health Program, Makeni, Sierra Leone
| | - Elisabeth Fichet-Calvet
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strafie 74, 20359 Hamburg, Germany
| | - Christopher H. Remien
- Department of Mathematics and Statistical Science, University of Idaho, Moscow, ID 83843
| | - Mohamed Vandi
- Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Mohamed Bah
- Ministry of Agriculture and Forestry, Freetown, Sierra Leone
| | - Scott L. Nuismer
- Department of Biological Sciences, University of Idaho, Moscow, ID 83843
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McKendrick JQ, Tennant WSD, Tildesley MJ. Modelling seasonality of Lassa fever incidences and vector dynamics in Nigeria. PLoS Negl Trop Dis 2023; 17:e0011543. [PMID: 37956170 PMCID: PMC10681316 DOI: 10.1371/journal.pntd.0011543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/27/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
Lassa fever (Lf) is a viral haemorrhagic disease endemic to West Africa and is caused by the Lassa mammarenavirus. The rodent Mastomys natalensis serves as the primary reservoir and its ecology and behaviour have been linked to the distinct spatial and temporal patterns in the incidence of Lf. Nigeria has experienced an unprecedented epidemic that lasted from January until April of 2018, which has been followed by subsequent epidemics of Lf in the same period every year since. While previous research has modelled the case seasonality within Nigeria, this did not capture the seasonal variation in the reproduction of the zoonotic reservoir and its effect on case numbers. To this end, we introduce an approximate Bayesian computation scheme to fit our model to the case data from 2018-2020 supplied by the NCDC. In this study we used a periodically forced seasonal nonautonomous system of ordinary differential equations as a vector model to demonstrate that the population dynamics of the rodent reservoir may be responsible for the spikes in the number of observed cases in humans. The results show that in December through to March, spillover from the zoonotic reservoir drastically increases and spreads the virus to the people of Nigeria. Therefore to effectively combat Lf, attention and efforts should be concentrated during this period.
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Affiliation(s)
- James Q. McKendrick
- MathSys, Mathematical Institute, Zeeman Building, University of Warwick, Coventry, United Kingdom
| | - Warren S. D. Tennant
- Zeeman Institute: SBIDER, School of Life Sciences and Mathematics Institute, University of Warwick, Coventry, United Kingdom
| | - Michael J. Tildesley
- Zeeman Institute: SBIDER, School of Life Sciences and Mathematics Institute, University of Warwick, Coventry, United Kingdom
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9
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Smither AR, Koninga J, Kanneh FB, Foday M, Boisen ML, Bond NG, Momoh M, Sandi JD, Kanneh L, Alhasan F, Kanneh IM, Yillah MS, Grant DS, Bush DJ, Nelson DKS, Cruz KM, Klitting R, Pauthner M, Andersen KG, Shaffer JG, Cross RW, Schieffelin JS, Garry RF. Novel Tools for Lassa Virus Surveillance in Peri-domestic Rodents. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.03.17.23287380. [PMID: 36993465 PMCID: PMC10055574 DOI: 10.1101/2023.03.17.23287380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Background Lassa fever (LF) is a rodent-borne disease endemic to West Africa. In the absence of licensed therapeutics or vaccines, rodent exclusion from living spaces remains the primary method of preventing LF. Zoonotic surveillance of Lassa virus (LASV), the etiologic agent of LF, can assess the burden of LASV in a region and guide public health measures against LF. Methods In this study, we adapted commercially available LASV human diagnostics to assess the prevalence of LASV in peri-domestic rodents in Eastern Sierra Leone. Small mammal trapping was conducted in Kenema district, Sierra Leone between November 2018-July 2019. LASV antigen was detected using a commercially available LASV NP antigen rapid diagnostic test. LASV IgG antibodies against LASV nucleoprotein (NP) and glycoprotein (GP) were tested by adapting a commercially available semi-quantitative enzyme linked immunosorbent assay (ELISA) for detection of mouse-related and rat-related species IgG. Findings Of the 373 tested specimens, 74 (20%) tested positive for LASV antigen. 40 (11%) specimens tested positive for LASV NP IgG, while an additional 12 (3%) specimens only tested positive for LASV GP IgG. Simultaneous antigen presence and IgG antibody presence was linked in Mastomys sp. specimens (p < 0.01), but not Rattus sp. specimens (p = 1). Despite the link between antigen presence and IgG antibody presence in Mastomys sp., the strength of antigen response did not correlate with the strength of IgG response to either GP IgG or NP IgG. Interpretation The tools developed in this study can aid in the generation of valuable public health data for rapid field assessment of LASV burden during outbreak investigations and general LASV surveillance. Funding Funding for this work was supported by the National Institute of Allergy and Infectious Diseases National Institute of Health, Department of Health and Human Services under the following grants: International Collaboration in Infectious Disease Research on Lassa fever and Ebola - ICIDR - U19 AI115589, Consortium for Viral Systems Biology - CViSB - 5U19AI135995, West African Emerging Infectious Disease Research Center - WARN-ID - U01AI151812, West African Center for Emerging Infectious Diseases: U01AI151801.
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Affiliation(s)
- Allison R. Smither
- Tulane University School of Medicine, Department of Microbiology and Immunology, New Orleans, LA, USA
- University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX, USA
| | - James Koninga
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Franklyn B. Kanneh
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Momoh Foday
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | | | - Nell G. Bond
- Tulane University School of Medicine, Department of Microbiology and Immunology, New Orleans, LA, USA
| | - Mambu Momoh
- Tulane University School of Medicine, Department of Microbiology and Immunology, New Orleans, LA, USA
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - John Demby Sandi
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Lansana Kanneh
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Foday Alhasan
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Ibrahim Mustapha Kanneh
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Mohamed S. Yillah
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Donald S. Grant
- Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
- College of Medicine and Allied Health Sciences, University of Sierra Leone
| | | | | | - Kaitlin M. Cruz
- Tulane University School of Medicine, Department of Pediatrics, Section of Infectious Disease, New Orleans, LA, USA
| | - Raphaëlle Klitting
- The Scripps Research Institute, Department of Microbiology and Immunology, La Jolla, CA, USA
| | - Matthias Pauthner
- The Scripps Research Institute, Department of Microbiology and Immunology, La Jolla, CA, USA
| | - Kristian G. Andersen
- The Scripps Research Institute, Department of Microbiology and Immunology, La Jolla, CA, USA
| | - Jeffrey G. Shaffer
- Tulane University School of Public Health and Tropical Medicine, Department of Biostatistics, New Orleans, LA, USA
| | - Robert W. Cross
- University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX, USA
| | - John S. Schieffelin
- Tulane University School of Medicine, Department of Pediatrics, Section of Infectious Disease, New Orleans, LA, USA
| | - Robert F. Garry
- Tulane University School of Medicine, Department of Microbiology and Immunology, New Orleans, LA, USA
- Zalgen Labs, LLC, Frederick, MD, USA
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10
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Madueme PGU, Chirove F. Understanding the transmission pathways of Lassa fever: A mathematical modeling approach. Infect Dis Model 2023; 8:27-57. [PMID: 36582748 PMCID: PMC9762202 DOI: 10.1016/j.idm.2022.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/02/2022] Open
Abstract
The spread of Lassa fever infection is increasing in West Africa over the last decade. The impact of this can better be understood when considering the various possible transmission routes. We designed a mathematical model for the epidemiology of Lassa Fever using a system of nonlinear ordinary differential equations to determine the effect of transmission pathways toward the infection progression in humans and rodents including those usually neglected such as the environmental surface and aerosol routes. We analyzed the model and carried out numerical simulations to determine the impact of each transmission routes. Our results showed that the burden of Lassa fever infection is increased when all the transmission routes are incorporated and most single transmission routes are less harmful, but when in combination with other transmission routes, they increase the Lassa fever burden. It is therefore important to consider multiple transmission routes to better estimate the Lassa fever burden optimally and in turn determine control strategies targeted at the transmission pathways.
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Affiliation(s)
- Praise-God Uchechukwu Madueme
- Department of Mathematics and Applied Mathematics, University of Johannesburg, Cnr Kingsway and University Road, Auckland Park, 2092, Johannesburg, South Africa
| | - Faraimunashe Chirove
- Department of Mathematics and Applied Mathematics, University of Johannesburg, Cnr Kingsway and University Road, Auckland Park, 2092, Johannesburg, South Africa
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11
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Abstract
Lassa virus (LASV) is endemic in the rodent populations of Sierra Leone, Nigeria and other countries in West Africa. Spillover to humans occurs frequently and results in Lassa fever, a viral haemorrhagic fever (VHF) associated with a high case fatality rate. Despite advances, fundamental gaps in knowledge of the immunology, epidemiology, ecology and pathogenesis of Lassa fever persist. More frequent outbreaks, the potential for further geographic expansion of Mastomys natalensis and other rodent reservoirs, the ease of procurement and possible use and weaponization of LASV, the frequent importation of LASV to North America and Europe, and the emergence of novel LASV strains in densely populated West Africa have driven new initiatives to develop countermeasures for LASV. Although promising candidates are being evaluated, as yet there are no approved vaccines or therapeutics for human use. This Review discusses the virology of LASV, the clinical course of Lassa fever and the progress towards developing medical countermeasures.
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Affiliation(s)
- Robert F Garry
- Department of Microbiology and Immunology, Tulane University, New Orleans, LA, USA.
- Zalgen Labs, Frederick, MD, USA.
- Global Viral Network, Baltimore, MD, USA.
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12
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Abstract
Individuals living in endemic hotspots of Lassa fever have recurrent exposure to Lassa virus (LASV) via spillover from the primary host reservoir Mastomys natalensis. Despite M. natalensis being broadly distributed across sub-Saharan Africa, Lassa fever is only found in West Africa. In recent years, new LASV reservoirs have been identified. Erudition of rodent habitats, reproduction and fecundity, movement patterns, and spatial preferences are essential to institute preventative measures against Lassa fever. Evolutionary insights have also added to our knowledge of closely related mammarenavirus distribution amongst rodents throughout the continent.
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Affiliation(s)
- Allison R Smither
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, USA.
| | - Antoinette R Bell-Kareem
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, USA
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13
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Klitting R, Kafetzopoulou LE, Thiery W, Dudas G, Gryseels S, Kotamarthi A, Vrancken B, Gangavarapu K, Momoh M, Sandi JD, Goba A, Alhasan F, Grant DS, Okogbenin S, Ogbaini-Emovo E, Garry RF, Smither AR, Zeller M, Pauthner MG, McGraw M, Hughes LD, Duraffour S, Günther S, Suchard MA, Lemey P, Andersen KG, Dellicour S. Predicting the evolution of the Lassa virus endemic area and population at risk over the next decades. Nat Commun 2022; 13:5596. [PMID: 36167835 PMCID: PMC9515147 DOI: 10.1038/s41467-022-33112-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 09/02/2022] [Indexed: 01/27/2023] Open
Abstract
Lassa fever is a severe viral hemorrhagic fever caused by a zoonotic virus that repeatedly spills over to humans from its rodent reservoirs. It is currently not known how climate and land use changes could affect the endemic area of this virus, currently limited to parts of West Africa. By exploring the environmental data associated with virus occurrence using ecological niche modelling, we show how temperature, precipitation and the presence of pastures determine ecological suitability for virus circulation. Based on projections of climate, land use, and population changes, we find that regions in Central and East Africa will likely become suitable for Lassa virus over the next decades and estimate that the total population living in ecological conditions that are suitable for Lassa virus circulation may drastically increase by 2070. By analysing geotagged viral genomes using spatially-explicit phylogeography and simulating virus dispersal, we find that in the event of Lassa virus being introduced into a new suitable region, its spread might remain spatially limited over the first decades.
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Affiliation(s)
- Raphaëlle Klitting
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA.
| | - Liana E. Kafetzopoulou
- grid.5596.f0000 0001 0668 7884Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory for Clinical and Epidemiological Virology, KU Leuven - University of Leuven, Leuven, Belgium ,grid.424065.10000 0001 0701 3136Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Wim Thiery
- grid.8767.e0000 0001 2290 8069Department of Hydrology and Hydraulic Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Gytis Dudas
- grid.6441.70000 0001 2243 2806Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Sophie Gryseels
- grid.5284.b0000 0001 0790 3681Evolutionary Ecology group, Department of Biology, University of Antwerp, 2610 Antwerp, Belgium ,grid.20478.390000 0001 2171 9581Vertebrate group, Directorate Taxonomy and Phylogeny, Royal Belgian Institute of Natural Sciences, 1000 Brussels, Belgium
| | - Anjali Kotamarthi
- grid.214007.00000000122199231Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - Bram Vrancken
- grid.5596.f0000 0001 0668 7884Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory for Clinical and Epidemiological Virology, KU Leuven - University of Leuven, Leuven, Belgium
| | - Karthik Gangavarapu
- grid.214007.00000000122199231Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - Mambu Momoh
- grid.442296.f0000 0001 2290 9707Eastern Technical University of Sierra Leone, Kenema, Sierra Leone ,grid.463455.50000 0004 1799 2069Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - John Demby Sandi
- grid.463455.50000 0004 1799 2069Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Augustine Goba
- grid.463455.50000 0004 1799 2069Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Foday Alhasan
- grid.463455.50000 0004 1799 2069Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone
| | - Donald S. Grant
- grid.463455.50000 0004 1799 2069Viral Hemorrhagic Fever Program, Kenema Government Hospital, Ministry of Health and Sanitation, Kenema, Sierra Leone ,grid.442296.f0000 0001 2290 9707College of Medicine and Allied Health Sciences, University of Sierra Leone, Kenema, Sierra Leone
| | - Sylvanus Okogbenin
- grid.508091.5Irrua Specialist Teaching Hospital, Irrua, Nigeria ,grid.411357.50000 0000 9018 355XFaculty of Clinical Sciences, College of Medicine, Ambrose Alli University, Ekpoma, Nigeria
| | | | - Robert F. Garry
- grid.265219.b0000 0001 2217 8588Department of Microbiology and Immunology, Tulane University, School of Medicine, New Orleans, LA 70112 USA ,grid.505518.c0000 0004 5901 1919Zalgen Labs, LCC, Frederick, MD 21703 USA ,grid.475149.aGlobal Virus Network (GVN), Baltimore, MD 21201 USA
| | - Allison R. Smither
- grid.265219.b0000 0001 2217 8588Department of Microbiology and Immunology, Tulane University, School of Medicine, New Orleans, LA 70112 USA
| | - Mark Zeller
- grid.214007.00000000122199231Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - Matthias G. Pauthner
- grid.214007.00000000122199231Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - Michelle McGraw
- grid.214007.00000000122199231Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - Laura D. Hughes
- grid.214007.00000000122199231Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - Sophie Duraffour
- grid.424065.10000 0001 0701 3136Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany ,grid.452463.2German Center for Infection Research (DZIF), Partner site Hamburg–Lübeck–Borstel–Riems, Hamburg, Germany
| | - Stephan Günther
- grid.424065.10000 0001 0701 3136Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany ,grid.452463.2German Center for Infection Research (DZIF), Partner site Hamburg–Lübeck–Borstel–Riems, Hamburg, Germany
| | - Marc A. Suchard
- grid.19006.3e0000 0000 9632 6718Department of Biomathematics, David Geffen School of Medicine, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Department of Biostatistics, Fielding School of Public Health, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Philippe Lemey
- grid.5596.f0000 0001 0668 7884Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory for Clinical and Epidemiological Virology, KU Leuven - University of Leuven, Leuven, Belgium
| | - Kristian G. Andersen
- grid.214007.00000000122199231Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037 USA ,grid.214007.00000000122199231Scripps Research Translational Institute, La Jolla, CA 92037 USA
| | - Simon Dellicour
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory for Clinical and Epidemiological Virology, KU Leuven - University of Leuven, Leuven, Belgium. .,Spatial Epidemiology Lab (SpELL), Université Libre de Bruxelles, CP160/12 50, av. FD Roosevelt, 1050, Bruxelles, Belgium.
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14
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Nuismer SL, Basinski AJ, Schreiner C, Whitlock A, Remien CH. Reservoir population ecology, viral evolution and the risk of emerging infectious disease. Proc Biol Sci 2022; 289:20221080. [PMID: 36100013 PMCID: PMC9470272 DOI: 10.1098/rspb.2022.1080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 08/18/2022] [Indexed: 11/12/2022] Open
Abstract
The ecology and life history of wild animals influences their potential to harbour infectious disease. This observation has motivated studies identifying empirical relationships between traits of wild animals and historical patterns of spillover and emergence into humans. Although these studies have identified compelling broad-scale patterns, they are generally agnostic with respect to underlying mechanisms. Here, we develop mathematical models that couple reservoir population ecology with viral epidemiology and evolution to clarify existing verbal arguments and pinpoint the conditions that favour spillover and emergence. Our results support the idea that average lifespan influences the likelihood of an animal serving as a reservoir for human infectious disease. At the same time, however, our results show that the magnitude of this effect is sensitive to the rate of viral mutation. Our results also demonstrate that viral pathogens causing persistent infections or a transient immune response within the reservoir are more likely to fuel emergence. Genetically explicit stochastic simulations enrich these mathematical results by identifying relationships between the genetic basis of transmission and the risk of spillover and emergence. Together, our results clarify the scope of applicability for existing hypotheses and refine our understanding of emergence risk.
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Affiliation(s)
- Scott L. Nuismer
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Andrew J. Basinski
- Institute for Interdisciplinary Data Science, University of Idaho, Moscow, ID 83844, USA
| | - Courtney Schreiner
- Bioinformatics and Computational Biology, University of Idaho, Moscow, ID 83844, USA
| | - Alexander Whitlock
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Christopher H. Remien
- Department of Mathematics and Statistical Science, University of Idaho, Moscow, ID 83844, USA
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15
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Happi AN, Olumade TJ, Ogunsanya OA, Sijuwola AE, Ogunleye SC, Oguzie JU, Nwofoke C, Ugwu CA, Okoro SJ, Otuh PI, Ngele LN, Ojo OO, Adelabu A, Adeleye RF, Oyejide NE, Njaka CS, Heeney JL, Happi CT. Increased Prevalence of Lassa Fever Virus-Positive Rodents and Diversity of Infected Species Found during Human Lassa Fever Epidemics in Nigeria. Microbiol Spectr 2022; 10:e0036622. [PMID: 35913205 PMCID: PMC9430508 DOI: 10.1128/spectrum.00366-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 06/07/2022] [Indexed: 11/22/2022] Open
Abstract
The dynamics of Lassa virus (LASV) infections in rodent reservoirs and their endemic human caseloads remain poorly understood. During the endemic period, human infections are believed to be associated with the seasonal migration of Mastomys natalensis, thought to be the primary reservoir that triggers multiple spillovers of LASV to humans. It has become imperative to improve LASV diagnosis in rodents while updating their prevalence in two regions of Lassa fever endemicity in Nigeria. Rodents (total, 942) were trapped in Ondo (531) and Ebonyi (411) states between October 2018 and April 2020 for detection of LASV using various tissues. Overall, the LASV prevalence was 53.6%. The outbreak area sampled in Ondo had three and two times higher capture success and LASV prevalence, respectively, than Ebonyi State. This correlated with the higher number of annual cases of Lassa fever (LF) in Ondo State versus Ebonyi State. All rodent genera (Mastomys, Rattus, Crocidura, Mus, and Tatera) captured in both states showed slightly variable LASV positivity, with Rattus spp. being the most predominantly infected (77.3%) rodents in Ondo State versus Mastomys spp. (41.6%) in Ebonyi State. The tissues with the highest LASV positivity were the kidneys, spleen, and testes. The finding of a relatively high LASV prevalence in all of the rodent genera captured highlights the complex interspecies transmission dynamics of LASV infections in the reservoirs and their potential association with increased environmental contact, as well as the risk of zoonotic spillover in these communities, which have the highest prevalence of Lassa fever in Nigeria. IMPORTANCE Our findings show the highest LASV positivity in small rodents ever recorded and the first direct detection of LASV in Tatera spp. Our findings also indicate the abundance of LASV-infected small rodents in houses, with probable interspecies transmission through vertical and horizontal coitus routes. Consequently, we suggest that the abundance of different reservoir species for LASV may fuel the epizootic outbreaks of LF in affected human communities. The high prevalence of LASV with the diversity of affected rodents has direct implications for our understanding of the transmission risk, mitigation, and ultimately, the prevention of LF in humans. Optimal tissues for LASV detection in rodents are also presented.
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Affiliation(s)
- Anise N. Happi
- African Centre of Excellence for Genomics of Infectious Disease, Redeemer’s University, Ede, Osun, Nigeria
| | - Testimony J. Olumade
- African Centre of Excellence for Genomics of Infectious Disease, Redeemer’s University, Ede, Osun, Nigeria
- Redeemer’s University, Ede, Osun, Nigeria
| | - Olusola A. Ogunsanya
- African Centre of Excellence for Genomics of Infectious Disease, Redeemer’s University, Ede, Osun, Nigeria
| | - Ayotunde E. Sijuwola
- African Centre of Excellence for Genomics of Infectious Disease, Redeemer’s University, Ede, Osun, Nigeria
| | | | - Judith U. Oguzie
- African Centre of Excellence for Genomics of Infectious Disease, Redeemer’s University, Ede, Osun, Nigeria
- Redeemer’s University, Ede, Osun, Nigeria
| | - Cecilia Nwofoke
- Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Ebonyi, Nigeria
| | - Chinedu A. Ugwu
- African Centre of Excellence for Genomics of Infectious Disease, Redeemer’s University, Ede, Osun, Nigeria
- Redeemer’s University, Ede, Osun, Nigeria
| | - Samuel J. Okoro
- Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Ebonyi, Nigeria
| | - Patricia I. Otuh
- Michael Okpara University of Agriculture, Umudike, Abia, Nigeria
| | - Louis N. Ngele
- Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Ebonyi, Nigeria
| | | | | | | | - Nicholas E. Oyejide
- African Centre of Excellence for Genomics of Infectious Disease, Redeemer’s University, Ede, Osun, Nigeria
| | | | - Jonathan L. Heeney
- Lab of Viral Zoonotics, University of Cambridge, Cambridge, United Kingdom
| | - Christian T. Happi
- African Centre of Excellence for Genomics of Infectious Disease, Redeemer’s University, Ede, Osun, Nigeria
- Redeemer’s University, Ede, Osun, Nigeria
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16
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Soubrier H, Bangura U, Hoffmann C, Olayemi A, Adesina AS, Günther S, Oestereich L, Fichet-Calvet E. Detection of Lassa Virus-Reactive IgG Antibodies in Wild Rodents: Validation of a Capture Enzyme-Linked Immunological Assay. Viruses 2022; 14:v14050993. [PMID: 35632733 PMCID: PMC9147821 DOI: 10.3390/v14050993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 12/04/2022] Open
Abstract
The aim of this study was to evaluate the use of a capture enzyme-linked immunosorbent assay (ELISA) for the detection of LASV-reactive IgG antibodies in Mastomys rodents. The assay was used for laboratory-bred Mastomys rodents, as well as for animals caught in the wild in various regions of West Africa. The ELISA reached an accuracy of 97.1% in samples of known exposure, and a comparison to an immunofluorescence assay (IFA) revealed a very strong agreement between the ELISA and IFA results (Cohen’s kappa of 0.81). The agreement is valid in Nigeria, and in Guinea and Sierra Leone where the lineages II and IV are circulating, respectively. Altogether, these results indicate that this capture ELISA is suitable for LASV IgG serostatus determination in Mastomys rodents as an alternative to IFA. This assay will be a strong, accurate, and semi-quantitative alternative for rodent seroprevalence studies that does not depend on biosafety level 4 infrastructures, providing great benefits for ecology and epidemiology studies of Lassa fever, a disease listed on the Research and Development Blueprint of the WHO.
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Affiliation(s)
- Hugo Soubrier
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (U.B.); (C.H.); (S.G.); (L.O.)
- Correspondence: (H.S.); (E.F.-C.)
| | - Umaru Bangura
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (U.B.); (C.H.); (S.G.); (L.O.)
| | - Chris Hoffmann
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (U.B.); (C.H.); (S.G.); (L.O.)
| | - Ayodeji Olayemi
- Natural History Museum, Obafemi Awolowo University, Ile Ife HO220005, Nigeria;
| | - Adetunji Samuel Adesina
- Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, Ile Ife HO220005, Nigeria;
| | - Stephan Günther
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (U.B.); (C.H.); (S.G.); (L.O.)
- German Center for Infectious Diseases (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, 20359 Hamburg, Germany
| | - Lisa Oestereich
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (U.B.); (C.H.); (S.G.); (L.O.)
- German Center for Infectious Diseases (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, 20359 Hamburg, Germany
| | - Elisabeth Fichet-Calvet
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (U.B.); (C.H.); (S.G.); (L.O.)
- Correspondence: (H.S.); (E.F.-C.)
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Raabe V, Mehta AK, Evans JD. Lassa Virus Infection: a Summary for Clinicians. Int J Infect Dis 2022; 119:187-200. [PMID: 35395384 DOI: 10.1016/j.ijid.2022.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/01/2022] [Accepted: 04/03/2022] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVES This summary on Lassa virus (LASV) infection and Lassa fever disease (LF) was developed from a clinical perspective to provide clinicians a condensed, accessible understanding of the current literature. The information provided highlights pathogenesis, clinical features, and diagnostics with an emphasis on therapies and vaccines that have demonstrated potential value for use in clinical or research environments. METHODS An integrative literature review was conducted on the clinical and pathological features, vaccines, and treatments for LASV infection, with a focus on recent studies and in vivo evidence from humans and/or non-human primates (NHPs), when available. RESULTS Two antiviral medications with potential benefit for the treatment of LASV infection and one for post-exposure prophylaxis were identified, although a larger number of potential candidates are currently being evaluated. Multiple vaccine platforms are in pre-clinical development for LASV prevention, but data from human clinical trials are not yet available. CONCLUSION We provide succinct summaries of medical countermeasures against LASV to give the busy clinician a rapid reference. Although there are no approved drugs or vaccines for LF, we provide condensed information from a literature review for measures that can be taken when faced with a suspected infection, including investigational treatment options and hospital engineering controls.
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Affiliation(s)
- Vanessa Raabe
- New York University Grossman School of Medicine, New York, NY.
| | | | - Jared D Evans
- Johns Hopkins Applied Physics Laboratory, Laurel, MD.
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Amori G, Di Bagno E, Luiselli L. Patterns of diversity, species richness and community structure in West African savannah small mammals (rodents and shrews). TROPICAL ZOOLOGY 2021. [DOI: 10.4081/tz.2021.110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Tropical savannah ecosystems are characterized by extensive grasslands with more or less sparse trees and thickets, and are threatened globally by anthropogenic forces. These grassland habitats house a rich and diversified fauna assemblage, with some of its conspicuous elements (for instance, small mammals) that have not been sufficiently investigated so far. In this paper, we meta-analyze the literature data available on the community structure and diversity patterns of shrews and rodents in West African savannahs. Overall, 10,197 small mammal individuals belonging to 111 species of Rodentia and 55 species of Soricomorpha were found in the various studies carried out in the countries covered by the present study. Studies using a combination of methods (e.g., live trapping, pitfalls, cover boards, visual encounter) detected more species in both Soricomorpha and Rodentia, and there was a positive survey (=trap ⁄ night) effort effect on the species richness in rodents. GLM models showed (i) that there was also no effect of trapping design (transect versus grid) on species richness per site, (ii) in both rodents and soricomorphs, the number of savannah species by country depended on the total species richness of that given country, but there was no effect of the relative surface covered by savannahs in that country. The number of sympatric species per site was 2.73± 1.7 (range = 1-7) in Soricomorpha and 6.33 ± 3.8 (range 1-15) in Rodentia. Dominance index was significantly different among countries, with Nigeria having lower values than all other countries and Ghana, Benin and Sierra Leone had significantly highest values. The conservation implications of the observed patterns are discussed.
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Geographical drivers and climate-linked dynamics of Lassa fever in Nigeria. Nat Commun 2021; 12:5759. [PMID: 34599162 PMCID: PMC8486829 DOI: 10.1038/s41467-021-25910-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 09/08/2021] [Indexed: 02/08/2023] Open
Abstract
Lassa fever is a longstanding public health concern in West Africa. Recent molecular studies have confirmed the fundamental role of the rodent host (Mastomys natalensis) in driving human infections, but control and prevention efforts remain hampered by a limited baseline understanding of the disease's true incidence, geographical distribution and underlying drivers. Here, we show that Lassa fever occurrence and incidence is influenced by climate, poverty, agriculture and urbanisation factors. However, heterogeneous reporting processes and diagnostic laboratory access also appear to be important drivers of the patchy distribution of observed disease incidence. Using spatiotemporal predictive models we show that including climatic variability added retrospective predictive value over a baseline model (11% decrease in out-of-sample predictive error). However, predictions for 2020 show that a climate-driven model performs similarly overall to the baseline model. Overall, with ongoing improvements in surveillance there may be potential for forecasting Lassa fever incidence to inform health planning.
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Hoffmann C, Wurr S, Pallasch E, Bockholt S, Rieger T, Günther S, Oestereich L. Experimental Morogoro Virus Infection in Its Natural Host, Mastomys natalensis. Viruses 2021; 13:851. [PMID: 34067011 PMCID: PMC8151005 DOI: 10.3390/v13050851] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/27/2021] [Accepted: 04/30/2021] [Indexed: 01/26/2023] Open
Abstract
Natural hosts of most arenaviruses are rodents. The human-pathogenic Lassa virus and several non-pathogenic arenaviruses such as Morogoro virus (MORV) share the same host species, namely Mastomys natalensis (M. natalensis). In this study, we investigated the history of infection and virus transmission within the natural host population. To this end, we infected M. natalensis at different ages with MORV and measured the health status of the animals, virus load in blood and organs, the development of virus-specific antibodies, and the ability of the infected individuals to transmit the virus. To explore the impact of the lack of evolutionary virus-host adaptation, experiments were also conducted with Mobala virus (MOBV), which does not share M. natalensis as a natural host. Animals infected with MORV up to two weeks after birth developed persistent infection, seroconverted and were able to transmit the virus horizontally. Animals older than two weeks at the time of infection rapidly cleared the virus. In contrast, MOBV-infected neonates neither developed persistent infection nor were able to transmit the virus. In conclusion, we demonstrate that MORV is able to develop persistent infection in its natural host, but only after inoculation shortly after birth. A related arenavirus that is not evolutionarily adapted to M. natalensis is not able to establish persistent infection. Persistently infected animals appear to be important to maintain virus transmission within the host population.
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Affiliation(s)
- Chris Hoffmann
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (C.H.); (S.W.); (E.P.); (S.B.); (T.R.); (S.G.)
| | - Stephanie Wurr
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (C.H.); (S.W.); (E.P.); (S.B.); (T.R.); (S.G.)
| | - Elisa Pallasch
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (C.H.); (S.W.); (E.P.); (S.B.); (T.R.); (S.G.)
- German Center for Infectious Diseases (DZIF), Partner Site Hamburg, Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Sabrina Bockholt
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (C.H.); (S.W.); (E.P.); (S.B.); (T.R.); (S.G.)
- German Center for Infectious Diseases (DZIF), Partner Site Hamburg, Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Toni Rieger
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (C.H.); (S.W.); (E.P.); (S.B.); (T.R.); (S.G.)
| | - Stephan Günther
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (C.H.); (S.W.); (E.P.); (S.B.); (T.R.); (S.G.)
- German Center for Infectious Diseases (DZIF), Partner Site Hamburg, Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Lisa Oestereich
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (C.H.); (S.W.); (E.P.); (S.B.); (T.R.); (S.G.)
- German Center for Infectious Diseases (DZIF), Partner Site Hamburg, Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
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21
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Arruda LB, Haider N, Olayemi A, Simons D, Ehichioya D, Yinka-Ogunleye A, Ansumana R, Thomason MJ, Asogun D, Ihekweazu C, Fichet-Calvet E, Kock RA. The niche of One Health approaches in Lassa fever surveillance and control. Ann Clin Microbiol Antimicrob 2021; 20:29. [PMID: 33894784 PMCID: PMC8067790 DOI: 10.1186/s12941-021-00431-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 04/12/2021] [Indexed: 12/20/2022] Open
Abstract
Lassa fever (LF), a zoonotic illness, represents a public health burden in West African countries where the Lassa virus (LASV) circulates among rodents. Human exposure hinges significantly on LASV ecology, which is in turn shaped by various parameters such as weather seasonality and even virus and rodent-host genetics. Furthermore, human behaviour, despite playing a key role in the zoonotic nature of the disease, critically affects either the spread or control of human-to-human transmission. Previous estimations on LF burden date from the 80s and it is unclear how the population expansion and the improvement on diagnostics and surveillance methods have affected such predictions. Although recent data have contributed to the awareness of epidemics, the real impact of LF in West African communities will only be possible with the intensification of interdisciplinary efforts in research and public health approaches. This review discusses the causes and consequences of LF from a One Health perspective, and how the application of this concept can improve the surveillance and control of this disease in West Africa.
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Affiliation(s)
- Liã Bárbara Arruda
- Centre for Clinical Microbiology, Division of Infection and Immunity, University College London, London, UK.
| | - Najmul Haider
- The Royal Veterinary College, University of London, Hatfield, UK
| | - Ayodeji Olayemi
- Natural History Museum, Obafemi Awolowo University, Ile Ife, Nigeria
| | - David Simons
- The Royal Veterinary College, University of London, Hatfield, UK
| | - Deborah Ehichioya
- Institute of Lassa Fever Research and Control, Irrua Specialist Teaching Hospital, Irrua, Nigeria.,Department of Microbiology, Ambrose Alli University, Ekpoma, Nigeria
| | | | - Rashid Ansumana
- School of Community Health Sciences, Njala University, Bo, Sierra Leone
| | - Margaret J Thomason
- Centre for Clinical Microbiology, Division of Infection and Immunity, University College London, London, UK
| | - Danny Asogun
- Institute of Lassa Fever Research and Control, Irrua Specialist Teaching Hospital, Irrua, Nigeria
| | | | | | - Richard A Kock
- The Royal Veterinary College, University of London, Hatfield, UK
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22
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Basinski AJ, Fichet-Calvet E, Sjodin AR, Varrelman TJ, Remien CH, Layman NC, Bird BH, Wolking DJ, Monagin C, Ghersi BM, Barry PA, Jarvis MA, Gessler PE, Nuismer SL. Bridging the gap: Using reservoir ecology and human serosurveys to estimate Lassa virus spillover in West Africa. PLoS Comput Biol 2021; 17:e1008811. [PMID: 33657095 PMCID: PMC7959400 DOI: 10.1371/journal.pcbi.1008811] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 03/15/2021] [Accepted: 02/17/2021] [Indexed: 01/07/2023] Open
Abstract
Forecasting the risk of pathogen spillover from reservoir populations of wild or domestic animals is essential for the effective deployment of interventions such as wildlife vaccination or culling. Due to the sporadic nature of spillover events and limited availability of data, developing and validating robust, spatially explicit, predictions is challenging. Recent efforts have begun to make progress in this direction by capitalizing on machine learning methodologies. An important weakness of existing approaches, however, is that they generally rely on combining human and reservoir infection data during the training process and thus conflate risk attributable to the prevalence of the pathogen in the reservoir population with the risk attributed to the realized rate of spillover into the human population. Because effective planning of interventions requires that these components of risk be disentangled, we developed a multi-layer machine learning framework that separates these processes. Our approach begins by training models to predict the geographic range of the primary reservoir and the subset of this range in which the pathogen occurs. The spillover risk predicted by the product of these reservoir specific models is then fit to data on realized patterns of historical spillover into the human population. The result is a geographically specific spillover risk forecast that can be easily decomposed and used to guide effective intervention. Applying our method to Lassa virus, a zoonotic pathogen that regularly spills over into the human population across West Africa, results in a model that explains a modest but statistically significant portion of geographic variation in historical patterns of spillover. When combined with a mechanistic mathematical model of infection dynamics, our spillover risk model predicts that 897,700 humans are infected by Lassa virus each year across West Africa, with Nigeria accounting for more than half of these human infections. The 2019 emergence of SARS-CoV-2 is a grim reminder of the threat animal-borne pathogens pose to human health. Even prior to SARS-CoV-2, the spillover of pathogens from animal reservoirs was a persistent problem, with pathogens such as Ebola, Nipah, and Lassa regularly but unpredictably causing outbreaks. Machine-learning models that anticipate when and where pathogen transmission from animals to humans is likely to occur would help guide surveillance efforts and preemptive countermeasures like information campaigns or vaccination programs. We develop a novel machine learning framework that uses datasets describing the distribution of a virus within its host and the range of its animal host, along with data on spatial patterns of human immunity, to infer rates of animal-to-human transmission across a region. By training the model on data from the animal host alone, our framework allows rigorous validation of spillover predictions using human data. We apply our framework to Lassa fever, a viral disease of West Africa that is spread to humans by rodents, and use the predictions to update estimates of Lassa virus infections in humans. Our results suggest that Nigeria is most at risk for the emergence of Lassa virus, and should be prioritized for outbreak-surveillance.
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Affiliation(s)
- Andrew J. Basinski
- Department of Mathematics, University of Idaho, Moscow, Idaho, United States of America
- * E-mail:
| | | | - Anna R. Sjodin
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Tanner J. Varrelman
- Bioinformatics and Computational Biology, University of Idaho, Moscow, Idaho, United States of America
| | - Christopher H. Remien
- Department of Mathematics, University of Idaho, Moscow, Idaho, United States of America
| | - Nathan C. Layman
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Brian H. Bird
- One Health Institute, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - David J. Wolking
- One Health Institute, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Corina Monagin
- One Health Institute, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Bruno M. Ghersi
- One Health Institute, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Peter A. Barry
- Center for Comparative Medicine, California National Primate Research Center, Department of Pathology and Laboratory Medicine, University of California, Davis, California, United States of America
| | - Michael A. Jarvis
- School of Biomedical and Healthcare Sciences, University of Plymouth, Plymouth, United Kingdom
| | - Paul E. Gessler
- College of Natural Resources, University of Idaho, Moscow, Idaho, United States of America
| | - Scott L. Nuismer
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
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23
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Akpogheneta O, Dicks S, Grant D, Kanneh Z, Jusu B, Edem-Hotah J, Kanneh L, Alhasan F, Gbakie M, Schieffelin J, Ijaz S, Tedder R, Bower H. Boosting understanding of Lassa Fever virus epidemiology: Field testing a novel assay to identify past Lassa Fever virus infection in blood and oral fluids of survivors and unexposed controls in Sierra Leone. PLoS Negl Trop Dis 2021; 15:e0009255. [PMID: 33788861 PMCID: PMC8041174 DOI: 10.1371/journal.pntd.0009255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 04/12/2021] [Accepted: 02/18/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Despite identification 50 years ago, the true burden of Lassa Fever (LF) across Africa remains undefined for reasons including research focus on hospitalised patients, lack of validated field-feasible tools which reliably identify past infection, and the fact that all assays require blood samples making large-scale surveys difficult. Designated a priority pathogen of epidemic potential requiring urgent research by the World Health Organisation, a better understanding of LF sero-epidemiology is essential to developing and evaluating new interventions including vaccines. We describe the first field testing of a novel species-neutral Double Antigen Binding Assay (DABA) designed to detect antibodies to LF in plasma and oral fluid. METHODOLOGY/PRINCIPAL FINDINGS Paired plasma and oral fluid were collected in Sierra Leone from survivors discharged from Kenema Government Hospital Lassa Fever Unit between 1980 and 2018, and from controls recruited in Freetown in 2019. Epidemiological sensitivity and specificity of the DABA measured against historical diagnosis in survivors and self-declared non-exposed controls was 81.7% (95% CI 70.7%- 89.9%) and 83.3% (72.7%- 91.1%) respectively in plasma, and 71.8% (60.0%- 81.9%) and 83.3% (72.7%- 91.1%) respectively in oral fluid. Antibodies were identified in people infected up to 15 years and, in one case, 40 years previously. Participants found oral fluid collection easy and painless with 80% happy to give an oral fluid sample regularly. CONCLUSIONS/SIGNIFICANCE Given the difficulties of assay validation in a resource-limited setting, including unexpected exposures and diagnostics of varying accuracy, the new assay performed well in both plasma and oral fluid. Sensitivity and specificity are expected to be higher when case/control ascertainment is more definitive and further work is planned to investigate this. Even at the performance levels achieved, the species-neutral DABA has the potential to facilitate the large-scale seroprevalence surveys needed to underpin essential developments in LF control, as well as support zoonotic investigations.
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Affiliation(s)
- Onome Akpogheneta
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Steve Dicks
- Blood Borne Virus Unit, Public Health England, Colindale, United Kingdom
- Microbiology Services, NHS Blood and Transplant, London, United Kingdom
| | - Donald Grant
- Kenema Government Hospital Lassa Fever Unit, Kenema, Sierra Leone
| | - Zainab Kanneh
- Kenema Government Hospital Lassa Fever Unit, Kenema, Sierra Leone
| | - Brima Jusu
- Kenema Government Hospital Lassa Fever Unit, Kenema, Sierra Leone
| | - Joseph Edem-Hotah
- Faculty of Nursing, University of Sierra Leone, Freetown, Sierra Leone
| | - Lansana Kanneh
- Kenema Government Hospital Lassa Fever Unit, Kenema, Sierra Leone
| | - Foday Alhasan
- Kenema Government Hospital Lassa Fever Unit, Kenema, Sierra Leone
| | - Michael Gbakie
- Kenema Government Hospital Lassa Fever Unit, Kenema, Sierra Leone
| | - John Schieffelin
- Sections of Infectious Disease, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Samreen Ijaz
- Blood Borne Virus Unit, Public Health England, Colindale, United Kingdom
| | - Richard Tedder
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Hilary Bower
- UK Public Health Rapid Support Team, London School of Hygiene & Tropical Medicine/Public Health England, London, United Kingdom
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24
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Lassa Virus Circulation in Small Mammal Populations in Bo District, Sierra Leone. BIOLOGY 2021; 10:biology10010028. [PMID: 33466234 PMCID: PMC7824740 DOI: 10.3390/biology10010028] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/21/2020] [Accepted: 12/28/2020] [Indexed: 11/26/2022]
Abstract
Simple Summary Lassa fever is a viral hemorrhagic fever caused by the Lassa virus (LASV). It is a deadly rodent-borne zoonosis with outbreaks occurring mostly in Sierra Leone, Guinea, Liberia, and Nigeria, in West Africa. In Sierra Leone, surveillance activities of LASV focus mainly on the Kenema area in the eastern region, known to be the epicentre. Little is known about the presence of the virus in the Bo area, where Mastomys natalensis and Rattus rattus share habitats with humans. Our study investigated the circulation and phylogeny of new LASV strains and virus seroprevalence in rodent populations of villages in Bo district. Information provided here will be of great importance in prioritizing areas for Lassa fever surveillance and preventive measures to mitigate future outbreaks. Our rodent longitudinal survey carried out over two years (2014–2016) identified Mastomys natalensis as the most prevalent species. While seropositive small mammals were found in every village, the four Mastomys natalensis rodents that tested PCR-positive for Lassa virus were found in only two villages. Phylogenetic analysis showed that these sequences belong to the Sierra Leonean clade, within lineage IV. In conclusion, LASV is present, with low circulation, in small mammals in rural settings around Bo. Abstract Lassa fever is a viral hemorrhagic fever caused by the Lassa virus LASV, which was first isolated in the rodent Mastomys natalensis in 1974 in Kenema, Sierra Leone. As little is known about the abundance and the presence of LASV in rodents living in the Bo area, we carried out a small mammal longitudinal population survey. A standardized trapping session was performed in various habitats and seasons in six villages over two years (2014–2016) and samples collected were tested for arenavirus IgG and LASV. A Bayesian phylogenetic analysis was performed on sequences identified by PCR. A total of 1490 small mammals were collected, and 16 rodent species were identified, with M. natalensis (355, 24%) found to be the most prevalent species. Forty-one (2.8%) samples were IgG positive, and 31 of these were trapped in homes and 10 in surrounding vegetation. Twenty-nine of 41 seropositive rodents were M. natalensis. We detected four LASV by PCR in two villages, all found in M. natalensis. Phylogenetic analysis showed that the sequences were distributed within the Sierra Leonean clade within lineage IV, distinguishing a Bo sub-clade older than a Kenema sub-clade. Compared to other settings, we found a low abundance of M. natalensis and a low circulation of LASV in rodents in villages around Bo district.
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25
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Mariën J, Lo Iacono G, Rieger T, Magassouba N, Günther S, Fichet-Calvet E. Households as hotspots of Lassa fever? Assessing the spatial distribution of Lassa virus-infected rodents in rural villages of Guinea. Emerg Microbes Infect 2020; 9:1055-1064. [PMID: 32459576 PMCID: PMC7336995 DOI: 10.1080/22221751.2020.1766381] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/24/2020] [Accepted: 05/02/2020] [Indexed: 01/25/2023]
Abstract
The Natal multimammate mouse (Mastomys natalensis) is the reservoir host of Lassa virus (LASV), an arenavirus that causes Lassa haemorrhagic fever in humans in West Africa. While previous studies suggest that spillover risk is focal within rural villages due to the spatial behaviour of the rodents, the level of clustering was never specifically assessed. Nevertheless, detailed information on the spatial distribution of infected rodents would be highly valuable to optimize LASV-control campaigns, which are limited to rodent control or interrupting human-rodent contact considering that a human vaccine is not available. Here, we analysed data from a four-year field experiment to investigate whether LASV-infected rodents cluster in households in six rural villages in Guinea. Our analyses were based on the infection status (antibody or PCR) and geolocation of rodents (n = 864), and complemented with a phylogenetic analysis of LASV sequences (n = 119). We observed that the majority of infected rodents were trapped in a few houses (20%) and most houses were rodent-free at a specific point in time (60%). We also found that LASV strains circulating in a specific village were polyphyletic with respect to neighbouring villages, although most strains grouped together at the sub-village level and persisted over time. In conclusion, our results suggest that: (i) LASV spillover risk is heterogeneously distributed within villages in Guinea; (ii) viral elimination in one particular village is unlikely if rodents are not controlled in neighbouring villages. Such spatial information should be incorporated into eco-epidemiological models that assess the cost-efficiency of LASV control strategies.
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Affiliation(s)
- Joachim Mariën
- Department of Clinical Sciences/Outbreak Research Team, Institute of Tropical Medicine, Antwerp, Belgium
| | | | - Toni Rieger
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | | | - Stephan Günther
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
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26
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Bayesian estimation of Lassa virus epidemiological parameters: Implications for spillover prevention using wildlife vaccination. PLoS Negl Trop Dis 2020; 14:e0007920. [PMID: 32956349 PMCID: PMC7529244 DOI: 10.1371/journal.pntd.0007920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 10/01/2020] [Accepted: 07/20/2020] [Indexed: 12/31/2022] Open
Abstract
Lassa virus is a significant burden on human health throughout its endemic region in West Africa, with most human infections the result of spillover from the primary rodent reservoir of the virus, the natal multimammate mouse, M. natalensis. Here we develop a Bayesian methodology for estimating epidemiological parameters of Lassa virus within its rodent reservoir and for generating probabilistic predictions for the efficacy of rodent vaccination programs. Our approach uses Approximate Bayesian Computation (ABC) to integrate mechanistic mathematical models, remotely-sensed precipitation data, and Lassa virus surveillance data from rodent populations. Using simulated data, we show that our method accurately estimates key model parameters, even when surveillance data are available from only a relatively small number of points in space and time. Applying our method to previously published data from two villages in Guinea estimates the time-averaged R0 of Lassa virus to be 1.74 and 1.54 for rodent populations in the villages of Bantou and Tanganya, respectively. Using the posterior distribution for model parameters derived from these Guinean populations, we evaluate the likely efficacy of vaccination programs relying on distribution of vaccine-laced baits. Our results demonstrate that effective and durable reductions in the risk of Lassa virus spillover into the human population will require repeated distribution of large quantities of vaccine. Lassa virus is a chronic source of illness throughout West Africa, and is considered to be a threat for widespread emergence. Because most human infections result from contact with infected rodents, interventions that reduce the number of rodents infected with Lassa virus represent promising opportunities for reducing the public health burden of this disease. Evaluating how well alternative interventions are likely to perform is complicated by our relatively poor understanding of viral epidemiology within the reservoir population. Here we develop a novel statistical approach that couples mathematical models and viral surveillance data from rodent populations to robustly estimate key epidemiological parameters. Applying our method to existing data from Guinea yields well-resolved parameter estimates and allows us to simulate a variety of rodent vaccination programs. Together, our results demonstrate that rodent vaccination alone is unlikely to be an effective tool for reducing the public health burden of Lassa fever within West Africa.
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27
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Kenmoe S, Tchatchouang S, Ebogo-Belobo JT, Ka'e AC, Mahamat G, Guiamdjo Simo RE, Bowo-Ngandji A, Demeni Emoh CP, Che E, Tchami Ngongang D, Amougou-Atsama M, Nzukui ND, Mbongue Mikangue CA, Mbaga DS, Kenfack S, Kingue Bebey SR, Amvongo Adjia N, Efietngab AN, Tazokong HR, Modiyinji AF, Kengne-Nde C, Sadeuh-Mba SA, Njouom R. Systematic review and meta-analysis of the epidemiology of Lassa virus in humans, rodents and other mammals in sub-Saharan Africa. PLoS Negl Trop Dis 2020; 14:e0008589. [PMID: 32845889 PMCID: PMC7478710 DOI: 10.1371/journal.pntd.0008589] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 09/08/2020] [Accepted: 07/13/2020] [Indexed: 12/27/2022] Open
Abstract
Accurate data on the Lassa virus (LASV) human case fatality rate (CFR) and the prevalence of LASV in humans, rodents and other mammals are needed for better planning of actions that will ultimately reduce the burden of LASV infection in sub-Saharan Africa. In this systematic review with meta-analysis, we searched PubMed, Scopus, Africa Journal Online, and African Index Medicus from 1969 to 2020 to obtain studies that reported enough data to calculate LASV infection CFR or prevalence. Study selection, data extraction, and risk of bias assessment were conducted independently. We extracted all measures of current, recent, and past infections with LASV. Prevalence and CFR estimates were pooled using a random-effect meta-analysis. Factors associated with CFR, prevalence, and sources of between-study heterogeneity were determined using subgroup and metaregression analyses. This review was registered with PROSPERO, CRD42020166465. We initially identified 1,399 records and finally retained 109 reports that contributed to 291 prevalence records from 25 countries. The overall CFR was 29.7% (22.3-37.5) in humans. Pooled prevalence of LASV infection was 8.7% (95% confidence interval: 6.8-10.8) in humans, 3.2% (1.9-4.6) in rodents, and 0.7% (0.0-2.3) in other mammals. Subgroup and metaregression analyses revealed a substantial statistical heterogeneity explained by higher prevalence in tissue organs, in case-control, in hospital outbreak, and surveys, in retrospective studies, in urban and hospital setting, in hospitalized patients, and in West African countries. This study suggests that LASV infections is an important cause of death in humans and that LASV are common in humans, rodents and other mammals in sub-Saharan Africa. These estimates highlight disparities between sub-regions, and population risk profiles. Western Africa, and specific key populations were identified as having higher LASV CFR and prevalence, hence, deserving more attention for cost-effective preventive interventions.
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Affiliation(s)
- Sebastien Kenmoe
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
| | | | - Jean Thierry Ebogo-Belobo
- Medical Research Centre, Institut of Medical Research and Medicinal Plants Studies, Yaoundé, Cameroon
| | - Aude Christelle Ka'e
- Virology Department, Chantal Biya International Reference Centre, Yaoundé, Cameroon
| | - Gadji Mahamat
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | | | - Arnol Bowo-Ngandji
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | | | - Emmanuel Che
- Vaccinology and Biobank, Chantal Biya International Reference Centre, Yaounde, Cameroon
| | - Dimitri Tchami Ngongang
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | - Marie Amougou-Atsama
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
- Medical Research Centre, Institut of Medical Research and Medicinal Plants Studies, Yaoundé, Cameroon
| | - Nathalie Diane Nzukui
- School of Health Sciences-Catholic University of Central Africa, Department of Medical Microbiology, Yaoundé, Cameroon
| | | | - Donatien Serge Mbaga
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | - Sorel Kenfack
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | | | - Nathalie Amvongo Adjia
- Medical Research Centre, Institut of Medical Research and Medicinal Plants Studies, Yaoundé, Cameroon
| | - Atembeh Noura Efietngab
- Medical Research Centre, Institut of Medical Research and Medicinal Plants Studies, Yaoundé, Cameroon
| | - Hervé Raoul Tazokong
- Department of Microbiology, Faculty of Science, The University of Yaounde I, Yaoundé, Cameroon
| | - Abdou Fatawou Modiyinji
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
- Department of Animals Biology and Physiology, Faculty of Science, The University of Yaoundé I, Yaoundé, Cameroon
| | - Cyprien Kengne-Nde
- Epidemiological Surveillance, Evaluation and Research Unit, National AIDS Control Committee, Yaoundé, Cameroon
| | | | - Richard Njouom
- Department of Virology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
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Schmaljohn C, Safronetz D. Editorial overview: Lassa virus. Curr Opin Virol 2020; 37:vii-ix. [PMID: 31564289 DOI: 10.1016/j.coviro.2019.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Connie Schmaljohn
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, United States.
| | - David Safronetz
- Special Pathogens, Public Health Agency of Canada - National Microbiology Laboratory, Winnipeg, Manitoba, R3E 3P6, Canada.
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29
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Cuypers LN, Baird SJE, Hánová A, Locus T, Katakweba AS, Gryseels S, Bryja J, Leirs H, Goüy de Bellocq J. Three arenaviruses in three subspecific natal multimammate mouse taxa in Tanzania: same host specificity, but different spatial genetic structure? Virus Evol 2020; 6:veaa039. [PMID: 33033629 PMCID: PMC7532547 DOI: 10.1093/ve/veaa039] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Mastomys natalensis is widespread in sub-Saharan Africa and hosts several arenavirus species, including the pathogenic zoonotic Lassa virus in West Africa. Mitochondrial lineages sub-divide the range of M. natalensis and have been associated with cryptic structure within the species. To test specificity of arenaviruses to hosts carrying these lineages, we screened 1772 M. natalensis in a large area of Tanzania where three mitochondrial lineages meet. We detected fifty-two individuals that were positive for one of three arenaviruses: Gairo, Morogoro, and Luna virus. This is the first record of Luna virus in Tanzania. We confirmed the specificity of each arenavirus to a distinct host mitochondrial lineage except for three cases in one locality at the centre of a host hybrid zone. No arenaviruses were detected in a large part of the study area. Morogoro and Gairo virus showed differences in prevalence (Morogoro virus lower than Gairo virus) and in genetic structure (Morogoro virus more structured than Gairo virus). However, both viruses have genetic neighbourhood size estimates of the same order of magnitude as Lassa virus. While differences in arenavirus and/or host evolutionary and ecological dynamics may exist, Tanzanian arenaviruses could be suited to model Lassa virus dynamics in M. natalensis.
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Affiliation(s)
- Laura N Cuypers
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Stuart J E Baird
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic
| | - Alexandra Hánová
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic.,Department of Botany and Zoology, Masaryk University, Brno, Czech Republic
| | - Tatjana Locus
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Abdul S Katakweba
- Pest Management Centre, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Sophie Gryseels
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium.,Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA.,Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Leuven, Belgium
| | - Josef Bryja
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic.,Department of Botany and Zoology, Masaryk University, Brno, Czech Republic
| | - Herwig Leirs
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
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30
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Akhmetzhanov AR, Asai Y, Nishiura H. Quantifying the seasonal drivers of transmission for Lassa fever in Nigeria. Philos Trans R Soc Lond B Biol Sci 2020; 374:20180268. [PMID: 31056054 PMCID: PMC6553602 DOI: 10.1098/rstb.2018.0268] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Lassa fever (LF) is a zoonotic disease that is widespread in West Africa and involves animal-to-human and human-to-human transmission. Animal-to-human transmission occurs upon exposure to rodent excreta and secretions, i.e. urine and saliva, and human-to-human transmission occurs via the bodily fluids of an infected person. To elucidate the seasonal drivers of LF epidemics, we employed a mathematical model to analyse the datasets of human infection, rodent population dynamics and climatological variations and capture the underlying transmission dynamics. The surveillance-based incidence data of human cases in Nigeria were explored, and moreover, a mathematical model was used for describing the transmission dynamics of LF in rodent populations. While quantifying the case fatality risk and the rate of exposure of humans to animals, we explicitly estimated the corresponding contact rate of humans with infected rodents, accounting for the seasonal population dynamics of rodents. Our findings reveal that seasonal migratory dynamics of rodents play a key role in regulating the cyclical pattern of LF epidemics. The estimated timing of high exposure of humans to animals coincides with the time shortly after the start of the dry season and can be associated with the breeding season of rodents in Nigeria. This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’. This issue is linked with the subsequent theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’.
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Affiliation(s)
| | - Yusuke Asai
- Graduate School of Medicine, Hokkaido University , Sapporo, Hokkaido , Japan
| | - Hiroshi Nishiura
- Graduate School of Medicine, Hokkaido University , Sapporo, Hokkaido , Japan
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31
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Olayemi A, Fichet-Calvet E. Systematics, Ecology, and Host Switching: Attributes Affecting Emergence of the Lassa Virus in Rodents across Western Africa. Viruses 2020; 12:E312. [PMID: 32183319 PMCID: PMC7150792 DOI: 10.3390/v12030312] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 12/18/2022] Open
Abstract
Ever since it was established that rodents serve as reservoirs of the zoonotic Lassa virus (LASV), scientists have sought to answer the questions: which populations of rodents carry the virus? How do fluctuations in LASV prevalence and rodent abundance influence Lassa fever outbreaks in humans? What does it take for the virus to adopt additional rodent hosts, proliferating what already are devastating cycles of rodent-to-human transmission? In this review, we examine key aspects of research involving the biology of rodents that affect their role as LASV reservoirs, including phylogeography, demography, virus evolution, and host switching. We discuss how this knowledge can help control Lassa fever and suggest further areas for investigation.
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Affiliation(s)
- Ayodeji Olayemi
- Natural History Museum, Obafemi Awolowo University, Ile Ife HO220005, Nigeria;
| | - Elisabeth Fichet-Calvet
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany
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32
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Schreiner CL, Nuismer SL, Basinski AJ. When to vaccinate a fluctuating wildlife population: Is timing everything? J Appl Ecol 2020; 57:307-319. [PMID: 32139945 PMCID: PMC7043377 DOI: 10.1111/1365-2664.13539] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 10/27/2019] [Indexed: 02/06/2023]
Abstract
Wildlife vaccination is an important tool for managing the burden of infectious disease in human populations, domesticated livestock and various iconic wildlife. Although substantial progress has been made in the field of vaccine designs for wildlife, there is a gap in our understanding of how to time wildlife vaccination, relative to host demography, to best protect a population.We use a mathematical model and computer simulations to assess the outcomes of vaccination campaigns that deploy vaccines once per annual population cycle.Optimal timing of vaccination is an important consideration in animals with short to intermediate life spans and a short birthing season. Vaccines that are deployed shortly after the birthing season best protect the host population.The importance of timing is greater in wildlife pathogens that have a high rate of transmission and a short recovery period. Vaccinating at the end of the birthing season best reduces the mean abundance of pathogen-infected hosts. Delaying vaccination until later in the year can facilitate pathogen elimination. Policy Implications. Tuning wildlife vaccination campaigns to host demography and pathogen traits can substantially increase the effectiveness of a campaign. Our results suggest that, for a fluctuating population, vaccinating at, or shortly after, the end of the birthing season, best protects the population against an invading pathogen. If the pathogen is already endemic, delaying vaccination until after the birthing season is over can help facilitate pathogen elimination. Our results highlight the need to better understand and predict host demography in wildlife populations that are targeted for vaccination.
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33
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Native and Invasive Small Mammals in Urban Habitats along the Commercial Axis Connecting Benin and Niger, West Africa. DIVERSITY 2019. [DOI: 10.3390/d11120238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Based on compiled small mammal trapping data collected over 12 years from Benin and Niger (3701 individual records from 66 sampling sites), located in mainland Africa, we here describe the small mammal community assemblage in urban habitats along the commercial axis connecting the two countries, from the seaport of Cotonou to the Sahelian hinterland, with a particular focus on invasive species. In doing so, we document extant species distributions, which highlight the risks of continuing the range expansion of three synanthropic invasive rodent species, namely black rats (Rattus rattus), brown rats (R. norvegicus), and house mice (Mus musculus). Using various diversity estimates and community ecology approaches, we detect a latitudinal gradient of species richness that significantly decreased Northward. We show that shrews (Crocidura) represent a very important component of micro-mammal fauna in West African towns and villages, especially at lower latitudes. We also demonstrate that invasive and native synanthropic rodents do not distribute randomly in West Africa, which suggests that invasive species dynamics and history differ markedly, and that they involve gradual, as well as human-mediated, long distance dispersal. Patterns of segregation are also observed between native Mastomys natalensis and invasive rats R. rattus and R. norvegicus, suggesting potential native-to-invasive species turn over. Consequences of such processes, especially in terms of public health, are discussed.
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34
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Mariën J, Borremans B, Verhaeren C, Kirkpatrick L, Gryseels S, Goüy de Bellocq J, Günther S, Sabuni CA, Massawe AW, Reijniers J, Leirs H. Density dependence and persistence of Morogoro arenavirus transmission in a fluctuating population of its reservoir host. J Anim Ecol 2019; 89:506-518. [PMID: 31545505 DOI: 10.1111/1365-2656.13107] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 07/21/2019] [Indexed: 11/28/2022]
Abstract
A key aim in wildlife disease ecology is to understand how host and parasite characteristics influence parasite transmission and persistence. Variation in host population density can have strong impacts on transmission and outbreaks, and theory predicts particular transmission-density patterns depending on how parasites are transmitted between individuals. Here, we present the results of a study on the dynamics of Morogoro arenavirus in a population of multimammate mice (Mastomys natalensis). This widespread African rodent, which is also the reservoir host of Lassa arenavirus in West Africa, is known for its strong seasonal density fluctuations driven by food availability. We investigated to what degree virus transmission changes with host population density and how the virus might be able to persist during periods of low host density. A seven-year capture-mark-recapture study was conducted in Tanzania where rodents were trapped monthly and screened for the presence of antibodies against Morogoro virus. Observed seasonal seroprevalence patterns were compared with those generated by mathematical transmission models to test different hypotheses regarding the degree of density dependence and the role of chronically infected individuals. We observed that Morogoro virus seroprevalence correlates positively with host density with a lag of 1-4 months. Model results suggest that the observed seasonal seroprevalence dynamics can be best explained by a combination of vertical and horizontal transmission and that a small number of animals need to be infected chronically to ensure viral persistence. Transmission dynamics and viral persistence were best explained by the existence of both acutely and chronically infected individuals and by seasonally changing transmission rates. Due to the presence of chronically infected rodents, rodent control is unlikely to be a feasible approach for eliminating arenaviruses such as Lassa virus from Mastomys populations.
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Affiliation(s)
- Joachim Mariën
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | - Benny Borremans
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, LA, USA.,Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-BIOSTAT), Hasselt University, Hasselt, Belgium
| | | | | | - Sophie Gryseels
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium.,Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA.,Clinical and Epidemiological Virology, Rega Institute, KU Leuven, Leuven, Belgium
| | - Joëlle Goüy de Bellocq
- Institute of Vertebrate Biology, Research Facility Studenec, The Czech Academy of Sciences, Brno, Czech Republic
| | - Stephan Günther
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | | | - Apia W Massawe
- PestManagement Centre, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Jonas Reijniers
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium.,Department of Engineering Management, University of Antwerp, Antwerp, Belgium
| | - Herwig Leirs
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
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Khalil H, Ecke F, Evander M, Bucht G, Hörnfeldt B. Population Dynamics of Bank Voles Predicts Human Puumala Hantavirus Risk. ECOHEALTH 2019; 16:545-557. [PMID: 31309365 PMCID: PMC6858908 DOI: 10.1007/s10393-019-01424-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 05/15/2019] [Accepted: 05/15/2019] [Indexed: 06/01/2023]
Abstract
Predicting risk of zoonotic diseases, i.e., diseases shared by humans and animals, is often complicated by the population ecology of wildlife host(s). We here demonstrate how ecological knowledge of a disease system can be used for early prediction of human risk using Puumala hantavirus (PUUV) in bank voles (Myodes glareolus), which causes Nephropathia epidemica (NE) in humans, as a model system. Bank vole populations at northern latitudes exhibit multiannual fluctuations in density and spatial distribution, a phenomenon that has been studied extensively. Nevertheless, existing studies predict NE incidence only a few months before an outbreak. We used a time series on cyclic bank vole population density (1972-2013), their PUUV infection rates (1979-1986; 2003-2013), and NE incidence in Sweden (1990-2013). Depending on the relationship between vole density and infection prevalence (proportion of infected animals), either overall density of bank voles or the density of infected bank voles may be used to predict seasonal NE incidence. The density and spatial distribution of voles at density minima of a population cycle contribute to the early warning of NE risk later at its cyclic peak. When bank voles remain relatively widespread in the landscape during cyclic minima, PUUV can spread from a high baseline during a cycle, culminating in high prevalence in bank voles and potentially high NE risk during peak densities.
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Affiliation(s)
- Hussein Khalil
- Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden.
| | - Frauke Ecke
- Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, P.O. Box 7050, 750 07, Uppsala, Sweden
| | - Magnus Evander
- Department of Clinical Microbiology, Virology, Umeå University, 901 85, Umeå, Sweden
| | - Göran Bucht
- Swedish Defense Research Agency, CBRN Defence and Security, Umeå, Sweden
| | - Birger Hörnfeldt
- Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
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36
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Brisse ME, Ly H. Hemorrhagic Fever-Causing Arenaviruses: Lethal Pathogens and Potent Immune Suppressors. Front Immunol 2019; 10:372. [PMID: 30918506 PMCID: PMC6424867 DOI: 10.3389/fimmu.2019.00372] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 02/14/2019] [Indexed: 12/22/2022] Open
Abstract
Hemorrhagic fevers (HF) resulting from pathogenic arenaviral infections have traditionally been neglected as tropical diseases primarily affecting African and South American regions. There are currently no FDA-approved vaccines for arenaviruses, and treatments have been limited to supportive therapy and use of non-specific nucleoside analogs, such as Ribavirin. Outbreaks of arenaviral infections have been limited to certain geographic areas that are endemic but known cases of exportation of arenaviruses from endemic regions and socioeconomic challenges for local control of rodent reservoirs raise serious concerns about the potential for larger outbreaks in the future. This review synthesizes current knowledge about arenaviral evolution, ecology, transmission patterns, life cycle, modulation of host immunity, disease pathogenesis, as well as discusses recent development of preventative and therapeutic pursuits against this group of deadly viral pathogens.
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Affiliation(s)
- Morgan E Brisse
- Biochemistry, Molecular Biology, and Biophysics Graduate Program, University of Minnesota, St. Paul, MN, United States.,Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, United States
| | - Hinh Ly
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, United States
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37
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Mariën J, Borremans B, Kourouma F, Baforday J, Rieger T, Günther S, Magassouba N, Leirs H, Fichet-Calvet E. Evaluation of rodent control to fight Lassa fever based on field data and mathematical modelling. Emerg Microbes Infect 2019; 8:640-649. [PMID: 31007139 PMCID: PMC7011821 DOI: 10.1080/22221751.2019.1605846] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/04/2019] [Indexed: 11/25/2022]
Abstract
The Natal multimammate mouse (Mastomys natalensis) is the reservoir host of Lassa virus, an arenavirus that causes Lassa haemorrhagic fever in humans in West Africa. Because no vaccine exists and therapeutic options are limited, preventing infection through rodent control and human behavioural measures is currently considered to be the only option. In order to assess the efficacy of rodent control, we performed a 4-year field experiment in rural Upper Guinea and developed a mathematical model to simulate different control strategies (annual density control, continuous density control, and rodent vaccination). For the field study, rodenticide baits were placed each year in three rural villages, while three other villages were used as controls. Rodents were trapped before and after every treatment and their antibody status and age were determined. Data from the field study were used to parameterize the mathematical model. In the field study, we found a significant negative effect of rodent control on seroprevalence, but this effect was small especially given the effort. Furthermore, the rodent populations recovered rapidly after rodenticide application, leading us to conclude that an annual control strategy is unlikely to significantly reduce Lassa virus spillover to humans. In agreement with this finding, the mathematical model suggests that the use of continuous control or rodent vaccination is the only strategy that could lead to Lassa virus elimination. These field and model results can serve as a guide for determining how long and frequent rodent control should be done in order to eliminate Lassa virus in rural villages.
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Affiliation(s)
- Joachim Mariën
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | - Benny Borremans
- University of California Los Angeles, Los Angeles, CA, USA
- Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-BIOSTAT), Hasselt University, Hasselt, Belgium
| | - Fodé Kourouma
- Laboratoire des Fièvres Hémorragiques, Nongo, Guinée
| | - Jatta Baforday
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Toni Rieger
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Stephan Günther
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | | | - Herwig Leirs
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
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Widespread arenavirus occurrence and seroprevalence in small mammals, Nigeria. Parasit Vectors 2018; 11:416. [PMID: 30005641 PMCID: PMC6045851 DOI: 10.1186/s13071-018-2991-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 07/03/2018] [Indexed: 11/10/2022] Open
Abstract
Background Lassa fever, killing thousands of people annually, is the most reported viral zoonotic disease in Nigeria. Recently, different rodent species carrying diverse lineages of the Lassa virus (LASV) in addition to a novel Mobala-like genetic sequence were detected within the country. Here, screening 906 small mammal specimens from 11 localities for IgG antibodies and incorporating previous PCR detection data involving the same populations, we further describe arenavirus prevalence across Nigeria in relation to host species and geographical location. Methods Small mammals were trapped during the period 2011–2015 according to geographical location (endemic and non-endemic zones for Lassa fever), season (rainy and dry seasons between 2011 and 2012 for certain localities) and habitat (indoors, peridomestic settings and sylvatic vegetation). Identification of animal specimens from genera such as Mastomys and Mus (Nannomys) was assisted by DNA sequencing. Small mammals were tested for LASV IgG antibody using an indirect immunofluorescence assay (IFA). Results Small mammals were infected in both the endemic and non-endemic zones for Lassa fever, with a wider range of species IgG-positive (n = 8) than those which had been previously detected to be PCR-positive (n = 3). IgG-positive species, according to number of infected individuals, were Mastomys natalensis (n = 40), Mastomys erythroleucus (n = 15), Praomys daltoni (n = 6), Mus baoulei (n = 5), Rattus rattus (n = 2), Crocidura spp. (n = 2), Mus minutoides (n = 1) and Praomys misonnei (n = 1). Multimammate mice (Mastomys natalensis and M. erythroleucus) were the most ubiquitously infected, with animals testing positive by either PCR or IgG in 7 out of the 11 localities sampled. IgG prevalence in M. natalensis ranged from 1% in Abagboro, 17–36 % in Eguare Egoro, Ekpoma and Ngel Nyaki, up to 52 % in Mayo Ranewo. Prevalence according to locality, season and age was not, however, statistically significant for M. natalensis in Eguare Egoro and Ekpoma, localities that were sampled longitudinally. Conclusions Overall, our study demonstrates that arenavirus occurrence is probably more widely distributed geographically and in extent of host taxa than is currently realized. This expanded scope should be taken into consideration in Lassa fever control efforts. Further sampling should also be carried out to isolate and characterize potential arenaviruses present in small mammal populations we found to be seropositive.
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39
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Mariën J, Kourouma F, Magassouba N, Leirs H, Fichet-Calvet E. Movement Patterns of Small Rodents in Lassa Fever-Endemic Villages in Guinea. ECOHEALTH 2018; 15:348-359. [PMID: 29572697 DOI: 10.1007/s10393-018-1331-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 12/25/2017] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
The Natal multimammate mouse (Mastomys natalensis) is the reservoir host of Lassa arenavirus, the etiological agent of Lassa fever in humans. Because there exists no vaccine for human use, rodent control and adjusting human behavior are currently considered to be the only options for Lassa fever control. In order to develop efficient rodent control programs, more information about the host's ecology is needed. In this study, we investigated the spatial behavior of M. natalensis and other small rodents in two capture-mark-recapture and four dyed bait (Rhodamine B) experiments in Lassa fever-endemic villages in Upper Guinea. During the capture-mark-recapture studies, 23% of the recaptured M. natalensis moved between the houses and proximate fields. While M. natalensis was found over the entire study grid (2 ha), other rodent species (Praomys daltoni, Praomys rostratus, Lemniscomys striatus, Mus spp.) were mostly trapped in the surrounding fields. Distances between recapture occasions never exceeded 100 m for all rodent species. During the dyed bait experiments, 11% of M. natalensis and 41% of P. daltoni moved from the fields to houses. We conclude that commensal M. natalensis easily moves between houses and proximate fields in Guinea. We therefore consider occasional domestic rodent elimination to be an unsustainable approach to reduce Lassa virus transmission risk to humans, as M. natalensis is likely to reinvade houses quickly from fields in which rodents are not controlled. A combination of permanent rodent elimination with other control strategies (e.g., make houses rodent proof or attract predators) could be more effective for Lassa fever control, but must be further investigated.
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Affiliation(s)
- Joachim Mariën
- Evolutionary Ecology Group, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium.
| | - Fodé Kourouma
- Laboratoire des Fièvres Hémorragiques, Nongo, Conakry, Guinea
| | | | - Herwig Leirs
- Evolutionary Ecology Group, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium
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Ehlkes L, George M, Samosny G, Burckhardt F, Vogt M, Bent S, Jahn K, Zanger P. Management of a Lassa fever outbreak, Rhineland-Palatinate, Germany, 2016. ACTA ACUST UNITED AC 2018; 22. [PMID: 29019309 PMCID: PMC5709955 DOI: 10.2807/1560-7917.es.2017.22.39.16-00728] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Due to rapid diagnosis and isolation of imported cases, community outbreaks of viral haemorrhagic fevers (VHF) are considered unlikely in industrialised countries. In March 2016, the first documented locally acquired case of Lassa fever (LF) outside Africa occurred, demonstrating the disease’s potential as a cross-border health threat. We describe the management surrounding this case of LF in Rhineland-Palatinate – the German federal state where secondary transmission occurred. Twelve days after having been exposed to the corpse of a LF case imported from Togo, a symptomatic undertaker tested positive for Lassa virus RNA. Potential contacts were traced, categorised based on exposure risk, and monitored. Overall, we identified 21 contact persons with legal residency in Rhineland-Palatinate: seven related to the index case, 13 to the secondary case, and one related to both. The secondary case received treatment and recovered. Five contacts were quarantined and one was temporarily banned from work. No further transmission occurred. Based on the experience gained during the outbreak and a review of national and international guidelines, we conclude that exposure risk attributable to corpses may currently be underestimated, and we present suggestions that may help to improve the anti-epidemic response to imported VHF cases in industrialised countries.
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Affiliation(s)
- Lutz Ehlkes
- These authors contributed equally to this article and share first authorship.,European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.,Postgraduate Training for Applied Epidemiology (PAE), Robert Koch Institute (RKI), Berlin, Germany.,Federal State Agency for Consumer & Health Protection Rhineland-Palatinate, Koblenz, Germany
| | - Maja George
- These authors contributed equally to this article and share first authorship.,Federal State Agency for Consumer & Health Protection Rhineland-Palatinate, Koblenz, Germany
| | | | - Florian Burckhardt
- Federal State Agency for Consumer & Health Protection Rhineland-Palatinate, Koblenz, Germany
| | - Manfred Vogt
- Federal State Agency for Consumer & Health Protection Rhineland-Palatinate, Koblenz, Germany
| | - Stefan Bent
- Federal State Agency for Consumer & Health Protection Rhineland-Palatinate, Koblenz, Germany
| | - Klaus Jahn
- Federal State Ministry for Social Affairs, Employment, Health, and Demographics Rhineland-Palatinate, Mainz, Germany
| | - Philipp Zanger
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospitals, Heidelberg, Germany.,Institute of Public Health, University Hospitals, Heidelberg, Germany.,Federal State Agency for Consumer & Health Protection Rhineland-Palatinate, Koblenz, Germany
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Gibb R, Moses LM, Redding DW, Jones KE. Understanding the cryptic nature of Lassa fever in West Africa. Pathog Glob Health 2017; 111:276-288. [PMID: 28875769 PMCID: PMC5694855 DOI: 10.1080/20477724.2017.1369643] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Lassa fever (LF) is increasingly recognized by global health institutions as an important rodent-borne disease with severe impacts on some of West Africa's poorest communities. However, our knowledge of LF ecology, epidemiology and distribution is limited, which presents barriers to both short-term disease forecasting and prediction of long-term impacts of environmental change on Lassa virus (LASV) zoonotic transmission dynamics. Here, we synthesize current knowledge to show that extrapolations from past research have produced an incomplete picture of the incidence and distribution of LF, with negative consequences for policy planning, medical treatment and management interventions. Although the recent increase in LF case reports is likely due to improved surveillance, recent studies suggest that future socio-ecological changes in West Africa may drive increases in LF burden. Future research should focus on the geographical distribution and disease burden of LF, in order to improve its integration into public policy and disease control strategies.
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Affiliation(s)
- Rory Gibb
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Lina M. Moses
- Department of Global Community Health and Behavioral Sciences, Tulane University, New Orleans, LA, USA
| | - David W. Redding
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Kate E. Jones
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London, UK
- Institute of Zoology, Zoological Society of London, London, UK
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42
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Olayemi A, Obadare A, Oyeyiola A, Fasogbon S, Igbokwe J, Igbahenah F, Ortsega D, Günther S, Verheyen E, Fichet-Calvet E. Small mammal diversity and dynamics within Nigeria, with emphasis on reservoirs of the lassa virus. SYST BIODIVERS 2017. [DOI: 10.1080/14772000.2017.1358220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ayodeji Olayemi
- Natural History Museum, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
| | - Adeoba Obadare
- Natural History Museum, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
| | - Akinlabi Oyeyiola
- Natural History Museum, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
| | | | - Joseph Igbokwe
- Natural History Museum, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
| | - Felix Igbahenah
- Geography Department, Benue State University, Makurdi, Benue State, Nigeria
| | - Daniel Ortsega
- Geography Department, Benue State University, Makurdi, Benue State, Nigeria
| | - Stephan Günther
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Erik Verheyen
- Royal Belgian Institute of Natural Sciences, Brussels, Belgium and University of Antwerp, Antwerp, Belgium
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Mariën J, Borremans B, Gryseels S, Soropogui B, De Bruyn L, Bongo GN, Becker-Ziaja B, de Bellocq JG, Günther S, Magassouba N, Leirs H, Fichet-Calvet E. No measurable adverse effects of Lassa, Morogoro and Gairo arenaviruses on their rodent reservoir host in natural conditions. Parasit Vectors 2017; 10:210. [PMID: 28449693 PMCID: PMC5408478 DOI: 10.1186/s13071-017-2146-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/19/2017] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND In order to optimize net transmission success, parasites are hypothesized to evolve towards causing minimal damage to their reservoir host while obtaining high shedding rates. For many parasite species however this paradigm has not been tested, and conflicting results have been found regarding the effect of arenaviruses on their rodent host species. The rodent Mastomys natalensis is the natural reservoir host of several arenaviruses, including Lassa virus that is known to cause Lassa haemorrhagic fever in humans. Here, we examined the effect of three arenaviruses (Gairo, Morogoro and Lassa virus) on four parameters of wild-caught Mastomys natalensis: body mass, head-body length, sexual maturity and fertility. After correcting for the effect of age, we compared these parameters between arenavirus-positive (arenavirus RNA or antibody) and negative animals using data from different field studies in Guinea (Lassa virus) and Tanzania (Morogoro and Gairo viruses). RESULTS Although the sample sizes of our studies (1297, 749 and 259 animals respectively) were large enough to statistically detect small differences in body conditions, we did not observe any adverse effects of these viruses on Mastomys natalensis. We did find that sexual maturity was significantly positively related with Lassa virus antibody presence until a certain age, and with Gairo virus antibody presence in general. Gairo virus antibody-positive animals were also significantly heavier and larger than antibody-free animals. CONCLUSION Together, these results suggest that the pathogenicity of arenaviruses is not severe in M. natalensis, which is likely to be an adaptation of these viruses to optimize transmission success. They also suggest that sexual behaviour might increase the probability of M. natalensis to become infected with arenaviruses.
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Affiliation(s)
- Joachim Mariën
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | - Benny Borremans
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, USA
| | - Sophie Gryseels
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, USA
| | - Barré Soropogui
- Projet des Fièvre Hémorragiques en Guinée, Hôpital Donka, Conakry, Guinea
| | - Luc De Bruyn
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | - Gédéon Ngiala Bongo
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- Department of Biology, University of Kinshasa, P.O. Box. 190, Kinshasa XI, Democratic Republic of the Congo
| | | | - Joëlle Goüy de Bellocq
- Institute of Vertebrate Biology, Research Facility Studenec, The Czech Academy of Sciences, Brno, Czech Republic
| | - Stephan Günther
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - N’Faly Magassouba
- Projet des Fièvre Hémorragiques en Guinée, Hôpital Donka, Conakry, Guinea
| | - Herwig Leirs
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
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Gryseels S, Baird SJE, Borremans B, Makundi R, Leirs H, Goüy de Bellocq J. When Viruses Don't Go Viral: The Importance of Host Phylogeographic Structure in the Spatial Spread of Arenaviruses. PLoS Pathog 2017; 13:e1006073. [PMID: 28076397 PMCID: PMC5226678 DOI: 10.1371/journal.ppat.1006073] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/17/2016] [Indexed: 01/07/2023] Open
Abstract
Many emerging infections are RNA virus spillovers from animal reservoirs. Reservoir identification is necessary for predicting the geographic extent of infection risk, but rarely are taxonomic levels below the animal species considered as reservoir, and only key circumstances in nature and methodology allow intrinsic virus-host associations to be distinguished from simple geographic (co-)isolation. We sampled and genetically characterized in detail a contact zone of two subtaxa of the rodent Mastomys natalensis in Tanzania. We find two distinct arenaviruses, Gairo and Morogoro virus, each spatially confined to a single M. natalensis subtaxon, only co-occurring at the contact zone’s centre. Inter-subtaxon hybridization at this centre and a continuum of quality habitat for M. natalensis show that both viruses have the ecological opportunity to spread into the other substaxon’s range, but do not, strongly suggesting host-intrinsic barriers. Such barriers could explain why human cases of another M. natalensis-borne arenavirus, Lassa virus, are limited to West Africa. Reservoirs of zoonotic viruses are usually equated with a particular wildlife species. It is rarely assessed whether genetic groups below the species level may instead represent the actual reservoir, though this would have major implications on estimations of the zoonosis’ spatial distribution. Here we investigate whether geographically and genetically distinct subtaxa of the widespread African rodent Mastomys natalensis carry distinct arenaviruses, by sampling in detail across a contact zone of two of these subtaxa. Ongoing hybridization shows that individuals of the subtaxa are in direct physical contact, in principle allowing viral exchange, yet neither of the two arenaviruses -Gairo and Morogoro virus- were found to have crossed the zone. Such intraspecific genetic barriers to arenavirus spatial spread have important implications for our understanding of the related Lassa arenavirus, a pathogen potentially lethal to humans of which Mastomys natalensis is also the main reservoir. Although Lassa virus appears to infect several secondary hosts, its distribution is restricted to West Africa and matches that of another M. natalensis subtaxon. Our data thus indicates that it is because of M. natalensis intraspecific distinctions that the human Lassa fever endemic area has not expanded to the rest of sub-Saharan Africa.
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Affiliation(s)
- Sophie Gryseels
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
- * E-mail:
| | - Stuart J. E. Baird
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Research Facility Studenec, Brno, Czech Republic
| | - Benny Borremans
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Rhodes Makundi
- Pest Management Centre, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Herwig Leirs
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Joëlle Goüy de Bellocq
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Research Facility Studenec, Brno, Czech Republic
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Abstract
INTRODUCTION Lassa virus (LASV), the most prominent human pathogen of the Arenaviridae, is transmitted to humans from infected rodents and can cause Lassa Fever (LF). The sizeable disease burden in West Africa, numerous imported LF cases worldwide, and the possibility that LASV can be used as an agent of biological warfare make a strong case for vaccine development. There are no licensed LASV vaccines and the antiviral treatment is limited to an off-label use of ribavirin that is only partially effective. AREAS COVERED LASV vaccine development is hampered by high cost of biocontainment requirement, the absence of appropriate small animal models, genetic diversity of LASV species, and by high HIV-1 prevalence in LASV endemic areas. Over the past 15 years several vaccine platforms have been developed. Natural history of LASV and pathogenesis of the disease provide strong justification for replication-competent (RC) vaccine as one of the most feasible approaches to control LF. Development of LASV vaccine candidates based on reassortant, recombinant, and alphavirus replicon technologies is covered in this review. Expert commentary: Two lead RC vaccine candidates, reassortant ML29 and recombinant VSV/LASV, have been successfully tested in non-human primates and have been recommended by international vaccine experts for rapid clinical development. Both platforms have powerful molecular tools to further secure safety, improve immunogenicity, and cross-protection. These platforms are well positioned to design multivalent vaccines to protect against all LASV strains citculatrd in West Africa. The regulatory pathway of Candid #1, the first live-attenuated arenaviral vaccine against Argentine hemorrhagic, will be a reasonable guideline for LASV vaccine efficacy trials.
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Affiliation(s)
- Igor S Lukashevich
- a Department of Pharmacology and Toxicology, School of Medicine, and the Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases , University of Louisville , Louisville , KY , USA
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Olayemi A, Cadar D, Magassouba N, Obadare A, Kourouma F, Oyeyiola A, Fasogbon S, Igbokwe J, Rieger T, Bockholt S, Jérôme H, Schmidt-Chanasit J, Garigliany M, Lorenzen S, Igbahenah F, Fichet JN, Ortsega D, Omilabu S, Günther S, Fichet-Calvet E. New Hosts of The Lassa Virus. Sci Rep 2016; 6:25280. [PMID: 27140942 PMCID: PMC4853722 DOI: 10.1038/srep25280] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 04/14/2016] [Indexed: 11/27/2022] Open
Abstract
Lassa virus (LASV) causes a deadly haemorrhagic fever in humans, killing several thousand people in West Africa annually. For 40 years, the Natal multimammate rat, Mastomys natalensis, has been assumed to be the sole host of LASV. We found evidence that LASV is also hosted by other rodent species: the African wood mouse Hylomyscus pamfi in Nigeria, and the Guinea multimammate mouse Mastomys erythroleucus in both Nigeria and Guinea. Virus strains from these animals were isolated in the BSL-4 laboratory and fully sequenced. Phylogenetic analyses of viral genes coding for glycoprotein, nucleoprotein, polymerase and matrix protein show that Lassa strains detected in M. erythroleucus belong to lineages III and IV. The strain from H. pamfi clusters close to lineage I (for S gene) and between II & III (for L gene). Discovery of new rodent hosts has implications for LASV evolution and its spread into new areas within West Africa.
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Affiliation(s)
- Ayodeji Olayemi
- Natural History Museum, Obafemi Awolowo University, HO 220005 Ile-Ife, Nigeria
| | - Daniel Cadar
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, D-20324, Hamburg, Germany
| | - N'Faly Magassouba
- Service des Maladies Infectieuses et Tropicales, Hospital Donka, Conakry, Guinea
| | - Adeoba Obadare
- Natural History Museum, Obafemi Awolowo University, HO 220005 Ile-Ife, Nigeria
| | - Fode Kourouma
- Service des Maladies Infectieuses et Tropicales, Hospital Donka, Conakry, Guinea
| | - Akinlabi Oyeyiola
- Natural History Museum, Obafemi Awolowo University, HO 220005 Ile-Ife, Nigeria
| | | | - Joseph Igbokwe
- Natural History Museum, Obafemi Awolowo University, HO 220005 Ile-Ife, Nigeria
| | - Toni Rieger
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, D-20324, Hamburg, Germany
| | - Sabrina Bockholt
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, D-20324, Hamburg, Germany
| | - Hanna Jérôme
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, D-20324, Hamburg, Germany
| | - Jonas Schmidt-Chanasit
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, D-20324, Hamburg, Germany
| | - Mutien Garigliany
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Stephan Lorenzen
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, D-20324, Hamburg, Germany
| | - Felix Igbahenah
- Department of Geography, Benue State University, Makurdi, Nigeria
| | | | - Daniel Ortsega
- Department of Geography, Benue State University, Makurdi, Nigeria
| | - Sunday Omilabu
- Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Nigeria
| | - Stephan Günther
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, D-20324, Hamburg, Germany
| | - Elisabeth Fichet-Calvet
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, D-20324, Hamburg, Germany
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Fichet-Calvet E, Ölschläger S, Strecker T, Koivogui L, Becker-Ziaja B, Camara AB, Soropogui B, Magassouba N, Günther S. Spatial and temporal evolution of Lassa virus in the natural host population in Upper Guinea. Sci Rep 2016; 6:21977. [PMID: 26911443 PMCID: PMC4766397 DOI: 10.1038/srep21977] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/03/2016] [Indexed: 11/09/2022] Open
Abstract
This study aimed at reconstructing the spatial and temporal evolution of Lassa virus (LASV) in the natural host population. To this end, we generated 132 partial nucleoprotein sequences of LASV from M. natalensis trapped in 12 villages around Faranah, Upper Guinea, over a period of 12 years. This study reveals two main features of LASV evolution in M. natalensis. First, the virus evolves in the reservoir with a molecular clock rate of 9 (7-11) × 10(-4) position(-1) year(-1) implying that contemporary LASV lineages circulate in the Faranah area since less than 100 years. Second, viruses circulating in a specific village are diverse and polyphyletic. We observed, however, there are monophyletic clusters at village and sub-village level at specific points in time. In conclusion, our data indicate that the temporal and spatial pattern of LASV evolution in the natural reservoir is characterized by a combination of stationary circulation within a village and virus movement between villages. The latter feature is relevant for rodent control strategies, as it implies that recurrence of the virus from neighbouring villages may occur in villages where the virus has previously been eradicated.
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Affiliation(s)
| | | | - Thomas Strecker
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Lamine Koivogui
- Projet des Fièvres Hémorragiques en Guinée, Hopital Donka, Conakry, Guinea
| | | | - Amara Bongo Camara
- Projet des Fièvres Hémorragiques en Guinée, Hopital Donka, Conakry, Guinea
| | - Barré Soropogui
- Projet des Fièvres Hémorragiques en Guinée, Hopital Donka, Conakry, Guinea
| | - N'Faly Magassouba
- Projet des Fièvres Hémorragiques en Guinée, Hopital Donka, Conakry, Guinea
| | - Stephan Günther
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Borremans B, Vossen R, Becker-Ziaja B, Gryseels S, Hughes N, Van Gestel M, Van Houtte N, Günther S, Leirs H. Shedding dynamics of Morogoro virus, an African arenavirus closely related to Lassa virus, in its natural reservoir host Mastomys natalensis. Sci Rep 2015; 5:10445. [PMID: 26022445 PMCID: PMC4448520 DOI: 10.1038/srep10445] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/10/2015] [Indexed: 12/15/2022] Open
Abstract
Arenaviruses can cause mild to severe hemorrhagic fevers. Humans mainly get infected through contact with infected rodents or their excretions, yet little is known about transmission dynamics within rodent populations. Morogoro virus (MORV) is an Old World arenavirus closely related to Lassa virus with which it shares the same host species Mastomys natalensis. We injected MORV in its host, and sampled blood and excretions at frequent intervals. Infection in adults was acute; viral RNA disappeared from blood after 18 days post infection (dpi) and from excretions after 39 dpi. Antibodies were present from 7 dpi and never disappeared. Neonatally infected animals acquired a chronic infection with RNA and antibodies in blood for at least 3 months. The quantified excretion and antibody patterns can be used to inform mathematical transmission models, and are essential for understanding and controlling transmission in the natural rodent host populations.
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Affiliation(s)
- Benny Borremans
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | - Raphaël Vossen
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | | | - Sophie Gryseels
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | - Nelika Hughes
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | - Mats Van Gestel
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | | | - Stephan Günther
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Herwig Leirs
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
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