Detection of influenza C virus in pediatric respiratory specimens by real-time PCR

Abstract

Respiratory infection is a major disease burden worldwide. Statistical reports revealed it is one of the main causes of mortality and morbidity especially in young children. Influenza infection is one of the predominant cause associate with respiratory infection. Traditionally, studies have been emphasized on the detection of influenza A and B virus owing to their significance in clinical and economic impact. Attention of influenza C virus is rarely recognized due to its difficulty in isolation. However, recently, increasing reports have been illustrated the co-circulation of influenza C virus globally. Serological studies also suggested majority of people worldwide acquired influenza C virus infection in their early childhood or adolescent stage, yet information regarding influenza C virus is still inadequate. Epidemiological and clinical impact of influenza C virus in pediatric patients in Hong Kong was examined by the approach of real-time PCR. From November 2007 to April 2011, a total of 1, 037 specimens were obtained from pediatric patients exhibited apparent respiratory tract illness in Hong Kong. Eleven strains of influenza C virus were detected by real-time PCR approach. All patients with influenza C virus infection were below 5 years of age with the youngest age of 11 months. The ratio of infection in male to female was approximately one to one. High grade fever appeared to be the most frequent clinical manifestations (10/11) of influenza C virus infection. Upper respiratory tract infection was also occasionally observed. The clinical presentation of influenza C virus was similar to its influenza counterpart. Phylogenetic analysis of influenza C virus was examined in 6/11 of the isolates to determine the lineages of co-circulating influenza C viruses in Hong Kong. Nucleotide sequencing was performed with primer targeting the hemagglutinin-esterase (HE) gene. Result revealed that most of the detected influenza C virus associate with the C/Sao Paulo/378/82 related lineage. Results from this study revealed the positive rate of influenza C was comparable to influenza B and resultant respiratory symptoms could be severe in pediatric patients It is suggested to consider the inclusion of influenza C virus detection in routine diagnostic panel and real-time PCR could be a desirable detection platform account for its sensitivity and rapidity.published_or_final_versionMicrobiologyMasterMaster of Medical Science