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Sephton-Clark P, Temfack E, Tenor JL, Toffaletti DL, Loyse A, Molloy SF, Perfect JR, Bicanic T, Harrison TS, Lortholary O, Kouanfack C, Cuomo CA. Genetic diversity and microevolution in clinical Cryptococcus isolates from Cameroon. Med Mycol 2023; 61:myad116. [PMID: 37952096 PMCID: PMC10709296 DOI: 10.1093/mmy/myad116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/03/2023] [Accepted: 11/09/2023] [Indexed: 11/14/2023] Open
Abstract
Cryptococcal meningitis is the second most common cause of death in people living with HIV/AIDS, yet we have a limited understanding of how cryptococcal isolates change over the course of infection. Cryptococcal infections are environmentally acquired, and the genetic diversity of these infecting isolates can also be geographically linked. Here, we employ whole genome sequences for 372 clinical Cryptococcus isolates from 341 patients with HIV-associated cryptococcal meningitis obtained via a large clinical trial, across both Malawi and Cameroon, to enable population genetic comparisons of isolates between countries. We see that isolates from Cameroon are highly clonal, when compared to those from Malawi, with differential rates of disruptive variants in genes with roles in DNA binding and energy use. For a subset of patients (22) from Cameroon, we leverage longitudinal sampling, with samples taken at days 7 and 14 post-enrollment, to interrogate the genetic changes that arise over the course of infection, and the genetic diversity of isolates within patients. We see disruptive variants arising over the course of infection in several genes, including the phagocytosis-regulating transcription factor GAT204. In addition, in 13% of patients sampled longitudinally, we see evidence for mixed infections. This approach identifies geographically linked genetic variation, signatures of microevolution, and evidence for mixed infections across a clinical cohort of patients affected by cryptococcal meningitis in Central Africa.
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Affiliation(s)
- Poppy Sephton-Clark
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Elvis Temfack
- Internal Medicine Unit, Douala General Hospital, Douala, Cameroon
- Institut Pasteur, Molecular Mycology Unit, CNRS UMR 2000, Paris, France
| | - Jennifer L Tenor
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Dena L Toffaletti
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Angela Loyse
- Institute of Infection and Immunity, St George's University of London, London, UK
- Clinical Academic Group in Infection, St George's University Hospital, London, UK
| | - Síle F Molloy
- Institute of Infection and Immunity, St George's University of London, London, UK
| | - John R Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Tihana Bicanic
- Institute of Infection and Immunity, St George's University of London, London, UK
- Clinical Academic Group in Infection, St George's University Hospital, London, UK
| | - Thomas S Harrison
- Institute of Infection and Immunity, St George's University of London, London, UK
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Olivier Lortholary
- Department of Infectious Diseases and Tropical Medicine, Paris Cité University, Necker-Enfants Malades Hospital, AP-HP, IHU Imagine, Paris, France
- Mycology Department and National Reference Center for Invasive Mycoses and Antifungals, Institut Pasteur, Paris, France
| | - Charles Kouanfack
- Department of Public Health, Faculty of Medicine and Pharmaceutical Sciences, University of Dschang, Dschang, Cameroon
- Day Hospital, Hospital Central Yaoundé, Yaoundé, Cameroon
- Research Center for Emerging and Re-emerging Diseases, Cameroon Baptist Convention Health Services (CBCHS), Yaoundé, Cameroon
| | - Christina A Cuomo
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
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Colson P, Bader W, Fantini J, Dudouet P, Levasseur A, Pontarotti P, Devaux C, Raoult D. From viral democratic genomes to viral wild bunch of quasispecies. J Med Virol 2023; 95:e29209. [PMID: 37937701 DOI: 10.1002/jmv.29209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/05/2023] [Accepted: 10/19/2023] [Indexed: 11/09/2023]
Abstract
The tremendous majority of RNA genomes from pathogenic viruses analyzed and deposited in databases are consensus or "democratic" genomes. They represent the genomes most frequently found in the clinical samples of patients but do not account for the huge genetic diversity of coexisting genomes, which is better described as quasispecies. A viral quasispecies is defined as the dynamic distribution of nonidentical but closely related mutants, variants, recombinant, or reassortant viral genomes. Viral quasispecies have collective behavior and dynamics and are the subject of internal interactions that comprise interference, complementation, or cooperation. In the setting of SARS-CoV-2 infection, intrahost SARS-CoV-2 genetic diversity was recently notably reported for immunocompromised, chronically infected patients, for patients treated with monoclonal antibodies targeting the viral spike protein, and for different body compartments of a single patient. A question that deserves attention is whether such diversity is generated postinfection from a clonal genome in response to selection pressure or is already present at the time of infection as a quasispecies. In the present review, we summarize the data supporting that hosts are infected by a "wild bunch" of viruses rather than by multiple virions sharing the same genome. Each virion in the "wild bunch" may have different virulence and tissue tropisms. As the number of viruses replicated during host infections is huge, a viral quasispecies at any time of infection is wide and is also influenced by host-specific selection pressure after infection, which accounts for the difficulty in deciphering and predicting the appearance of more fit variants and the evolution of epidemics of novel RNA viruses.
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Affiliation(s)
- Philippe Colson
- IHU Méditerranée Infection, Marseille, France
- Aix-Marseille Université., Institut de Recherche pour le Développement (IRD), Microbes Evolution Phylogeny and Infections (MEPHI), Marseille, France
- Assistance Publique-Hôpitaux de Marseille (AP-HM), Marseille, France
| | - Wahiba Bader
- IHU Méditerranée Infection, Marseille, France
- Aix-Marseille Université., Institut de Recherche pour le Développement (IRD), Microbes Evolution Phylogeny and Infections (MEPHI), Marseille, France
| | - Jacques Fantini
- INSERM UMR_S 1072, Aix-Marseille Université, Marseille, France
| | - Pierre Dudouet
- IHU Méditerranée Infection, Marseille, France
- Aix-Marseille Université., Institut de Recherche pour le Développement (IRD), Microbes Evolution Phylogeny and Infections (MEPHI), Marseille, France
| | - Anthony Levasseur
- IHU Méditerranée Infection, Marseille, France
- Aix-Marseille Université., Institut de Recherche pour le Développement (IRD), Microbes Evolution Phylogeny and Infections (MEPHI), Marseille, France
| | - Pierre Pontarotti
- IHU Méditerranée Infection, Marseille, France
- Department of Biological Sciences, Centre National de la Recherche 16 Scientifique (CNRS)-SNC5039, Marseille, France
| | - Christian Devaux
- IHU Méditerranée Infection, Marseille, France
- Department of Biological Sciences, Centre National de la Recherche 16 Scientifique (CNRS)-SNC5039, Marseille, France
| | - Didier Raoult
- IHU Méditerranée Infection, Marseille, France
- Aix-Marseille Université., Institut de Recherche pour le Développement (IRD), Microbes Evolution Phylogeny and Infections (MEPHI), Marseille, France
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Torres MC, Di Maio F, Brown D, Spyer M, Nastouli E, Brasil P, Bispo de Filippis AM. In Depth Viral Diversity Analysis in Atypical Neurological and Neonatal Chikungunya Infections in Rio de Janeiro, Brazil. Viruses 2022; 14:2006. [PMID: 36146812 DOI: 10.3390/v14092006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/03/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022] Open
Abstract
Chikungunya virus (CHIKV) is an arthropod-borne virus (arbovirus) transmitted by Aedes mosquitoes. The human infection usually manifests as a febrile and incapacitating arthritogenic illness, self-limiting and non-lethal. However, since 2013, CHIKV spreading through the tropics and to the Americas was accompanied by an increasing number of cases of atypical disease presentation, namely severe neuropathies and neonatal infection due to intrapartum vertical transmission. The pathophysiological mechanisms underlying these conditions have not been fully elucidated. However, arbovirus intrahost genetic diversity is thought to be linked to viral pathogenesis. To determine whether particular viral variants could be somehow associated, we analyzed the intrahost genetic diversity of CHIKV in three infected patients with neurological manifestations and three mothers infected during the intrapartum period, as well as their babies following vertical transmission. No statistically supported differences were observed for the genetic variability (nucleotide substitutions/gene length) along the genome between the groups. However, the newborn and cerebrospinal fluid samples (corresponding to virus passed through the placenta and/or the blood–brain barrier (BBB)) presented a different composition of their intrahost mutant ensembles compared to maternal or patient serum samples, even when concurrent. This finding could be consistent with the unidirectional virus transmission through these barriers, and the effect of selective bottlenecks during the transmission event. In addition, a higher proportion of defective variants (insertions/deletions and stop codons) was detected in the CSF and maternal samples and those were mainly distributed within the viral non-structural genes. Since defective viral genomes in RNA viruses are known to contribute to the outcome of acute viral infections and influence disease severity, their role in these atypical cases should be further investigated. Finally, with the in silico approach adopted, we detected no relevant non-conservative mutational pattern that could provide any hint of the pathophysiological mechanisms underlying these atypical cases. The present analysis represents a unique contribution to our understanding of the transmission events in these cases and generates hypotheses regarding underlying mechanisms, that can be explored further.
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Levade I, Khan AI, Chowdhury F, Calderwood SB, Ryan ET, Harris JB, LaRocque RC, Bhuiyan TR, Qadri F, Weil AA, Shapiro BJ. A Combination of Metagenomic and Cultivation Approaches Reveals Hypermutator Phenotypes within Vibrio cholerae-Infected Patients. mSystems 2021; 6:e0088921. [PMID: 34427503 DOI: 10.1128/mSystems.00889-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio cholerae can cause a range of symptoms, from severe diarrhea to asymptomatic infection. Previous studies using whole-genome sequencing (WGS) of multiple bacterial isolates per patient showed that V. cholerae can evolve modest genetic diversity during symptomatic infection. To further explore the extent of V. cholerae within-host diversity, we applied culture-based WGS and metagenomics to a cohort of both symptomatic and asymptomatic cholera patients from Bangladesh. While metagenomics allowed us to detect more mutations in symptomatic patients, WGS of cultured isolates was necessary to detect V. cholerae diversity in asymptomatic carriers, likely due to their low V. cholerae load. Using both metagenomics and isolate WGS, we report three lines of evidence that V. cholerae hypermutators evolve within patients. First, we identified nonsynonymous mutations in V. cholerae DNA repair genes in 5 out of 11 patient metagenomes sequenced with sufficient coverage of the V. cholerae genome and in 1 of 3 patients with isolate genomes sequenced. Second, these mutations in DNA repair genes tended to be accompanied by an excess of intrahost single nucleotide variants (iSNVs). Third, these iSNVs were enriched in transversion mutations, a known hallmark of hypermutator phenotypes. While hypermutators appeared to generate mostly selectively neutral mutations, nonmutators showed signs of convergent mutation across multiple patients, suggesting V. cholerae adaptation within hosts. Our results highlight the power and limitations of metagenomics combined with isolate sequencing to characterize within-patient diversity in acute V. cholerae infections, while providing evidence for hypermutator phenotypes within cholera patients. IMPORTANCE Pathogen evolution within patients can impact phenotypes such as drug resistance and virulence, potentially affecting clinical outcomes. V. cholerae infection can result in life-threatening diarrheal disease or asymptomatic infection. Here, we describe whole-genome sequencing of V. cholerae isolates and culture-free metagenomic sequencing from stool of symptomatic cholera patients and asymptomatic carriers. Despite the typically short duration of cholera, we found evidence for adaptive mutations in the V. cholerae genome that occur independently and repeatedly within multiple symptomatic patients. We also identified V. cholerae hypermutator phenotypes within several patients, which appear to generate mainly neutral or deleterious mutations. Our work sets the stage for future studies of the role of hypermutators and within-patient evolution in explaining the variation from asymptomatic carriage to symptomatic cholera.
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Torres MC, Lima de Mendonça MC, Damasceno dos Santos Rodrigues C, Fonseca V, Ribeiro MS, Brandão AP, Venâncio da Cunha R, Dias AI, Santos Vilas Boas L, Felix AC, Alves Pereira M, de Oliveira Pinto LM, Sakuntabhai A, Bispo de Filippis AM. Dengue Virus Serotype 2 Intrahost Diversity in Patients with Different Clinical Outcomes. Viruses 2021; 13:v13020349. [PMID: 33672226 PMCID: PMC7926750 DOI: 10.3390/v13020349] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 02/07/2021] [Accepted: 02/13/2021] [Indexed: 02/07/2023] Open
Abstract
Intrahost genetic diversity is thought to facilitate arbovirus adaptation to changing environments and hosts, and it might also be linked to viral pathogenesis. Dengue virus serotype 2 (DENV-2) has circulated in Brazil since 1990 and is associated with severe disease and explosive outbreaks. Intending to shed light on the viral determinants for severe dengue pathogenesis, we sought to analyze the DENV-2 intrahost genetic diversity in 68 patient cases clinically classified as dengue fever (n = 31), dengue with warning signs (n = 19), and severe dengue (n = 18). Unlike previous DENV intrahost diversity studies whose approaches employed PCR, here we performed viral whole-genome deep sequencing from clinical samples with an amplicon-free approach, representing the real intrahost diversity scenario. Striking differences were detected in the viral population structure between the three clinical categories, which appear to be driven mainly by different infection times and selection pressures, rather than being linked with the clinical outcome itself. Diversity in the NS2B gene, however, showed to be constrained, irrespective of clinical outcome and infection time. Finally, 385 non-synonymous intrahost single-nucleotide variants located along the viral polyprotein, plus variants located in the untranslated regions, were consistently identified among the samples. Of them, 124 were exclusively or highly detected among cases with warning signs and among severe cases. However, there was no variant that by itself appeared to characterize the cases of greater severity, either due to its low intrahost frequency or the conservative effect on amino acid substitution. Although further studies are necessary to determine their real effect on viral proteins, this heightens the possibility of epistatic interactions. The present analysis represents an initial effort to correlate DENV-2 genetic diversity to its pathogenic potential and thus contribute to understanding the virus’s dynamics within its human host.
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Affiliation(s)
- Maria Celeste Torres
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fiocruz, 21040-360 Rio de Janeiro, Brazil; (M.C.L.d.M.); (C.D.d.S.R.); (A.M.B.d.F.)
- Correspondence:
| | - Marcos Cesar Lima de Mendonça
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fiocruz, 21040-360 Rio de Janeiro, Brazil; (M.C.L.d.M.); (C.D.d.S.R.); (A.M.B.d.F.)
| | | | - Vagner Fonseca
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), School of Laboratory Medicine and Medical Sciences, Nelson R Mandela School of Medicine, College of Health Sciences, University of KwaZulu-Natal, 4041 Durban, South Africa;
- Laboratório de Genética Celular e Molecular, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Brazil
- Coordenação Geral dos Laboratórios de Saúde Pública/Secretaria de Vigilância em Saúde, Ministério da Saúde, (CGLAB/SVS-MS) Brasília, 70719-040 Distrito Federal, Brazil
| | - Mario Sergio Ribeiro
- Superintendência Secretaria de Vigilância em Saúde do Estado do Rio de Janeiro, 20031-142 Rio de Janeiro, Brazil;
| | - Ana Paula Brandão
- Laboratório Central Noel Nutels/LACEN, 20231-092 Rio de Janeiro, Brazil;
| | - Rivaldo Venâncio da Cunha
- Coordenação de Vigilância em Saúde e Laboratórios de Referência da Fundação Oswaldo Cruz, FIOCRUZ, 21040-360 Rio de Janeiro, Brazil;
| | - Ana Isabel Dias
- Instituto de Medicina Tropical, Faculdade de Medicina, Universidade de São Paulo, 05403-000 São Paulo, Brazil; (A.I.D.); (L.S.V.B.); (A.C.F.)
| | - Lucy Santos Vilas Boas
- Instituto de Medicina Tropical, Faculdade de Medicina, Universidade de São Paulo, 05403-000 São Paulo, Brazil; (A.I.D.); (L.S.V.B.); (A.C.F.)
| | - Alvina Clara Felix
- Instituto de Medicina Tropical, Faculdade de Medicina, Universidade de São Paulo, 05403-000 São Paulo, Brazil; (A.I.D.); (L.S.V.B.); (A.C.F.)
| | | | | | - Anavaj Sakuntabhai
- Functional Genetics of Infectious Diseases, Department of Global Health, Institut Pasteur, 75015 Paris, France;
| | - Ana Maria Bispo de Filippis
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fiocruz, 21040-360 Rio de Janeiro, Brazil; (M.C.L.d.M.); (C.D.d.S.R.); (A.M.B.d.F.)
| | - on behalf of ZikAction Consortium
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fiocruz, 21040-360 Rio de Janeiro, Brazil; (M.C.L.d.M.); (C.D.d.S.R.); (A.M.B.d.F.)
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Valesano AL, Rumfelt KE, Dimcheff DE, Blair CN, Fitzsimmons WJ, Petrie JG, Martin ET, Lauring AS. Temporal dynamics of SARS-CoV-2 mutation accumulation within and across infected hosts. bioRxiv 2021:2021.01.19.427330. [PMID: 33501443 PMCID: PMC7836113 DOI: 10.1101/2021.01.19.427330] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Analysis of SARS-CoV-2 genetic diversity within infected hosts can provide insight into the generation and spread of new viral variants and may enable high resolution inference of transmission chains. However, little is known about temporal aspects of SARS-CoV-2 intrahost diversity and the extent to which shared diversity reflects convergent evolution as opposed to transmission linkage. Here we use high depth of coverage sequencing to identify within-host genetic variants in 325 specimens from hospitalized COVID-19 patients and infected employees at a single medical center. We validated our variant calling by sequencing defined RNA mixtures and identified a viral load threshold that minimizes false positives. By leveraging clinical metadata, we found that intrahost diversity is low and does not vary by time from symptom onset. This suggests that variants will only rarely rise to appreciable frequency prior to transmission. Although there was generally little shared variation across the sequenced cohort, we identified intrahost variants shared across individuals who were unlikely to be related by transmission. These variants did not precede a rise in frequency in global consensus genomes, suggesting that intrahost variants may have limited utility for predicting future lineages. These results provide important context for sequence-based inference in SARS-CoV-2 evolution and epidemiology.
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Affiliation(s)
- Andrew L. Valesano
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Kalee E. Rumfelt
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Derek E. Dimcheff
- Division of Hospital Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Christopher N. Blair
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - William J. Fitzsimmons
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Joshua G. Petrie
- Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA
| | - Emily T. Martin
- Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA
| | - Adam S. Lauring
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
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7
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Renzette N, Pfeifer SP, Matuszewski S, Kowalik TF, Jensen JD. On the Analysis of Intrahost and Interhost Viral Populations: Human Cytomegalovirus as a Case Study of Pitfalls and Expectations. J Virol 2017; 91:e01976-16. [PMID: 27974561 DOI: 10.1128/JVI.01976-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/01/2016] [Indexed: 12/27/2022] Open
Abstract
Intrahost and interhost assessments of viral diversity are often treated as measures of separate and distinct evolutionary processes, with numerous investigations reporting seemingly incompatible results between the two. For example, in human cytomegalovirus, the nucleotide diversity estimates are 10-fold higher for interhost data, while the number of segregating (i.e., polymorphic) sites is 6-fold lower. These results have been interpreted as demonstrating that sampled intrahost variants are strongly deleterious. In reality, however, these observations are fully consistent with standard population genetic expectations. Here, we analyze published intra- and interhost data sets within this framework, utilizing statistical inference tools to quantify the fitness effects of segregating mutations. Further, we utilize population level simulations to clarify expectations under common evolutionary models. Contrary to common claims in the literature, these results suggest that most observed polymorphisms are likely nearly neutral with regard to fitness and that standard population genetic models in fact well predict observed levels of both intra- and interhost variability. IMPORTANCE With the increasing number of evolutionary virology studies examining both intrahost and interhost patterns of genomic variation, a number of seemingly incompatible results have emerged, revolving around the far greater level of observed intrahost than interhost variation. This has led many authors to suggest that the great majority of sampled within-host polymorphisms are strongly deleterious. Here, we demonstrate that there is in fact no incompatibility of these results and, indeed, that the vast majority of sampled within-host variation is likely neutral. These results thus represent a major shift in the current view of observed viral variation.
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Abstract
RNA virus exploration within the field of medical virology has greatly benefited from technological developments in genomics, deepening our understanding of viral dynamics and emergence. Large-scale first-generation technology sequencing projects have expedited molecular epidemiology studies at an unprecedented scale for two pathogenic RNA viruses chosen as models: influenza A virus and dengue. Next-generation sequencing approaches are now leading to a more in-depth analysis of virus genetic diversity, which is greater for RNA than DNA viruses because of high replication rates and the absence of proofreading activity of the RNA-dependent RNA polymerase. In the field of virus discovery, technological advancements and metagenomic approaches are expanding the catalogs of novel viruses by facilitating our probing into the RNA virus world.
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Affiliation(s)
- Vivien G Dugan
- Viral Genomics, J Craig Venter Institute, Rockville, MD, USA
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Ciota AT, Koch EM, Willsey GG, Davis LJ, Jerzak GVS, Ehrbar DJ, Wilke CO, Kramer LD. Temporal and spatial alterations in mutant swarm size of St. Louis encephalitis virus in mosquito hosts. Infect Genet Evol 2011; 11:460-8. [PMID: 21215334 PMCID: PMC3251332 DOI: 10.1016/j.meegid.2010.12.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 12/14/2010] [Accepted: 12/15/2010] [Indexed: 11/21/2022]
Abstract
St. Louis encephalitis virus (SLEV; Flaviviridae; Flavivirus) is a member of the Japanese encephalitis serocomplex and a close relative of West Nile virus (WNV). Although SLEV remains endemic to the US, both levels of activity and geographical dispersal are relatively constrained when compared to the widespread distribution of WNV. In recent years, WNV appears to have displaced SLEV in California, yet both viruses currently coexist in Texas and several other states. It has become clear that viral swarm characterization is required if we are to fully evaluate the relationship between viral genomes, viral evolution, and epidemiology. Mutant swarm size and composition may be particularly important for arboviruses, which require replication not only in diverse tissues but also divergent hosts. In order to evaluate temporal, spatial, and host-specific patterns in the SLEV mutant swarm, we determined the size, composition, and phylogeny of the intrahost swarm within primary mosquito isolates from both Texas and California. Results indicate a general trend of decreasing intrahost diversity over time in both locations, with recent isolates being highly genetically homogeneous. Additionally, phylogenic analyses provide detailed information on the relatedness of minority variants both within and among strains and demonstrate how both geographic isolation and seasonal maintenance have shaped the viral swarm. Overall, these data generally provide insight into how time, space, and unique transmission cycles influence the SLEV mutant swarm and how understanding these processes can ultimately lead to a better understanding of arbovirus evolution and epidemiology.
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Affiliation(s)
- Alexander T. Ciota
- Arbovirus Laboratory, Wadsworth Center, New York State Dept. of Health, Slingerlands, NY, United States
- State University of New York, Department of Biological Sciences, Albany, NY, United States
| | - Evan M. Koch
- Center for Computational Biology and Bioinformatics, Section of Integrative Biology, and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Graham G. Willsey
- Arbovirus Laboratory, Wadsworth Center, New York State Dept. of Health, Slingerlands, NY, United States
| | - Lauren J. Davis
- Arbovirus Laboratory, Wadsworth Center, New York State Dept. of Health, Slingerlands, NY, United States
| | - Greta V. S. Jerzak
- Arbovirus Laboratory, Wadsworth Center, New York State Dept. of Health, Slingerlands, NY, United States
| | - Dylan J. Ehrbar
- Arbovirus Laboratory, Wadsworth Center, New York State Dept. of Health, Slingerlands, NY, United States
| | - Claus O. Wilke
- Center for Computational Biology and Bioinformatics, Section of Integrative Biology, and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Laura D. Kramer
- Arbovirus Laboratory, Wadsworth Center, New York State Dept. of Health, Slingerlands, NY, United States
- School of Public Health, State University of New York at Albany, Albany, NY, United States
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