Molecular characterization of human rhinovirus field strains isolated during surveillance of enteroviruses

Abstract

Human rhinoviruses (HRVs), which are the most frequent causative agents of acute upper respiratory tract infections, are abundant worldwide. We have identified HRV strains in environmental specimens collected in Finland, Latvia and Slovakia during the surveillance of polioand other enteroviruses. These acid-sensitive HRV strains were isolated under conditions optimized for growth of most of the enteroviruses, i.e. in stationary human rhabdomyosarcoma cells incubated at 36 6C. Phylogenetic analysis of the sequences derived from the partial 59 noncoding region and the capsid region coding for proteins VP4/VP2 and VP1 showed that the HRV field strains clustered together with prototype strains of the HRV minor receptor group. Partial sequences of the 3D polymerase coding region generally followed this pattern, with the exception of a set of three HRV field strains that formed a subcluster not close to any of the established HRV-A types, suggesting that recombination may have occurred during evolution of these HRV strains. Phylogenetic analysis of the VP4/VP2 capsid protein coding region showed that the 'environmental' HRV field strains were practically identical to HRV strains recently sequenced by others in Australia, the United States and Japan. Analysis of amino acids corresponding to the intercellular adhesion molecule-1 receptor footprint in major receptor group HRVs and also in the low-density lipoprotein receptor footprint of minor receptor group HRVs showed conservation of the 'minor receptor group-like' amino acids, indicating that the field strains may have maintained their minor receptor group specificity. INTRODUCTIONHuman rhinoviruses (HRVs) belong to the family Picornaviridae and together with human enteroviruses (HEV) and a number of non-human enterovirus strains comprise the largest genus (Enterovirus) in the family (Knowles, 2008). Clinical illnesses caused by HRV are typically mild and self-limiting upper respiratory tract infections or common colds, but HRVs have also been increasingly associated with other clinical consequences of respiratory tract infection such as acute otitis media (NoksoKoivisto et al., 2004;Pitkaranta et al., 1998;Vesa et al., 2001), acute community-acquired sinusitis (Pitkaranta et al., 1997(Pitkaranta et al., , 2001), bronchiolitis (Hayden, 2004), pneumonia (Papadopoulos, 2004 and exacerbations of existing respiratory disorders such as asthma (Gern, 2002) and chronic obstructive pulmonary disease (Greenberg, 2002).HRV encompasses 100 designated serotypes, including two antigenically distinct subtypes of serotype HRV1 (HRV1A and HRV1B) (Hamparian et al., 1987;Kapikian et al., 1967Kapikian et al., , 1971. The current taxonomy is based on genetic relationships of HRV. Genetic analysis of VP4/VP2 (Savolainen et al., 2002a) and VP1 (Laine et al., 2005; Ledford et al., 2004) capsid protein coding regions showed that the 100 serotypes cluster into two genetically distinct species, HRV-A and HRV-B. One HRV strain originally assigned as HRV87 belongs to the enterovirus species H...

High detection frequency and viral loads of human rhinovirus species A to C in fecal samples; diagnostic and clinical implications

“…The frequent detection and high viral loads of HRV in fecal samples in the current study is consistent with the frequent detection of HRV by virus isolation during environmental screening of human sewage [Blomqvist et al, 2009]. It was speculated that the HRV variants derived from respiratory secretions carried into sewage by discarded used tissues or in wastewater.…”

“…Experimentally, HRVs differ from enteroviruses in being inactivated at pH of <5 as well as pH values above 9–10. For this reason, HRV detection in fecal samples or sewage has generally been attributed in the past to swallowed respiratory secretions [Blomqvist et al, 2009]. In our opinion, this is unlikely for two reasons; firstly, the acid lability of HRVs that destroys their infectivity when passing through the stomach would lead to HRV RNA degradation if the virion capsid was breached.…”

Prevalence and genetic diversity of waterborne pathogenic viruses in surface waters of tropical urban catchments

“…One possible explanation could be that human rhinoviruses derived from respiratory secretions were carried into the canal by discarded used tissues or leaking sewage. More recently, the identification of HRV‐A in sewage specimens collected from Finland, Latvia and Slovakia has been reported for the first time (Blomqvist et al. 2009).…”

Rhinoviruses

“…Predictions of infrequent recombination among the HRVs [ 83 ] have been made based on examination of the available set of HRV coding and noncoding regions [ 152 ]. Intensive analyses reported that recombination is not a driving force for the evolution of HRV types [ 144 , 153 , 154 ].…”