The intensity of influenza activity in Europe remains low
Summary: Influenza activity in Europe remains at baseline levels. Sporadic laboratory confirmed cases of influenza were detected in the Czech Republic, Portugal, Scotland and Sweden in week 46/2005. Six influenza virus isolates were reported of which five were influenza A and one was influenza B. No human cases of influenza A(H5N1) virus have been reported in Europe. Laboratory reports of respiratory syncytial virus are increasing in various countries.

Epidemiological situation – week 46/2005: All countries reported a low intensity of influenza activity in week 46/2005. Two countries (Latvia, Lithuania) and three regions (England North, France North East and France South West) reported an increase in clinical activity compared to week 45/2005, but the incidence of influenza-like illness was low and at baseline levels.

For the geographical spread of influenza, France, Scotland and Switzerland reported sporadic influenza activity, which means that isolated cases of laboratory confirmed influenza infection have been detected. All other countries reported no influenza activity, meaning that the overall level of clinical activity remained at baseline levels and influenza virus infections are not being laboratory confirmed.

Definitions for the epidemiological indicators can be found here.

Virological situation - week 46/2005: The total number of respiratory specimens collected by sentinel physicians in week 46/2005 was 282, of which one was positive for influenza A virus in the Czech Republic. In addition, 1181 non-sentinel specimens (e.g. specimens collected in hospitals) were analysed and six tested positive for influenza virus: three influenza A(H3N2) in Sweden, two A unsubtyped in Scotland and one B in Portugal. Two countries reported dominant subtypes: influenza B in Switzerland and influenza A(H3N2) in Sweden.

Virological situation - 2005-2006 season (week 40-46/2005): Based on (sub)typing data of all influenza virus detections up to week 46/2005 (N=38; sentinel and non-sentinel data), 15 (39%) were influenza A (not subtyped), nine (24%) were A(H3) of which five were A(H3N2), one (3%) was A(H1N1) and 13 (34%) were influenza B. Based on the characterisation data of all influenza virus detections up to week 46/2005, six have been antigenically and/or genetically characterized: four A(H3) A/Califormia/7/2004 (H3N2)-like, one B/Shanghai/10/2003-like and one A/New Caledonia/20/99 (H1N1)-like. (click here).

Up to week 46/2005 no human cases of A(H5N1) influenza have been reported in Europe.

Comment: Influenza activity in Europe remains at baseline levels. Laboratory confirmed cases of influenza have been found sporadically throughout Europe so far this season: in the Czech Republic, England, Estonia, France, Poland, Portugal, Scotland, Slovenia, Sweden, Switzerland and Wales. As all the types and subtypes of influenza viruses that circulated last season have been detected (click here) it remains to be seen which virus will become dominant. While the influenza activity in Europe remains low, increases of respiratory syncytial virus (RSV) detections were reported by various countries (England, Estonia, France (click here), Ireland, Latvia, Luxembourg and Sweden).

Background: The Weekly Electronic Bulletin presents and comments influenza activity in 28 European countries. In week 46/2005, 24 countries reported clinical data and 23 countries reported virological data to EISS. The spread of influenza virus strains and their epidemiological impact in Europe is being carefully monitored by EISS in collaboration with the WHO Collaborating Centre in London, UK.

Other bulletins: To view national/regional bulletins in Europe and other bulletins from around the world, please click here. For a global update on the influenza A(H5N1) situation, please click here.