Human rhinovirus infection in young African children with acute wheezing
BMC Infectious Diseases
Human rhinovirus infection in young African children with acute wheezing
Heidi E Smuts 0
Lesley J Workman 2
Heather J Zar 1
0 Division Medical Virology/NHLS, Department of Clinical Laboratory Sciences, University of Cape Town , Cape Town , South Africa
1 Department of Paediatrics and Child Health, University of Cape Town, Red Cross War Memorial Children's Hospital , Cape Town , South Africa
2 Division of Clinical Pharmacology, Department of Medicine, University of Cape Town , Cape Town , South Africa
Background: Infections caused by human rhinoviruses (HRVs) are important triggers of wheezing in young children. Wheezy illness has increasingly been recognised as an important cause of morbidity in African children, but there is little information on the contribution of HRV to this. The aim of this study was to determine the role of HRV as a cause of acute wheezing in South African children. Methods: Two hundred and twenty children presenting consecutively at a tertiary children's hospital with a wheezing illness from May 2004 to November 2005 were prospectively enrolled. A nasal swab was taken and reverse transcription PCR used to screen the samples for HRV. The presence of human metapneumovirus, human bocavirus and human coronavirus-NL63 was assessed in all samples using PCR-based assays. A general shell vial culture using a pool of monoclonal antibodies was used to detect other common respiratory viruses on 26% of samples. Phylogenetic analysis to determine circulating HRV species was performed on a portion of HRV-positive samples. Categorical characteristics were analysed using Fisher's Exact test. Results: HRV was detected in 128 (58.2%) of children, most (72%) of whom were under 2 years of age. Presenting symptoms between the HRV-positive and negative groups were similar. Most illness was managed with ambulatory therapy, but 45 (35%) were hospitalized for treatment and 3 (2%) were admitted to intensive care. There were no in-hospital deaths. All 3 species of HRV were detected with HRV-C being the most common (52%) followed by HRV-A (37%) and HRV-B (11%). Infection with other respiratory viruses occurred in 20/128 (16%) of HRV-positive children and in 26/92 (28%) of HRV-negative samples. Conclusion: HRV may be the commonest viral infection in young South African children with acute wheezing. Infection is associated with mild or moderate clinical disease.
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Background
Wheezing is a frequent manifestation of lower
respiratory tract infection (LRTI) in infants and young
children. Viral infections are the commonest cause of acute
wheezing. Several respiratory viruses, including
respiratory syncytial virus (RSV), influenza viruses,
parainfluenza viruses, enteroviruses, human coronaviruses,
human metapneumovirus and human bocavirus have
been associated with wheezy illness [1-5].
With the improvement of molecular techniques the
frequency of HRV detection in clinical samples has
increased dramatically [6-8] providing increasing
evidence that HRV infection may be associated with LRTI
including bronchiolitis, pneumonia, asthma
exacerbations or influenza-like illnesses [9]. A recent
populationbased study showed that HRV was detected in 26% of
children under 5 years of age hospitalized with
respiratory symptoms or fever [10]. Subsequently, studies in
high income countries have confirmed the importance of
HRV as a cause of severe LRTI in young children
requiring hospitalization [11,12]. It is unclear if the diverse
spectrum of clinical illnesses associated with HRV
infection is related to host factors, the infecting HRV type
or both. Recent evidence suggests that infection with
HRV-C may result in more severe disease [12-16].
Since the first isolation of HRV in 1953 [17]
approximately 100 serotypes have been described and new types
are being discovered indicating that this genus is
considerably more varied than previously recognized. Based on
sequence analysis, antiviral susceptibilities and receptor
usage HRV was until recently divided into 2 groups;
HRV-A and HRV-B [18]. However, a third and possible
fourth grouping, HRV-C and HRV-D, have been
identified after sequence analysis of HRV types identified some
which did not cluster with HRV-A, HRV-B or other
species within the genus Enterovirus [15,16,19-23]. HRV-C
has a global distribution, with a prevalence intermediate
with HRV-A and HRV-B [24].
The importance of HRV as a cause of acute wheezing
illness in infants and young children has not been
studied in African children. The aim of this study was to
investigate the prevalence of HRV in African children
with acute wheezing.
Methods
Study design
A prospective study of children aged 2 months to 5 years
presenting with acute wheezing to Red Cross War
Memorial Childrens Hospital (RCCH) from May 2004 to
November 2005 (2 winter seasons) was undertaken.
RCCH is a public paediatric tertiary hospital in Cape
Town, South Africa that provides care to children mostly
from poor socio-economic ba (...truncated)