The intensity of influenza activity remains low with sporadic influenza activity reported in the United Kingdom

Summary: The influenza activity in Europe remains at baseline levels. Sporadic laboratory confirmed cases of influenza were detected in United Kingdom and Slovenia in week 45/2005. Seven influenza virus isolates were reported of which five were influenza A and two were influenza B. No confirmed cases of humans infected with the avian influenza A(H5N1) virus have been reported in Europe.

Epidemiological situation – week 45/2005: All countries reported a low intensity of influenza activity. Five countries (Denmark, England, Hungary, Lithuania and Slovakia) reported an increase in clinical activity compared to week 44/2005, but the incidence of influenza-like illness was low and at baseline levels.

For the geographical spread of influenza, England and Scotland reported sporadic influenza activity, which means that isolated cases of laboratory confirmed influenza infection have been found. 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 45/2005: The total number of respiratory specimens collected by sentinel physicians in week 45/2005 was 267, of which none were influenza virus positive. In addition, 850 non-sentinel specimens (e.g. specimens collected in hospitals) were analysed and seven tested positive for influenza virus: one influenza A(H3N2) in Slovenia, three influenza A (one A(H3), two A unsubtyped) in Scotland and one A(H3N2) and two B in England. None of the countries reported a dominant virus type.

Virological situation - 2005-2006 season (week 40-45/2005): Based on (sub)typing data of all influenza virus detections up to week 45/2005 (N=26; sentinel and non-sentinel data), 12 (46%) were influenza A (not subtyped), five (19%) were A(H3) of which two were A(H3N2), one (4%) was A(H1N1) and eight (31%) were B. Only the hemagglutinin of the influenza A(H1N1) virus from Switzerland was antigenically and genetically characterised being A/New Caledonia/20/99 (H1N1)-like (click here).

Up to week 45/2005 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 only been found sporadically since week 40/2005 in the Czech Republic, England, Estonia, Poland, Scotland, Slovenia and Switzerland. As all types and subtypes of influenza viruses that have circulated last season have been detected (click here) it remains to be seen which virus type or subtype will become dominant in Europe this season. While the influenza activity in Europe remains low, a small increase of respiratory syncytial virus (RSV) detections was reported by Ireland and Sweden.

Background: The Weekly Electronic Bulletin presents and comments influenza activity in the 31 European countries that are members of EISS. In week 45/2005, 26 countries reported clinical data and 25 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.