High prevalence of human rhinovirus C infection in Thai children with acute lower respiratory tract disease.

OBJECTIVE To determine the prevalence of human rhinoviruses (HRV) infections in children with lower respiratory disease in Thailand and monitor the association between species of HRV and clinical presentation in hospitalized paediatric patients. METHOD Two hundred and eighty-nine nasopharyngeal (NP) suction specimens were collected from hospitalized paediatric patients admitted to King Chulalongkorn Memorial Hospital, Thailand during February 2006-2007. Nucleic acids were extracted from each sample with subsequent amplification of VP4/2 by semi-nested RT-PCR for HRV detection. Other viral respiratory pathogens were also detected by PCR, RT-PCR or real time PCR. Nucleotide sequences of the VP4 region were used for genotyping and phylogenetic tree construction. RESULT In total, 87 of 289 specimens were positive for HRV indicating an annual prevalence of 30%. Wheezing or asthma exacerbation was the most common clinical presentation observed in infected patients. Sequence analysis and phylogenetic tree showed that 29 (33%) and 8 (9%) specimens belonged to HRV-A and HRV-B, respectively. Most of the HRV positive samples were HRV-C (58%). Moreover, species C was predominantly found in the paediatric population of Thailand in raining season (p<0.05). The frequency of co-infection of HRV-C with other respiratory viral pathogens was approximately 40%. CONCLUSION HRV-C represents the predominant species and is one of the etiologic agents in acute lower respiratory tract infection, causes of wheezing and asthma exacerbation in infants and young children in Thailand.