Clinical severity and molecular typing of human rhinovirus C strains during a fall outbreak affecting hospitalized patients.
BACKGROUND
The circulation rate and the clinical severity of infections caused by members of the new human rhinovirus C (HRV-C) species remain to be defined.


OBJECTIVE
To investigate the epidemiologic and clinical impact of HRV-C strains in a fall outbreak interesting hospitalized patients.


METHODS
HRV species (A-C) were determined by phylogenetic analysis following amplification of two genome regions (5'NCR and VP4/VP2) by RT-PCR. HRV species were correlated with age, respiratory tract involvement, clinical symptoms, and HRV load in respiratory secretions.


RESULTS
During the first week of the period October-November 2008, single HRV infections were associated with 95% of all respiratory syndromes affecting hospitalized patients. Then, HRV infections (single+coinfections) interested about 90% of positive samples until the end of October, when they declined in frequency until reaching about 30% at the end of November. Overall, 104 HRV strains were detected and, of these, 90 could be classified by phylogenetic analysis, as follows: 45 HRV-A, 12 HRV-B, 28 HRV-C, and 5 human enterovirus D strains. HRV-C identity was confirmed by detection of cis-acting replication elements (cre) in 23/23 strains. As for severity of respiratory syndromes, unlike HRV-A and HRV-B strains, HRV-C strains were responsible for a significantly higher rate (p<0.05) of lower respiratory tract infections in the pediatric as compared to adult patient population.


CONCLUSIONS
HRV-C strains have been shown to circulate at a rate intermediate between HRV-A and HRV-B strains, showing a greater degree of clinical severity in the pediatric population.
Piralla
A
A
Servizio di Virologia, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy.
Rovida
F
F
Campanini
G
G
Rognoni
V
V
Marchi
A
A
Locatelli
F
F
Gerna
G
G
D000328:Adult; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D003428:Cross Infection / Q000453:epidemiology* / Q000473:pathology* / Q000503:physiopathology / Q000821:virology; D004196:Disease Outbreaks; D005838:Genotype; D006801:Humans; D007223:Infant; D010802:Phylogeny; D010850:Picornaviridae Infections / Q000453:epidemiology* / Q000473:pathology* / Q000503:physiopathology / Q000821:virology; D012367:RNA, Viral / Q000235:genetics; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000473:pathology / Q000503:physiopathology / Q000821:virology; D012229:Rhinovirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D012720:Severity of Illness Index; D019562:Viral Load; D055815:Young Adult
D012367:RNA, Viral