Screening respiratory samples for detection of human rhinoviruses (HRVs) and enteroviruses: comprehensive VP4-VP2 typing reveals high incidence and genetic diversity of HRV species C.

Rhinovirus infections are the most common cause of viral illness in humans, and there is increasing evidence of their etiological role in severe acute respiratory tract infections (ARTIs). Human rhinoviruses (HRVs) are classified into two species, species A and B, which contain over 100 serotypes, and a recently discovered genetically heterogeneous third species (HRV species C). To investigate their diversity and population turnover, screening for the detection and the genetic characterization of HRV variants in diagnostic respiratory samples was performed by using nested primers for the efficient amplification of the VP4-VP2 region of HRV (and enterovirus) species and serotype identification. HRV species A, B, and C variants were detected in 14%, 1.8%, and 6.8%, respectively, of 456 diagnostic respiratory samples from 345 subjects (6 samples also contained enteroviruses), predominantly among children under age 10 years. HRV species A and B variants were remarkably heterogeneous, with 22 and 6 different serotypes, respectively, detected among 73 positive samples. Similarly, by using a pairwise distance threshold of 0.1, species C variants occurring worldwide were provisionally assigned to 47 different types, of which 15 were present among samples from Edinburgh, United Kingdom. There was a rapid turnover of variants, with only 5 of 43 serotypes detected during both sampling periods. By using divergence thresholds and phylogenetic analysis, several species A and C variants could provisionally be assigned to new types. An initial investigation of the clinical differences between rhinovirus species found HRV species C to be nearly twice as frequently associated with ARTIs than other rhinovirus species, which matches the frequencies of detection of respiratory syncytial virus. The study demonstrates the extraordinary genetic diversity of HRVs, their rapid population turnover, and their extensive involvement in childhood respiratory disease.

Direct identification of human enterovirus serotypes in cerebrospinal fluid by amplification and sequencing of the VP1 region.

BACKGROUND: Human enteroviruses (HEV) are a major cause of meningitis and other neurological disease. Identification of HEV serotypes in clinical cases is important for monitoring emergence of more pathogenic variants, epidemiological surveillance and investigating sources of infection. Serotype identification is currently problematic following the widespread adoption of polymerase chain reaction (PCR)-based methods for HEV detection in place of virus culture. OBJECTIVES: To develop a reliable, sensitive method to identify species A and B serotypes directly from cerebrospinal fluid (CSF) specimens. STUDY DESIGN: A nested-PCR was used to amplify VP1 region sequences of HEV species A and B, that enabled unambiguous serotype identification by comparison with reference strains. RESULTS: 62 from 64 diagnostic CSF samples collected over a 19-month study period were successfully amplified (97% sensitivity), compared with 9/22 (41%) identified by virus culture of co-referred faecal and throat swab samples. Among these, 60 samples contained species B and 2 samples contained species A serotypes (coxsackievirus A6 and enterovirus 71) were identified. Rapid changes in serotype frequencies and diversity were observed; echovirus (E) type 9 infections predominated in early 2007, to be replaced by E30 later in the year and followed by a diverse range of eight different species B serotypes in 2008. CONCLUSIONS: The availability of a simple and rapid method for identification of serotypes and individual HEV strains or clusters directly from CSF will be of substantial value in surveillance, understanding more about serotype-associated differences in disease and monitoring the global spread of pathogenic variants such as enterovirus 71.