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Hung TH, Chen VCH, Yang YH, Tsai CS, Lu ML, McIntyre RS, Lee Y, Huang KY. Association between enterovirus infection and speech and language impairments: A nationwide population-based study. RESEARCH IN DEVELOPMENTAL DISABILITIES 2018; 77:76-86. [PMID: 29705533 DOI: 10.1016/j.ridd.2018.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 04/16/2018] [Accepted: 04/19/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND AND AIMS Delay and impairment in Speech and language are common developmental problems in younger populations. Hitherto, there has been minimal study of the association between common childhood infections (e.g. enterovirus [EV]) and speech and language. The impetus for evaluating this association is provided by evidence linking inflammation to neurodevelopmental disorders. Herein we sought to determine whether an association exists between EV infection and subsequent diagnoses of speech and language impairments in a nationwide population-based sample in Taiwan. METHODS Our study acquired data from the Taiwan National Health Insurance Research Database. The sample was comprised of individuals under 18 years of age with newly diagnosed EV infection during the period from January 1998 to December 2011. 39669 eligible cases were compared to matched controls and assessed during the study period for incident cases of speech and language impairments. Cox regression analyses were applied, adjusting for sex, age and other physical and mental problems. RESULTS In the fully adjusted Cox regression model for hazard ratios, EV infection as positively associated with speech and language impairments (HR = 1.14, 95% CI: 1.06-1.22) after adjusting for age, sex and other confounds. Compared to the control group, the hazard ratio for speech and language impairments was 1.12 (95% CI: 1.03-1.21) amongst the group of EV infection without hospitalization, and 1.26 (95% CI: 1.10-1.45) amongst the group of EV infection with hospitalization. CONCLUSIONS EV infection is temporally associated with incident speech and language impairments. Our findings herein provide rationale for educating families that EV infection may be associated with subsequent speech and language problems in susceptible individuals and that monitoring for such a presentation would be warranted. WHAT THIS PAPER ADDS?: Speech and language impairments associated with central nervous system infections have been reported in the literature. EV are medically important human pathogens and associated with select neuropsychiatric diseases. Notwithstanding, relatively few reports have mentioned the effects of EV infection on speech and language problems. Our study used a nationwide longitudinal dataset and identified that children with EV infection have a greater risk for speech and language impairments as compared with control group. Infected children combined other comorbidities or risk factors might have greater possibility to develop speech problems. Clinicians should be vigilant for the onset of language developmental abnormalities of preschool children with EV infection.
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Affiliation(s)
- Tai-Hsin Hung
- Department of Psychiatry, Chang Gung Memorial Hospital and University, Chiayi, Taiwan; School of Medicine, Chang Gung University, Taoyuan, Taiwan; Chang Gung Institute of Technology, Taoyuan, Taiwan
| | - Vincent Chin-Hung Chen
- Department of Psychiatry, Chang Gung Memorial Hospital and University, Chiayi, Taiwan; School of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yao-Hsu Yang
- Department for Traditional Chinese Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan; Center of Excellence for Chang Gung Research Datalink, Chang Gung Memorial Hospital, Chiayi, Taiwan; Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University College of Public Health, Taipei, Taiwan
| | - Ching-Shu Tsai
- Department of Psychiatry, Chang Gung Memorial Hospital and University, Chiayi, Taiwan; School of Medicine, Chang Gung University, Taoyuan, Taiwan; Chang Gung Institute of Technology, Taoyuan, Taiwan
| | - Mong-Liang Lu
- Department of Psychiatry, Wan-Fang Hospital & School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Roger S McIntyre
- Department of Psychiatry, University of Toronto, Toronto, Canada; Mood Disorders Psychopharmacology Unit, University Health Network, University of Toronto, Toronto, Canada
| | - Yena Lee
- Mood Disorders Psychopharmacology Unit, University Health Network, University of Toronto, Toronto, Canada
| | - Kuo-You Huang
- Department of Speech Language Pathology and Audiology, Chung Shan Medical University and Hospital, Taichung, Taiwan.
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Increased Risk of Tics in Children Infected with Enterovirus: A Nationwide Population-Based Study. J Dev Behav Pediatr 2017; 38:276-282. [PMID: 28353494 DOI: 10.1097/dbp.0000000000000435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Both tics and enterovirus (EV) infections are common in children. The association between EV infections and tics has been seldom evaluated. The aim of this study was to evaluate the risk of diagnosed tics after EV infections in children. METHODS A nationwide retrospective cohort study was conducted to determine the risk of tics after EV infections by analyzing data from the National Health Insurance Research Database in Taiwan. Children aged < 18 years with EV infection during 2000 to 2007 were enrolled. For comparison, non-EV-infected children were randomly selected and matched with EV-infected children at a 1:1 ratio according to sex, age, urbanization level, parental occupation, and the year of EV infection. All patients were followed up until the diagnosis of tics, death, loss to follow-up, withdrawal from the insurance system, or December 31, 2008. RESULTS A total of 282,321 EV-infected and 282,317 non-EV-infected children were included in this study. The mean age was 2.39 years in both cohorts. The overall incidences of tics were 9.12 and 6.21 per 10,000 person-years in the EV-infected and non-EV-infected cohorts, respectively. Children with EV infection were significantly associated with an increased risk of tics compared with those without EV infection (adjusted hazard ratio, 1.38; 95% confidence interval, 1.27-1.5). Multivariable analyses showed that boys, children living in urbanized areas, children whose parents had white-collar jobs, and children with allergic rhinitis or bronchial asthma exhibited a significantly increased risk of tics. CONCLUSION This study revealed an increased risk of tics after EV infection in children.
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Tsai CS, Yang YH, Huang KY, Lee Y, McIntyre RS, Chen VCH. Association of Tic Disorders and Enterovirus Infection: A Nationwide Population-Based Study. Medicine (Baltimore) 2016; 95:e3347. [PMID: 27082591 PMCID: PMC4839835 DOI: 10.1097/md.0000000000003347] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
There has been growing interest in the association between infectious disease and mental disorders, but an association between enterovirus (EV) infection and tic disorders has not been sufficiently explored. Herein, we aim to investigate the association between EV infection and incidence of tic disorders in a nationwide population-based sample using Taiwan's National Health Insurance Research Database. We identified individuals aged ≤18 years prior to 2005 with an inpatient diagnosis of EV infection and/or history of EV infection. Tic disorder was operationalized using International Classification of Disease, Revision 9, Clinical Modification (ICD-9-CM) codes 307.20-307.23. A total of 47,998 individuals with history of EV infection were compared to 47,998 sex-, age-, and urbanization-matched controls on incidence of tic disorders. The mean ± standard deviation follow-up period for all subjects was 9.7 ± 3.6 years; the mean latency period between initial EV infection and incident diagnosis of tic disorder diagnosis was 5.4 ± 2.8 years. EV infection was significantly associated with greater incidence of tic disorders (hazard ratio [HR] = 1.24, 95% CI: 1.07-1.45). When subgrouped on the basis of central nervous system (CNS) involvement, EV infection with CNS involvement was not significantly associated with greater incidence of tic disorders when compared to controls (HR = 1.25, 95% CI: 0.64-2.43); EV infection without CNS involvement was significantly associated greater incidence of tic disorders when compared to controls (HR = 1.24, 95% CI: 1.07-1.45). In addition, hospitalization for an EV infection did not increase the hazard for greater incidence of tic disorders (HR = 1.32, 95% CI: 1.04-1.67 with hospitalization and 1.22, 95% CI: 1.04-1.44 without hospitalization). EV infection is temporally associated with incidence of tic disorders. Our observations add to the growing body of literature implicating immune-inflammatory system in the pathoetiology of brain disorders in a subpopulation of individuals and serve as a clarion call for surveillance of symptoms suggestive of tic disorders in individuals with history of EV infection.
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Affiliation(s)
- Ching-Shu Tsai
- From the Department of Psychiatry, Chang Gung Memorial Hospital and University, Chiayi (C-ST, VC-HC); Graduate Institute of Clinical Medical Sciences, Chang Gung University (C-ST, VC-HC); Chang Gung Institute of Technology, Taoyuan (C-ST); Department for Traditional Chinese Medicine (Y-HY); Center of Excellence for Chang Gung Research Datalink, Chang Gung Memorial Hospital, Chiayi (Y-HY); Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University College of Public Health, Taipei (Y-HY), Department of Speech, Language Pathology and Audiology, Chung Shan Medical University, Taichung, Taiwan (K-YH); and Department of Psychiatry, University of Toronto, Mood Disorders Psychopharmacology Unit, University Health Network (YL, RSM), Toronto, Ontario, Canada
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Chu PY, Tyan YC, Chen YS, Chen HL, Lu PL, Chen YH, Chen BC, Huang TS, Wang CF, Su HJ, Shi YY, Sanno-Duanda B, Lin KH, Motomura K. Transmission and Demographic Dynamics of Coxsackievirus B1. PLoS One 2015; 10:e0129272. [PMID: 26053872 PMCID: PMC4460132 DOI: 10.1371/journal.pone.0129272] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 05/06/2015] [Indexed: 11/19/2022] Open
Abstract
The infectious activity of coxsackievirus B1 (CV-B1) in Taiwan was high from 2008 to 2010, following an alarming increase in severe neonate disease in the United States (US). To examine the relationship between CV-B1 strains isolated in Taiwan and those from other parts of the world, we performed a phylodynamic study using VP1 and partial 3Dpol (414 nt) sequences from 22 strains of CV-B1 isolated in Taiwan (1989-2010) and compared them to sequences from strains isolated worldwide. Phylogenetic trees were constructed by neighbor-joining, maximum likelihood, and Bayesian Monte Carlo Markov Chain methods. Four genotypes (GI-IV) in the VP1 region of CV-B1 and three genotypes (GA-C) in the 3Dpol region of enterovirus B were identified and had high support values. The phylogenetic analysis indicates that the GI and GIII strains in VP1 were geographically distributed in Taiwan (1993-1994) and in India (2007-2009). On the other hand, the GII and GIV strains appear to have a wider spatiotemporal distribution and ladder-like topology A stair-like phylogeny was observed in the VP1 region indicating that the phylogeny of the virus may be affected by different selection pressures in the specified regions. Further, most of the GI and GII strains in the VP1 tree were clustered together in GA in the 3D tree, while the GIV strains diverged into GB and GC. Taken together, these data provide important insights into the population dynamics of CV-B1 and indicate that incongruencies in specific gene regions may contribute to spatiotemporal patterns of epidemicity for this virus.
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Affiliation(s)
- Pei-Yu Chu
- Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC
- Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, ROC
- * E-mail: (PYC); (KM)
| | - Yu-Chang Tyan
- Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Translational Research Center, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
- National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, Kaohsiung 804, Taiwan
- Institute of Medical Science and Technology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Yao-Shen Chen
- Division of Infectious Diseases, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC
- Division of Microbiology, Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC
- Department of Internal Medicine, National Yang-Ming Medical University, Taipei, Taiwan, ROC
| | - Hsiu-Lin Chen
- Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- Department of Respiratory Therapy, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Po-Liang Lu
- Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, ROC
- Department of Laboratory Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan
| | - Yu-Hsien Chen
- Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC
| | - Bao-Chen Chen
- Division of Microbiology, Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC
| | - Tsi-Shu Huang
- Division of Microbiology, Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC
| | - Chu-Feng Wang
- Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, ROC
| | - Hui-Ju Su
- Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, ROC
| | - Yong-Ying Shi
- Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC
| | - Bintou Sanno-Duanda
- Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC
- Edward Francis Small Teaching Hospital, Banjul, Gambia
| | - Kuei-Hsiang Lin
- Department of Laboratory Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan
| | - Kazushi Motomura
- Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
- Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Research Institute of Microbial Diseases, Osaka University, Nonthaburi, Thailand
- * E-mail: (PYC); (KM)
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Bekdas M, Tufan AE, Hakyemez IN, Tas T, Altunhan H, Demircioglu F, Kismet E. Subclinical immune reactions to viral infections may correlate with child and adolescent diagnosis of attention-deficit/hyperactivity disorder: a preliminary study from Turkey. Afr Health Sci 2014; 14:439-45. [PMID: 25320595 DOI: 10.4314/ahs.v14i2.21] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most common neuro-developmental disorders of childhood and adolescence. Studies focusing on the relationship of infectious agents and ADHD are scarce. It is also known that cerebellar injury may lead to hyperactive behavior. This study aimed to evaluate the relationship between viral agents of cerebellitis and the diagnosis of ADHD. METHODS The study group was formed of 60 consecutive ADHD patients and 30 healthy children. IgG levels for VZV; HSV-1, CMV, Measles, Mumps, Rubella and EBV were evaluated. RESULTS Males were significantly higher among patients with ADHD (65% vs. 40%, p=0.025). Patients with ADHD displayed significantly higher positivity for measles IgG (80% vs. 60%, p=0.044). When patients with ADHD were classified according to their pubertal status, adolescents with ADHD displayed higher positivity for mumps (100% vs. 74.4%, p=0.043). Most of the patients were diagnosed with ADHD-Combined or Hyperactive/Impulsive Subtypes (56.6%) while 43.3% were diagnosed with ADHD-predominantly inattentive type. When patients with subtypes of ADHD were compared in terms of seropositivity, it was found that patients with ADHD-Combined/ Hyperactive-Impulsive subtypes had significantly elevated reactions for Rubella (100% vs. 88.5%, p=0.044). CONCLUSION Although limited to a single center and may be prone to sampling biases, our results may support the notion that immune reactions may be related with ADHD among children and adolescents. Further, prospective studies from multiple centers are needed to support our findings and establish causality.
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Tian X, Zhang Y, Gu S, Fan Y, Sun Q, Zhang B, Yan S, Xu W, Ma X, Wang W. New coxsackievirus B4 genotype circulating in Inner Mongolia Autonomous Region, China. PLoS One 2014; 9:e90379. [PMID: 24595311 PMCID: PMC3940859 DOI: 10.1371/journal.pone.0090379] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/28/2014] [Indexed: 11/19/2022] Open
Abstract
Hand, foot, and mouth disease (HFMD) surveillance was initiated in the Inner Mongolia Autonomous Region of China in 2007, a crucial scrutiny for monitoring the prevalence of enterovirus serotypes associated with HFMD patients. However, this surveillance mostly focused on enterovirus 71 (EV-A71) and coxsackievirus A16; therefore, information on other enterovirus serotypes is limited. To identify the other circulating enterovirus serotypes in the HFMD outbreaks in Inner Mongolia in 2010, clinical samples from HFMD patients were investigated. Six coxsackievirus B4 (CVB4) strains were isolated and phylogenetic analyses of VP1 sequences were performed. Full-length genome sequences of two representative CVB4 isolates were acquired and similarity plot and bootscanning analyses were performed. The phylogenetic dendrogram indicated that all CVB4 strains could be divided into 5 genotypes (Genotypes I–V) with high bootstrap support (90–100%). The CVB4 prototype strain (JVB) was the sole member of genotype I. CVB4 strains belonging to genotype II, which were once common in Europe and the Americas, seemingly disappeared and gave way to genotype III and IV strains, which appear to be the dominant circulating strains in the world. All Chinese CVB4 strains belonged to Genotype V, a newly identified genotype supported by a high bootstrap value (100%), and are circulating only in mainland of China. Intertypic recombination occurred in the Chinese CVB4 strains with novel unknown serotype EV-B donor sequences. Two Chinese CVB4 strains had a virulent residue at position 129 of VP1, and one strain also had a virulent residue at position 16 of VP4. Increased surveillance is needed to monitor the emergence of new genetic lineages of enteroviruses in areas that are often associated with large-scale outbreaks. In addition, continued monitoring of enteroviruses by clinical surveillance and genetic characterization should be enhanced.
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Affiliation(s)
- Xiaoling Tian
- Inner Mongolia Center for Disease Control and Prevention, Hohhot City, Inner Mongolia Autonomous Region, People's Republic of China
| | - Yong Zhang
- WHO WPRO Regional Polio Reference Laboratory and Ministry of Health Key Laboratory for Medical Virology, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Suyi Gu
- Inner Mongolia Center for Disease Control and Prevention, Hohhot City, Inner Mongolia Autonomous Region, People's Republic of China
| | - Yaochun Fan
- Inner Mongolia Center for Disease Control and Prevention, Hohhot City, Inner Mongolia Autonomous Region, People's Republic of China
| | - Qiang Sun
- WHO WPRO Regional Polio Reference Laboratory and Ministry of Health Key Laboratory for Medical Virology, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Bo Zhang
- WHO WPRO Regional Polio Reference Laboratory and Ministry of Health Key Laboratory for Medical Virology, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Shaohong Yan
- Inner Mongolia Center for Disease Control and Prevention, Hohhot City, Inner Mongolia Autonomous Region, People's Republic of China
| | - Wenbo Xu
- WHO WPRO Regional Polio Reference Laboratory and Ministry of Health Key Laboratory for Medical Virology, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Xueen Ma
- Inner Mongolia Center for Disease Control and Prevention, Hohhot City, Inner Mongolia Autonomous Region, People's Republic of China
| | - Wenrui Wang
- Inner Mongolia Center for Disease Control and Prevention, Hohhot City, Inner Mongolia Autonomous Region, People's Republic of China
- * E-mail:
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Complete genome sequence of a recombinant coxsackievirus B4 from a patient with a fatal case of hand, foot, and mouth disease in Guangxi, China. J Virol 2012; 86:10901-2. [PMID: 22966193 DOI: 10.1128/jvi.01808-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The coxsackievirus B4 (CVB4) belongs to human enterovirus B species within the family Picornaviridae. Here we report a novel complete genome sequence of a recombinant CVB4 strain, CVB4/GX/10, which was isolated from a patient with a fatal case of hand, foot, and mouth disease in China. The complete genome consists of 7,293 nucleotides, excluding the 3' poly(A) tail, and has an open reading frame that maps between nucleotide positions 742 and 7293 and encodes a 2,183-amino-acid polyprotein. Phylogenetic analysis based on different genome regions reveals that CVB4/GX/10 is closest to a CVB4 strain, EPIHFMD-CLOSE CONTACT-16, in the 5' half (VP4∼2B) of the genome, although it is closer to a Chinese CVB5 strain, CVB5/Henan/2010, in the 3' half (2C∼3D) of the genome. Furthermore, similar bootscan analysis based on the whole genomes demonstrates that recombination has possibly occurred within the 2C domain and that CVB4/GX/10 is a possible progeny of intertypic recombination of the CVB4 strain EPIHFMD-CLOSE CONTACT-16 and CVB5/Henan/2010 that occurred during their cocirculation and evolution, which is a relatively common phenomenon in enteroviruses.
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Chu PY, Lu PL, Tsai YL, Hsi E, Yao CY, Chen YH, Hsu LC, Wang SY, Wu HS, Lin YY, Su HJ, Lin KH. Spatiotemporal phylogenetic analysis and molecular characterization of coxsackievirus A4. INFECTION GENETICS AND EVOLUTION 2011; 11:1426-35. [PMID: 21635970 DOI: 10.1016/j.meegid.2011.05.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 04/03/2011] [Accepted: 05/16/2011] [Indexed: 01/02/2023]
Abstract
Coxsackievirus A4 outbreaks occurred in Taiwan in 2004 and 2006. The spatiotemporal transmission of this error-prone RNA virus involves a continuous interaction between rapid sequence variation and natural selection. To elucidate the molecular characteristics of CV-A4 and the spatiotemporal dynamic changes in CV-A4 transmission, worldwide sequences of the 3' VP1 region (420 nt) obtained from GenBank were analyzed together with sequences isolated in Taiwan from 2002 to 2009. Sequences were characterized in terms of recombination, variability, and selection. Phylogenetic trees were constructed using neighbor-joining, maximum likelihood and Monte Carlo Markov Chain methods. Spatiotemporal dynamics of CV-A4 transmission were further estimated by a Bayesian statistical inference framework. No recombination was detected in the 420 nt region. The estimated evolution rate of CV-A4 was 8.65 × 10(-3) substitutions/site/year, and a purifying selection (d(N)/d(S)=0.032) was noted over the 3' VP1 region. All trees had similar topology: two genotypes (GI and GII), each including two subgenotypes (A and B), with the prototype and a Kenyan strain in separate branches. The results revealed that the virus first appeared in USA in 1950. Since 1998, it has evolved into the Kenya, GI-A (Asia) and GII-A (Asia and Europe) strains. Since 2004, GI-B and GII-B have evolved continuously and have remained prevalent. The co-existence of several positive selection lineages of GI-B in 2006 indicates that the subgenotype might have survived lineage extinction. This study revealed rapid lineage turnover of CV-A4 and the replacement of previously circulating strains by a new dominant variant. Therefore, continuous surveillance for further CV-A4 transmission is essential.
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Affiliation(s)
- Pei-Yu Chu
- Department of Medical Laboratory Science and Biotechnology, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan.
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