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New respiratory viruses
Dr Klara Pósfay Barbe
Hôpital des Enfants Geneva, Switzerland
2nd Pediatric Infectious Disease Training Course
Respiratory tract infections § Leading cause worldwide of morbidity and
mortality (5 Mio in kids < 5yo/y from resp virus) § Etiologic agent often unknown
– E.i.: CAP cultures detected agents in only 46% § Most LRTI due to viruses: max 40% viruses
identified even with PCR § In children: RSV, parainfluenza viruses,
influenza = major causes of bronchiolitis and LRTI
§ Ease of spread; children 23x more infected than adults
Ruiz M et al; Am J Respir Crit Care Med 1999; 160:397
Until recently
RSV parainfluenza influenza rhinovirus …
Etiologies of LRTI & URTI in children
???
History § Since 2001, many new human viruses
discovered thanks to molecular techniques – Amplification by random PCR
(a procedure using a generic primer sequence with a random 3' end)
– Cloning of the PCR products – Largescale sequencing of the clones – Automated editing and database
searches of the sequencing results
Rhinovirus
Influenza
RSV
Parainfluenza
Hum. metapn.
Coronavirus
Enterovirus
Adenovirus
Bocavirus
1956, 2007 “new HRVs”
1933
1956
1956
2001
1965, SARS, NL63, HKU1 200305
1940s 50s
1953
2005
Panel of > 20 RTPCR assays
Lecture outline
§ New respiratory viruses: why are they important? § Human metapneumovirus (hMPV) § Coronavirus NL63 (HCoV) § Bocavirus (HBoV)
Respiratory tract infections : why are they important?
§ Cohort of 197 newborns in Bern § Weekly standardized interview § First acute respiratory infection with
cough or wheeze § Nasopharyngeal swab: baseline & at
week 3
Kaiser L et al PIDJ 2006; Regamey N et al. PIDJ 2007
Respiratory tract infections during the first year of life
0.00 0.25 0.50 0.75 1.00 0
25
50
75
100
age (years)
% of infants with
ARI
16% virus negative
84% virus positive
112 episodes in 197 newborns (67%)
Regamey N et al. PIDJ 2007
Visit to general practitioners
HRV HCoV PIV RSV HMPV Others Mixed No virus 0
10
20
30
40
50
60
70
% of cases with
visit to GP
Regamey N et al. PIDJ 2007
Severity of symptoms
HRV HCoV PIV RSV Others Mixed No virus
0
1
2
3
4
5
6
7
8
9
Total sym
ptom
severity
score
„Commoncold“ viruses
„Classical“ viruses
p=0.57 p=0.002
p=0.01
HRV HCoV PIV RSV Others Mixed No virus
0
1
2
3
4
5
6
7
8
9
Total sym
ptom
severity
score
„Commoncold“ viruses
„Classical“ viruses
p=0.57 p=0.002
p=0.01
Regamey N et al. PIDJ 2007
Viral distribution
38%
Virus n (%)
RSV A – B 17 (15.2) Para 1 – 3 19 (17.0) Flu A – B 4 (3.6) Adenovirus 3 (2.7)
38
Virus n (%)
RSV A – B 17 (15.2) Para 1 – 3 19 (17.0) Flu A – B 4 (3.6) Adenovirus 3 (2.7)
48%
Rhinovirus 26 (23.2)
Coronavirus OC43 7 (6.3) Coronavirus E229 3 (2.7) Coronavirus NL63 9 (8.0) Coronavirus HKU1 1 (0.9)
Metapneumovirus 2 (1.8)
43%
Rhinovirus 26 (23.2)
Coronavirus OC43 7 (6.3) Coronavirus E229 3 (2.7) Coronavirus NL63 9 (8.0) Coronavirus HKU1 1 (0.9)
Metapneumovirus 2 (1.8)
Dual or triple infections in 9 cases
Virus negative 16%
Regamey N et al. PIDJ 2007
Conclusion
§ These “unknown” viruses might have an important
– Clinical impact – Socioeconomic impact – Longterm impact (asthma, bronchiectasis,
etc.) – Infection control issues
Lecture outline
§ New respiratory viruses: why are they important? § Human metapneumovirus (hMPV) § Coronavirus NL63 (HCoV) § Bocavirus (HBoV) § Others?
Human metapneumovirus (hMPV)
§ First described in 2001 § Has been circulating for > 50 years
(banked serologies) § By the age of 5 yo, ~100% have
serological evidence of hMPV infection
van den Hoogen BG et al. Nat Med 2001; 7: 719 Leung J et al. J Clin Microbiol 2005; 43:1213
hMPV: the virus § Paramyxovirus (subfamily Pneumovirinae) § Enveloped, singlestranded RNA virus of negative
polarity (genome must be transcribed to mRNA to be translated into protein)
§ Different from RSV: lacks 2 nonstructural proteins and has a slightly different gene order
§ Two main lineages: A (A1 & A2) and B (B1 & B2) § Nucleotide sequence variation between A & B:
11.847.7% § Different genotypes may cocirculate during the
same year
Mackay Im et al. J Infect Dis 2004; 190:1913 Principi N et al. Clin Microbiol Infect 2006; 12: 301
Most frequent? More severe?
hMPV: local changes § Increased inflammatory cell infiltrates
(mononuclear mostly) in the lung interstitium § Increased myofibroblast thickening
near airway epithelium § Cell degeneration/necrosis § Can persist several weeks in the lungs
despite immune response (strategy to overcome host defense?)
Alvarez R et al. J Virol 2004; 78:6927
Day 0 Day 2
Day 4 Day 7
Day 10 Day 14
Alvarez R et al. J Virol 2004; 78:6927
Histopathology of HMPV infection in mice. Interstitial inflammatory cell infiltrates were examined in the lung
hMPV: epidemiology
§ Worldwide distribution § Season: overlap with RSV & influenza § Mostly found in infants, young children,
elderly and immunocompromised § Uncommon asymptomatic infection
Williams JV et al. NEJM 2004; 350:443
hMPV: clinical manifestations
§ Causes URI and LRTI (pneumonia) § Often bronchiolitis § Associated with
– Febrile seizures – Rash – Diarrhea – Enlarged liver – Altered liver function tests
Peiris JS et al. Emerg Infect Dis 2003; 9:628
hMPV: diagnosis
§ Poor replication in cell culture § Cytopathic effect in certain cell lines
only § Confirmation by RTPCR § New assays ≤ 2 hours § Serologies by ELISA? § Stays detectable by PCR for 1 month in
NP aspirate at room temperature Bonroy C et al. Clin Microbiol Infect 2007; 13: 504
Difference between hMPV & RSV & influenza viruses
§ 1505 children: RTPCR of NP swabs – 2.8% hMPV; 9.5%* RSV; 15.3%* influenza viruses – 16.7% dual infection (1x RSV, 6x flu) – hMPV+: all acute respiratory infection – Fever* if hMPV + & influenza + § Families more sick, more medical visits, more
antipyretics than RSV+ è socioeconomic impact – Wheezing* if hMPV+& RSV+
Bosis S et al. J Med Virol 2005; 75(1): 101 Principi N et al. Clin Microbiol Infect 2006; 12: 301
hMPV & RSV coinfection § 45 infants ventilated for RSV bronchiolitis:
bronchoalveolar lavage ; RTPCR for hMPV § BAL cytokines & chemokine by ELISA
§ 68% also hMPV positive (demographics, symptoms° and PICU data similar if RSV+ / hMPV+ or )
° except for length of time between symptoms and intubation (longer if dual)
§ No difference in cellularity, cytokines (TNF, IFNγ, IL 4,9,10,13) and chemokines (CXCL8 &10, CCL2, 3,5,11): timing? different production sites?
McNamara PS et al. Pediatr Pulmonol 2007 Mejias A et al. ICAAC 2007; V1258
§ Other studies – If PICU for RSV+ bronchiolitis, 70% co
infected with hMPV – 10x increase RR of admission in PICU for
mechanical ventilation if RSV+ & hMPV+, especially if < 3 years old
In contrast: hMPV & RSV co infection
Greensill J et al. Emerg Infect Dis 2003; 9:372 Semple MG et al. JID 2005; 191:382 Konig B et al. J Clin Microbiol 2004; 42:4632
è Influences the severity of RSV infection?
hMPV & other viruses
§ 185 noninfluenza clinical samples (NP, sputum, throat, tracheal) in pediatrics § 22.2% hMPV positive § Coinfection with adenovirus or SARS
possible § Cause of underestimation of burden of
disease : only other virusnegative tested for hMPV?
Kaida A et al. Microbiol Immunol 2007
hMPV & bacteria
§ Coinfection with S. pneumoniae plays a role in inducing lower respiratory tract infection § Other bacteria coinfection:
– S. aureus, Stenotrophomonas maltophilia: clinical link not determined
Madhi SA et al. JID 2006 Boivin G et al. JID 2002
hMPV in Switzerland
§ 1’500 NP samples (PCR for hMPV) in children with respiratory illness § 5% + hMPV (vs 19.5% RSV) § hMPV:
– mean age 32 mo* (vs 16 mo) – 45% admitted (vs 54%) – 18% intensive care (vs 8%)[70% dual infection] – 77% LRTI
Baer G et al; Eur J Pediatr 2007
Treatment for hMPV
§ No treatment available § Monoclonal antibody (mAb 338)
against the fusion protein of hMPV in mouse model – Decreased viral titers – Decreased airway obstruction – Less severe perivascular, alveolar and
interstitial inflammation on day 5 & 42
Hamelin M et al; ICAAC 2007; V1259
Treatment for hMPV § hMPV fusion protein (F) is most
important target of protective immunity
§ Production of a fully human monoclonal antibody fragment (Fab DS7)
§ Fab intranasally 3 days post hMPV infection
§ 24 hours later: – > 1500fold reduction in viral titers
in lungs if treated – 4fold reduction in nasal tissues – Doseresponse
Williams JV et al. J Virol 2007; 81(15): 8315
Nose
Lung
Coronavirus
The common cold virus
Coronaviruses: HCoV
§ SARSCoV most aggressive human CoV probably originated in wild animal reservoir
Masters PS. Adv Virus Res. 2006;66:193
Other theory
Coronaviruses § 1960s: HCoVOC43 & 229E: common colds § 2003: SARSCoV § 2003: HCoVNL63 § 2004: HCoVHKU1
§ Worldwide distribution § Positivestranded RNA viruses (largest viral genome
among RNA viruses); spiked membrane proteins (crownlike structure!)
Not tested in humans, No animal models, No cultures possible for HKU
Masters PS. Adv Virus Res. 2006;66:193
HCoVNL63 § Closely related to HCoV229E (65% sequence identity)
§ 1240 NP specimen (negative for other known viruses) in children with ARI – 2.1% positive for HCoVNL63 – Mostly FebruaryMarch (none AugustNovember)
– 7 days 9.5 years (mostly < 1yo) – Male: female= 2: 1
§ Shares with SARSCoV receptor for target cell entry (treatment ??)
Bastien N et al. J Clin Microbiol 2005; 43: 4567 Esper F et al. JID 2005; 191:492 Van der Hoek L et al. PLoS Med 2005; 2:e240
In literature: 1.38.8%
Except in HongKong: Springsummer
HCoV: clinical presentation § Severe LRTI, pneumonia, bronchiolitis, but usually not
lethal § URTI (fever, cough , rhinorrhea)
– up to 40° ; mean duration 2.6 days +/1.2 days (≠RSV or Influenza A)
§ Febrile seizures: – 38% HCoVHKU1 – 6% HCoVOC43
§ Typical of CoVNL63: croup (6.6 x more likely if +)
§ Mostly in children, adults with underlying disease or elderly
§ More often found in outpatients Van der Hoek L. Antiviral Therapy 2007; 12: 651 Hayden FG. Curr Opin Infect Dis 2006; 19:169
P< 0.05
HCoVNL63
§ Coinfection frequent >50% (influenza, RSV,…)
§ Nosocomial acquisition? § Lifelong immunity? Adults + maternal
antibodies not efficient? § Viral load high in NP during first 12 days,
than decreases (=influenza, ≠ SARS)
Chiu SS et al. CID 2005; 40:1721 Wu PS et al. Eur J Pediatr 2007; Feb Van der Hoek L et al. PLoS Med 2005
HCoV in Switzerland
Birth cohort § 7% HCoVNL63 § 9% other coronaviruses § ½ cases were negative by PCR 3
weeks after onset of illness § But…½ cases were positive by PCR 3
weeks after onset, even if symptom free
Kaiser L et al. PIDJ; 2005; 24: 1015
HCoVNL63: importance § 2’060 children < 15 yo
in ER: NP aspirates (RTPCR) § HCoV: 79 cases(3.8%)
– 72.2% only HCoV – 13 cases HCoVNL63 – Mild disease – Few secondary cases
§ 1890 patients with pneumonia (RTPCR) § HCoV: 64 cases (3.3%)
– 69.5% only HCoV – 8 cases HCoVNL63 – Association between
HCoVNL63 & pneumonia = protective!
Esposito S et al. J Med Virol 2006; 78:1609 Dare RK et al. JID 2007; 196: 1321
Limited clinical and socioeconomic impact of HCoVNL63
HCoV: treatment
§ IVIG seems to be a HCoVNL63 inhibitor § Inhibition of viral replication via peptides
derived from HR2 domain § Inhibition of viral replication through RNA
interference § Transcriptional level: pyrimidine analogues § Protease inhibitors (posttranslational
processing): for ex. N3
Van der Hoek L et al. FEMS Microbiol Rev 2006; 30:760
Human Bocavirus (HBoV)
HBoV § 2005: described by Allander et al § Close to Parvovirus § Worldwide distribution § Mainly in children > 6 mo (=hMPV, ≠RSV) &
less than 24 mo § Few reports in adults § Detection by RTPCR § Transmission? Nosocomial? § Incubation time?
Allander T et al. Proc Natl Acad Sci USA 2005; 102:12891 Völz S et al. J Clin Virol 2007; 40: 229
no culture, no animal model
HBoV: infection
§ In animals, similar viruses cause diarrhea (Bovine parvovirus; Canine minute virus)
§ Doesn’t (yet?) fulfill Koch’s postulates – Frequency increased if symptomatic
Koch’s postulates
1. The microorganism must be found in all organisms suffering from the disease (but not in healthy organisms)
2. The microorganism must be isolated from a diseased organism and grown in pure culture
3. The cultured microorganism should cause disease when introduced into a healthy organism
4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent
HBoV: infection
§ Associated with resp. tract infections – Cough, rhinorrhea, fever up to 39.5°
§ Associated with gastrointestinal disease (~25%?) – Vomiting, diarrhea – Fecal excretion
§ Seasonality: late winterearly spring? Canada: no preferred season
Arnold JC et al. CID 2006; 43:283 Vicente D et al; Emerg Infect Dis 2007; 13: 636 Bastien N et al. J Clin Microbiol 2006; 12: 848
Völz S et al. 2007
HBoV: prevalence § Range (0) 1.519% § In Switzerland (healthy birth cohort):
– 4.5% – 80% associated with other virus – Rapidly cleared (< 3 weeks, except for 1
patient) § Probably lifelong immunity (same
strain for RTI and diarrhea; lack of variation in the surface protein)
Regamey N et al. 2007; PIDJ; 26: 147
95 1.6 yo 19 259 Allander T 2007
Same season RTI
& fecal
33 56
< 5 years 5 / 6.9; 2.1
400/1200; 1435 fecal
Lau SKP 2007
< 5 years 0.8 962 with gi sympt
Lee JI 2007
71 0adults 13.8; 43!!!; 0.8
225 symp kids; 100 asympto;
126 adults with COPD or
pneumonia
Longtin J 2007 (ICAAC)
Found in stool and
urine
60 < 14 yo 13.4 917 Pozo 2007
Coinfection= modifyer of
disease?
36 9 mo (317)
2.8 389 Völz 2007
Coinf %
Age (range)
+HBoV in %
N
HBoV: Coinfections
§ RSV § Adenovirus § Rhinovirus § Norovirus § Other respiratory viruses § Rotavirus, astrovirus, … § Several viruses
Pozo F et al. J Clin Virol 2007; 40: 224 Völz S et al 2007
HBoV: to think about….
§ 16 patients with Kawasaki disease § 31.2% + for HBoV
§ 259 children admitted for wheezing: – PCR, Cultures, Ag detection, serologies
(16 viruses): 95% + results (19% HBoV) – High viral loads if HBoV alone & wheezing – Found also in serum: systemic infection
CatalanoPons C et al. Clin Microbiol Infect 2007; 13: 1220 Allander T et al. CID 2007; 44: 904
In summary: hMPV, HCoV& HBoV
§ In common
– Worldwide distribution – Season: end of winter – Children (elderly) – URTI & LRTI – Coinfections frequent – No treatment….yet
In summary: hMPV, HCoV& HBoV
~not in adults? 2:1 male: female
Two strains: co circulation
positive
Kawasaki? Mild illness Influences severity of RSV?
Also gastrointestinal
disease
Croup Bronchiolitis
624 mo <1 yo Age: 23 yo
HBoV HCoVNL63 hMPV
Are we done?
Preview…
§ Characterisation of a newly identified human rhinovirus, HRVQPM, discovered in infants with bronchiolitis § Identification of a third polyomavirus § Identification of a Novel Human
Polyomavirus from patients with ARTI (= KI & WU polyomaviruses)
P. McErlean et al. J Clin Virology; 2007; 39: 67 Allander T et al. J Virol; 2007 Gaynor AM PLoS Pathogens, in press
Papers to read
hMPV Principi N et al. Human Metapneumovirus in paediatric patients.
Clin Microbiol Infect 2006; 12: 301308
HCoV (NL63) Van der Hoek L. Human coronaviruses: what do they cause?
Antiviral Therapy 2007; 12: 651658 Pyrc K et al. The novel Human Coronavirus NL63 and HKU1. J Virol
2007; 81(7): 30517
HBoV Völz S et al; Prospective study of HBoV infection in pediatric
university hospital in Germany 2005/2006. J Clin Virol 2007; 40:229235