Genetic characterization of the hemagglutinin of two strains of influenza B virus co-circulated in Taiwan

Abstract

Two isolates of influenza B virus were obtained in the spring of 1997. One strain, B/Taiwan/21706/97, was isolated from a patient who had acute tonsillitis. The other, B/Taiwan/3143/97, was isolated from a patient who was diagnosed with meningoencephalitis. This implies that the influenza B viruses not only cause respiratory symptoms but may also cause inflammation of the nervous system. Sequence analysis of the hemagglutinin (HA) gene, HA1 domain, indicated that there were remarkable amino acid changes in the strain B/Taiwan/3143/97 compared to B/Victoria/2/87, B/Yamagata/16/88, and B/Taiwan/7/88. The changes in the positions 116, 200, 238, 242, and 271 were correlated with receptor binding. Furthermore, a potential glycosylation site at position 233 was lost. In total, 30 amino acid changes were noted at positions ranging from 116 to 295. These changes may affect the antigenicity of the virus. Phylogenetic analyses also showed that the B/Taiwan/3143/97 was located in an independent lineage, when compared to the reference strains belonging to B/Victoria/2/87 and B/Yamagata/16/88 lineages. This supports the hypothesis that influenza B viruses with distinct genetic characteristic were co-circulated in Taiwan.

Encephalitis Associated with Influenza B Virus Infection in 2 Children and a Review of the Literature

“…In the English-language literature, 21 cases of IBAE have been reported [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Eight cases were excluded from this analysis: 4 were reported in articles that contained insufficient information for analysis [15][16][17][18], 3 were reported in studies that failed to provide adequate serologic or cell culture-based evidence of influenza B virus infection [6,19], and one case may have been Reye syndrome [20].…”

“…Eight cases were excluded from this analysis: 4 were reported in articles that contained insufficient information for analysis [15][16][17][18], 3 were reported in studies that failed to provide adequate serologic or cell culture-based evidence of influenza B virus infection [6,19], and one case may have been Reye syndrome [20]. Therefore, including the 2 patients in this report, a total of 15 patients had cases that met clinical criteria for IBAE.…”

Multiplexed Flow Cytometric Immunoassay for Influenza Virus Detection and Differentiation

“…Over the past 20 years, influenza B viruses have caused frequent epidemics in humans, as have the H1 and H3 subtypes of influenza A viruses. Although influenza B viruses are generally considered less virulent than influenza A viruses, recent studies have demonstrated a substantial clinical impact attributable to influenza B viruses that were shown to cause severe respiratory symptoms as well as central nervous system diseases. − While there are also no antigenically distinguishable subtypes for influenza B viruses based on the surface antigens, two genetically and antigenically distinct lineages of influenza B viruses, represented by the reference strains B/Victoria/2/87 (Victoria) and B/Yamagata/16/1988 (Yamagata), have co-circulated in humans since at least 1983. − Recent advances in antiviral chemotherapy and the ever-present potential of pandemic influenza emphasize the importance of accurate and timely diagnostic techniques. − Moreover, influenza resembles many other respiratory diseases (such as severe acute respiratory syndrome, SARS) and infections caused by many biothreat agents (such as Bacillus anthracis , Yersinia pestis , Botulinum toxin, etc.) in initial symptoms (sudden onset of high fever, headache, muscle pain, severe malaise, etc.).…”