Mild to moderate influenza activity in Europe and the detection of novel A(H1N2) and B viruses during the winter of 2001-02

Abstract

Influenza activity in Europe during the 2001-02 influenza season was mild to moderate. Compared to historical data, the intensity was low in six countries, medium in eleven and high in one country (Spain). The dominant virus circulating in Europe was influenza A(H3N2). Two novel influenza virus strains were isolated during the 2001-02 season: influenza A(H1N2) viruses (mainly isolated in the United Kingdom and Ireland, but also in Belgium, France, Germany, the Netherlands, Portugal, Sweden, Switzerland and Romania), and influenza B viruses belonging to the B/Victoria/2/87 lineage (mainly isolated in Germany, but also sporadically in France, Italy, the Netherlands and Norway). With the exception of H1N2 virus detections in England, and Ireland and the influenza B viruses belonging to the B/Victoria/2/87 lineage in Germany, these two viruses did not circulate widely in Europe and did not play an important role in influenza activity during the 2001-02 season. An influenza B virus belonging to the B/Victoria/2/87 lineage will be included in the 2002-03 influenza vaccine. The new subtype influenza A(H1N2) is covered by the 2002-03 vaccine, as the haemagglutinin and neuraminidase components of the H1N2 viruses are antigenically similar to the vaccine components (H1N1 and H3N2).

Amantadine Resistance among Porcine H1N1, H1N2, and H3N2 Influenza A Viruses Isolated in Germany between 1981 and 2001

“…At present, H1N1, H1N2, and H3N2 subtypes of infl uenza A viruses are circulating in Europe [4,5] . All three subtypes have also been isolated from pigs showing clinical symptoms during different outbreaks in Germany between 1981 and 2001 [6,7] .…”

“…Only aquatic birds permit replication of all known infl uenza A virus subtypes (H1-16, N1-9). H1N1, H1N2, and H3N2 subtypes are circulating in the human population of Europe [4,5] . The same subtypes were isolated from swine in Germany [6,7] .…”

Changes in the hemagglutinins and neuraminidases of human influenza B viruses isolated in Italy during the 2001–02, 2002–03, and 2003–04 seasons

“…Throughout the last decade, Yamagata-lineage viruses were the predominant B viruses circulating worldwide. During the 2001-02 influenza season, Victoria-lineage viruses reappeared for the first time in 10 years in North America and Europe [Paget et al, 2002].…”

Cocirculation and Evolution of Two Lineages of Influenza B Viruses in Europe and Israel in the 2001-2002 Season

“…The reassortment between two lineages of influenza B viruses has been reported previously (6,16), and it is thought that such influenza reassortants have selective advantages in viral growth, replication, or stability. The pattern of spreading of B/Hong Kong/1351/02-like viruses in our study and others (10) In recent years, molecular methods have been developed and successfully applied in the diagnosis and surveillance of influenza viruses (3). Here, we employed a high-throughput molecular method combining RT-PCR and DNA sequencing, which provides an alternative to the classical hemagglutinin inhibition assay with specific antisera for determining the phylogenetic relationship of influenza virus isolates.…”