Classification of picornaviridae

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Abraham Thornton
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1 Epidemiology and etiological roles of two picornaviruses: human rhinovirus C and enterovirus 68 Tohoku University Graduate School of Medicine Hitoshi Oshitani Classification of picornaviridae Genus of Enterovirus Human enterovirus Human enterovirus A Human etnerovirus B Human enterovirus C Human enterovirus D Human rhinovirus Human rhinovirus A Human rhinovirus B Human rhinovirus C ICTV Picornaviridae Study Group

2 Human enteroviruses and rhinoviruses Common virological characteristics Positive strand, non enveroped virus Same genomic structure Pathogenesis and clinical diseases are different Enterovirus: Resistant to acid Causing enteric / systemic infections, e.g. poliovirus Rhinovirus: Sensitive to acid Only respiratory infection Human rhinoviruses Human enteroviruses Simmonds P et. al. J Gen Virol 2010 vol. 91 no Human enteroviruses and rhinoviruses Respiratory infection Enteric / systemic infection Human rhinovirus A Enterovirus 68 Human enteroviruses Human rhinovirus B Human rhinovirus C??

3 Background of the study Etiological study on pediatric pneumonia Eastern Visayas Regional Medical Center, Taclobal City, Leyte Island in the Philippines May 2009 present Part of J GRID (Japan Initiative for Global Research Network on Infectious Diseases) supported by the Japanese government Tacloban Pediatric Pneumonia Study Patients Aged between 7 days and 14 years Severe pneumonia by the definition of Integrated Management of Childhood Illness (IMCI) Respiratory viruses were detected by multiplex PCR

4 Eastern Visayas Regional Medical Center (EVRMC) Outcome of patients HAMA- Improved, 151, 18% Others, 30, 4% Died, 70, 9% HAMA- Deteriorated, 18, 2% May 2008 May 2009 (n = 819) Discharged, 550, 67% HAMA: Home against medical advice

5 Identified viruses RSV-A Negative RSV-B Rhino-A Multiple WU/KI Corona Boca EV68 Adeno Rhino-B Rhino-C hmpv FluA FluB May 2008 May 2009 (n = 819) Viruses were detected in 506 cases (61.2 %) Identified viruses RSV-A Negative RSV-B Rhino-A Multiple WU/KI Corona Boca EV68 Adeno Rhino-B Rhino-C hmpv FluA FluB May 2008 May 2009 (n = 819) Viruses were detected in 506 cases (61.2 %)

6 Enterovirus Detected from hospitalized children with respiratory infection in Only sporadic cases have been reported 2. Acid sensitive, grows at lower optimal temperture EV68 HRV Other EV Acid sensitive Yes Yes No Optimum growth temp Respiratory tract Intestine (Mainly) * HRV and EV68 shares phenotypic characterizations 2. Isolation is relatively difficult. Classification of Human Enteroviruses Coxsackievirus B1 6, Coxsackievirus A9, Enterovirus 69, 73, 74, 75, 77, 78, Echovirus1 7, 9,11 21,24 27,29 33 Coxsackievirus A1,11,13,15,17 22,24 Species Japan USA A 3613(48%) 1520(3.3%) B 3949(52%) 44418(96.3%) C 7 (0.09%) 176(0.38%) D 14(0.18%) 26 (0.05%) (From enterovirus surveillance data) Enterovirus 68,70, 94 Poliovirus 1 3 Only 3 serotypes in Human enterovirus D Detection of human enterovirus D has been very rare Coxsackievirus A2 10, 12,14,16 & Enterovirus 71,76

7 Methods 1) Amplify partial viral genome by RT PCR Screen samples by PCR targeting 5 NTR of HRV Submit positive samples to PCR targeting VP1 of EV68 Genetic analysis using Mega 3.1 software 2) Epidemiological analysis using collected patients information Enterovirus 68 was detected from 21 cases with severe pneumonia, from October 2008 and February 2009, 2 of them died Eastern Visayas region Babatngon Basey Tacloban city 0 200km 0 5km Palo Dulag N Imamura T et al. Emerg Infect Dis. Vol 17: , 2011

8 Phylogenetic tree (5 NTR) EV68 5 NCR(232bp) Bootstrap x500 Phylogenetic tree (VP1) EV68, Philippines EV68, USA EV68, France VP1(296bp) Bootstrap x500

9 Enterovirus 68 detection in Japan Increased detection of enterovirus 68 in 2010 in Japan Infectious Agents Surveillance Report, NIID, Japan Increased detection of Enterovirus 68 MMWR (in press) Increased detection of enterovirus 68 in Philippines ( ), USA ( ), Japan (2010) and Netherland (2010)

10 Recent increase in Enterovirus 68 in different parts of the world Two possibilities Increased detection Most studies detected Enterovirus 68 by PCR targeting rhinovirus detection Global epidemic Due to emergence of different virus: antigenicity, virulence, transmissibility Phylogenetic tree of recent enterovirus 68 Japan (Yamagata) Japan (Sendai) Japan (Osaka) Philippines Nederland

11 Human rhinovirus C Newly identified species of human rhinovirus No virus isolation technique established Phonotypic characteristics and pathogenesis are largely unknown Associated with more severe respiratory infections? Renwick et al JID 2007; 196: Monthly distribution of HRVs HRVs 447 (28.9 %) 229 HRVA (14.3%) HRVB 32 (2.0%) HRVC 186 (11.6%) Total 1597

12 Phylogenetic trees of detected rhinoviruses HRVA HRVB HRVC Many different genotypes were seen for HRVA, HRVB and HRVC No significant clustering HRV A HRVB HRVC 10 % died No death Wheezing 4 % died Wheezing was more frequently seen in HRVC than HRVA

13 Detection of rhinovirus RNA in serum samples Serum that were collected from whose nasopharyngeal samples were pos. for HRVs Nasopharyngeal swabs (n=816) serum Positivity (%) Sample No. Serum- positivity (%) OR (95%CI) HRVA 135 (16.5%) (3%) * 0.22 ( ) HRVB 25 (3.1%) 25 0** - HRVC 83 (10.2%) (31.3%)* 6.84 ( ) Total (12.3%) Ref HRVs *p<0.01, **p<0.05 Serum positive rates: HRVC >> HRVA > HRVB HRVC may be associated with viremia more often than HRVA and HRVB Fuji N et al (submitted) HRVA HRVB Number of cases Number of cases 7.7% 3.6% 5.9% Days after the onset HRVC Days after the onset Number of cases 60.0% 36.8% 25.0% 14.3% 14.3% 11.1% 20% Days after the onset Positive rate peaked 2 days after onset Fuji N et al (submitted)

14 HRV B HRVC HRV A Serum positive HRVC were distributed in almost all genotypes Serum positive HRVA were found in certain genotypes which are close to HRVC in 5 NCR sequence HRVC Serum sample positive Conclusion Enterovirus 68 (EV68) EV 68 was detected from 21 cases with severe respiratory infections Subsequently increased detection of EV 68 was reported from Japan, USA, and Europe EV 68 can be an important cause of respiratory infection Human Rhinovirus C (HRVC) HRVC was detected from 11.6 % of cases with severe respiratory infections HRVC causes viremia more often and may have different pathogenesis from HRVA and HRVB

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