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Soto A, De Coninck L, Devlies AS, Van De Wiele C, Rosales Rosas AL, Wang L, Matthijnssens J, Delang L. Belgian Culex pipiens pipiens are competent vectors for West Nile virus while Culex modestus are competent vectors for Usutu virus. PLoS Negl Trop Dis 2023; 17:e0011649. [PMID: 37729233 PMCID: PMC10545110 DOI: 10.1371/journal.pntd.0011649] [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: 05/26/2023] [Revised: 10/02/2023] [Accepted: 09/07/2023] [Indexed: 09/22/2023] Open
Abstract
BACKGROUND West Nile virus (WNV) and Usutu virus (USUV) are emerging arthropod-borne viruses (arboviruses) in Europe transmitted by Culex mosquitoes. In Belgium, it is currently unknown which Culex species are competent vectors for WNV or USUV and if these mosquitoes carry Wolbachia, an endosymbiotic bacterium that can block arbovirus transmission. The aims of our study were to measure the vector competence of Belgian Culex mosquitoes to WNV and USUV and determine if a naturally acquired Wolbachia infection can influence virus transmission. METHODOLOGY/PRINCIPAL FINDINGS Female Culex mosquitoes were captured from urban and peri-urban sites in Leuven, Belgium and offered an infectious bloodmeal containing WNV lineage 2, USUV European (EU) lineage 3, or USUV African (AF) lineage 3. Blood-fed females were incubated for 14 days at 25°C after which the body, head, and saliva were collected to measure infection, dissemination, and transmission rates as well as transmission efficiency. Mosquito species were identified by qRT-PCR or Sanger sequencing, the presence of infectious virus in mosquitoes was confirmed by plaque assays, and viral genome copies were quantified by qRT-PCR. Culex pipiens pipiens were able to transmit WNV (4.3% transmission efficiency, n = 2/47) but not USUV (EU lineage: n = 0/56; AF lineage: n = 0/37). In contrast, Culex modestus were able to transmit USUV (AF lineage: 20% transmission efficiency, n = 1/5) but not WNV (n = 0/6). We found that the presence or absence of Wolbachia was species-dependent and did not associate with virus transmission. CONCLUSIONS/SIGNIFICANCE This is the first report that Belgian Culex mosquitoes can transmit both WNV and USUV, forewarning the risk of human transmission. More research is needed to understand the potential influence of Wolbachia on arbovirus transmission in Culex modestus mosquitoes.
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Affiliation(s)
- Alina Soto
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium
| | - Lander De Coninck
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Clinical and Epidemiological Virology, KU Leuven, Leuven, Belgium
| | - Ann-Sophie Devlies
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium
| | - Celine Van De Wiele
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium
| | - Ana Lucia Rosales Rosas
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium
| | - Lanjiao Wang
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium
| | - Jelle Matthijnssens
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Clinical and Epidemiological Virology, KU Leuven, Leuven, Belgium
| | - Leen Delang
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium
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Saiz JC, Martín-Acebes MA, Blázquez AB, Escribano-Romero E, Poderoso T, Jiménez de Oya N. Pathogenicity and virulence of West Nile virus revisited eight decades after its first isolation. Virulence 2021; 12:1145-1173. [PMID: 33843445 PMCID: PMC8043182 DOI: 10.1080/21505594.2021.1908740] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
West Nile virus (WNV) is a flavivirus which transmission cycle is maintained between mosquitoes and birds, although it occasionally causes sporadic outbreaks in horses and humans that can result in serious diseases and even death. Since its first isolation in Africa in 1937, WNV had been considered a neglected pathogen until its recent spread throughout Europe and the colonization of America, regions where it continues to cause outbreaks with severe neurological consequences in humans and horses. Although our knowledge about the characteristics and consequences of the virus has increased enormously lately, many questions remain to be resolved. Here, we thoroughly update our knowledge of different aspects of the WNV life cycle: virology and molecular classification, host cell interactions, transmission dynamics, host range, epidemiology and surveillance, immune response, clinical presentations, pathogenesis, diagnosis, prophylaxis (antivirals and vaccines), and prevention, and we highlight those aspects that are still unknown and that undoubtedly require further investigation.
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Affiliation(s)
- Juan-Carlos Saiz
- Department of Biotechnology, National Institute for Agricultural and Food Research and Technology (INIA), Madrid, Spain
| | - Miguel A Martín-Acebes
- Department of Biotechnology, National Institute for Agricultural and Food Research and Technology (INIA), Madrid, Spain
| | - Ana B Blázquez
- Department of Biotechnology, National Institute for Agricultural and Food Research and Technology (INIA), Madrid, Spain
| | - Estela Escribano-Romero
- Department of Biotechnology, National Institute for Agricultural and Food Research and Technology (INIA), Madrid, Spain
| | - Teresa Poderoso
- Molecular Virology Group, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Nereida Jiménez de Oya
- Department of Biotechnology, National Institute for Agricultural and Food Research and Technology (INIA), Madrid, Spain
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Dellicour S, Lequime S, Vrancken B, Gill MS, Bastide P, Gangavarapu K, Matteson NL, Tan Y, du Plessis L, Fisher AA, Nelson MI, Gilbert M, Suchard MA, Andersen KG, Grubaugh ND, Pybus OG, Lemey P. Epidemiological hypothesis testing using a phylogeographic and phylodynamic framework. Nat Commun 2020; 11:5620. [PMID: 33159066 PMCID: PMC7648063 DOI: 10.1038/s41467-020-19122-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 09/30/2020] [Indexed: 01/05/2023] Open
Abstract
Computational analyses of pathogen genomes are increasingly used to unravel the dispersal history and transmission dynamics of epidemics. Here, we show how to go beyond historical reconstructions and use spatially-explicit phylogeographic and phylodynamic approaches to formally test epidemiological hypotheses. We illustrate our approach by focusing on the West Nile virus (WNV) spread in North America that has substantially impacted public, veterinary, and wildlife health. We apply an analytical workflow to a comprehensive WNV genome collection to test the impact of environmental factors on the dispersal of viral lineages and on viral population genetic diversity through time. We find that WNV lineages tend to disperse faster in areas with higher temperatures and we identify temporal variation in temperature as a main predictor of viral genetic diversity through time. By contrasting inference with simulation, we find no evidence for viral lineages to preferentially circulate within the same migratory bird flyway, suggesting a substantial role for non-migratory birds or mosquito dispersal along the longitudinal gradient.
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Affiliation(s)
- Simon Dellicour
- Spatial Epidemiology Lab (SpELL), Université Libre de Bruxelles, CP160/12, 50 Avenue FD Roosevelt, 1050, Bruxelles, Belgium.
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.
| | - Sebastian Lequime
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Bram Vrancken
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Mandev S Gill
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Paul Bastide
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Karthik Gangavarapu
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Nathaniel L Matteson
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Yi Tan
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Infectious Diseases Group, J. Craig Venter Institute, Rockville, MD, USA
| | | | - Alexander A Fisher
- Department of Biomathematics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Martha I Nelson
- Fogarty International Center, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Marius Gilbert
- Spatial Epidemiology Lab (SpELL), Université Libre de Bruxelles, CP160/12, 50 Avenue FD Roosevelt, 1050, Bruxelles, Belgium
| | - Marc A Suchard
- Department of Biomathematics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
- Department of Biostatistics, Fielding School of Public Health, University of California, Los Angeles, CA, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Kristian G Andersen
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
- Scripps Research Translational Institute, La Jolla, CA, 92037, USA
| | - Nathan D Grubaugh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | | | - Philippe Lemey
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
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Comparative Pathology of West Nile Virus in Humans and Non-Human Animals. Pathogens 2020; 9:pathogens9010048. [PMID: 31935992 PMCID: PMC7168622 DOI: 10.3390/pathogens9010048] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/03/2020] [Accepted: 01/03/2020] [Indexed: 12/11/2022] Open
Abstract
West Nile virus (WNV) continues to be a major cause of human arboviral neuroinvasive disease. Susceptible non-human vertebrates are particularly diverse, ranging from commonly affected birds and horses to less commonly affected species such as alligators. This review summarizes the pathology caused by West Nile virus during natural infections of humans and non-human animals. While the most well-known findings in human infection involve the central nervous system, WNV can also cause significant lesions in the heart, kidneys and eyes. Time has also revealed chronic neurologic sequelae related to prior human WNV infection. Similarly, neurologic disease is a prominent manifestation of WNV infection in most non-human non-host animals. However, in some avian species, which serve as the vertebrate host for WNV maintenance in nature, severe systemic disease can occur, with neurologic, cardiac, intestinal and renal injury leading to death. The pathology seen in experimental animal models of West Nile virus infection and knowledge gains on viral pathogenesis derived from these animal models are also briefly discussed. A gap in the current literature exists regarding the relationship between the neurotropic nature of WNV in vertebrates, virus propagation and transmission in nature. This and other knowledge gaps, and future directions for research into WNV pathology, are addressed.
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Duggal NK, Langwig KE, Ebel GD, Brault AC. On the Fly: Interactions Between Birds, Mosquitoes, and Environment That Have Molded West Nile Virus Genomic Structure Over Two Decades. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:1467-1474. [PMID: 31549720 PMCID: PMC7182917 DOI: 10.1093/jme/tjz112] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Indexed: 05/15/2023]
Abstract
West Nile virus (WNV) was first identified in North America almost 20 yr ago. In that time, WNV has crossed the continent and established enzootic transmission cycles, resulting in intermittent outbreaks of human disease that have largely been linked with climatic variables and waning avian seroprevalence. During the transcontinental dissemination of WNV, the original genotype has been displaced by two principal extant genotypes which contain an envelope mutation that has been associated with enhanced vector competence by Culex pipiens L. (Diptera: Culicidae) and Culex tarsalis Coquillett vectors. Analyses of retrospective avian host competence data generated using the founding NY99 genotype strain have demonstrated a steady reduction in viremias of house sparrows over time. Reciprocally, the current genotype strains WN02 and SW03 have demonstrated an inverse correlation between house sparrow viremia magnitude and the time since isolation. These data collectively indicate that WNV has evolved for increased avian viremia while house sparrows have evolved resistance to the virus such that the relative host competence has remained constant. Intrahost analyses of WNV evolution demonstrate that selection pressures are avian species-specific and purifying selection is greater in individual birds compared with individual mosquitoes, suggesting that the avian adaptive and/or innate immune response may impose a selection pressure on WNV. Phylogenomic, experimental evolutionary systems, and models that link viral evolution with climate, host, and vector competence studies will be needed to identify the relative effect of different selective and stochastic mechanisms on viral phenotypes and the capacity of newly evolved WNV genotypes for transmission in continuously changing landscapes.
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Affiliation(s)
- Nisha K Duggal
- Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA
| | - Kate E Langwig
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA
| | - Gregory D Ebel
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO
| | - Aaron C Brault
- Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO
- Corresponding author, e-mail:
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Bialosuknia SM, Tan Y, Zink SD, Koetzner CA, Maffei JG, Halpin RA, Mueller EA, Novotny M, Shilts M, Fedorova NB, Amedeo P, Das SR, Pickett B, Kramer LD, Ciota AT. Evolutionary dynamics and molecular epidemiology of West Nile virus in New York State: 1999-2015. Virus Evol 2019; 5:vez020. [PMID: 31341640 PMCID: PMC6642743 DOI: 10.1093/ve/vez020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Following its introduction into New York State (NYS) in 1999, West Nile virus (WNV; Flavivirus, Flaviviridae) underwent a rapid expansion throughout the USA and into Canada and Latin America. WNV has been characterized as being evolutionarily stable, with weak geographic structure, a dominance of purifying selection and limited adaptive change. We analyzed all available full-genome WNV sequences, focusing on the 543 available sequences from NYS, which included 495 newly sequenced 2000–15 isolates. In addition, we analyzed deep-sequencing data from 317 of these isolates. While our data are generally in agreement with the limited pace of evolutionary change and broad geographic and temporal mixing identified in other studies, we have identified some important exceptions. Most notably, there are 14 codons which demonstrated evidence of positive selection as determined by multiple models, including some positions with evidence of selection in NYS exclusively. Coincident with increased WNV activity, genotypes possessing one or more of these mutations, designated NY01, NY07, and NY10, have increased in prevalence in recent years and displaced historic strains. In addition, we have found a geographical bias with many of these mutations, which suggests selective pressures and adaptations could be regional. Lastly, our deep-sequencing data suggest both increased overall diversity in avian tissue isolates relative to mosquito isolates and multiple non-synonymous minority variants that are both host-specific and retained over time and space. Together, these data provide novel insight into the evolutionary pressures on WNV and the need for continued genetic surveillance and characterization of emergent strains.
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Affiliation(s)
- Sean M Bialosuknia
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
| | - Yi Tan
- Department of Medicine, Vanderbilt University Medical Center, Nashville, 1161 21st Street, Nashville, TN, USA
| | - Steven D Zink
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
| | - Cheri A Koetzner
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
| | - Joseph G Maffei
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
| | - Rebecca A Halpin
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Emmi A Mueller
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Mark Novotny
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Meghan Shilts
- Department of Medicine, Vanderbilt University Medical Center, Nashville, 1161 21st Street, Nashville, TN, USA
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Nadia B Fedorova
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Paolo Amedeo
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Suman R Das
- Department of Medicine, Vanderbilt University Medical Center, Nashville, 1161 21st Street, Nashville, TN, USA
| | - Brett Pickett
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Laura D Kramer
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Rensselear, NY, USA
| | - Alexander T Ciota
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Rensselear, NY, USA
- Corresponding author: E-mail:
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Worwa G, Hutton AA, Brault AC, Reisen WK. Comparative fitness of West Nile virus isolated during California epidemics. PLoS Negl Trop Dis 2019; 13:e0007135. [PMID: 30716113 PMCID: PMC6375641 DOI: 10.1371/journal.pntd.0007135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 02/14/2019] [Accepted: 01/07/2019] [Indexed: 11/30/2022] Open
Abstract
West Nile virus (WNV) has been circulating in California since its first detection in 2003, causing repeated outbreaks affecting public, wildlife and veterinary health. Epidemics of WNV are difficult to predict due to the multitude of factors influencing transmission dynamics among avian and mosquito hosts. Typically, high levels of WNV amplification are required for outbreaks to occur, and therefore associated viral strains may exhibit enhanced virulence and mortality in competent bird species resulting in increased mosquito infection prevalence. In our previous study, most WNV isolates made from California during 2007-08 showed increased fitness when competed in House Finches (HOFI, Haemorhous mexicanus) and Culex tarsalis Coquillett mosquitoes against COAV997-5nt, a genetically marked recombinant virus derived from a 2003 California strain. Herein, we evaluated the competitive fitness of WNV strains isolated during California epidemics in 2004, 2005, 2007, 2011 and 2012 against COAV997-5nt. These outbreak isolates did not produce elevated mortality in HOFIs, but replicated more efficiently than did COAV997-5nt based on quantification of WNV RNA copies in sera, thereby demonstrating increased competitive fitness. Oral co-infections in Cx. tarsalis resulted in similar virus-specific infection and transmission rates, indicating that outbreak isolates did not have a fitness advantage over COAV997-5nt. Collectively, WNV isolates from outbreaks demonstrated relatively greater avian, but not vector, replicative fitness compared to COAV997-5nt, similar to previously characterized non-outbreak isolates of WNV. Our results indicated that ecological rather than viral factors may facilitate WNV amplification to outbreak levels, but monitoring viral phenotypes through competitive fitness studies may provide insight into altered replication and transmission potential among emerging WNV strains.
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Affiliation(s)
- Gabriella Worwa
- Center for Vectorborne Diseases, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Andra A. Hutton
- Center for Vectorborne Diseases, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Aaron C. Brault
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - William K. Reisen
- Center for Vectorborne Diseases, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
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