Abkhazia Institute for Social and Economic Research

The Ministry of Health in Viet Nam has confirmed two new human cases of influenza A(H5N1) virus infection, the first human cases to have been reported from Viet Nam since November 2005. Both cases have been confirmed by the National Institute of Hygiene and Epidemiology (NIHE) and by the WHO H5 Reference Laboratory, US Centers for Disease Control and Prevention (CDC).

Further to the reoccurrence of highly pathogenic avian influenza virus subtype H5N1 in wild birds, Germany sequence data of the hemagglutinin genes of 2 isolates obtained from infected mute swans found at Nuremberg, Bavaria, and Frohburg, Saxonia have now been generated at the Friedrich-Loeffler Institut, Isle of Riems.

Preliminary comparisons and database searches demonstrated that these 2 sequences are closely related (at least 99.5 per cent identity) but distinguishable from each other. Other closely related sequences which are
publicly available originate from H5N1 isolates made in 2006 from grebes (_Podiceps spec._) in southern Siberia and from a whooper swan (_Cygnus cygnus_) and a common goldeneye (_Bucephala clangula_) in Mongolia. In a
phylogenetic analysis, these viruses form a separate cluster with H5N1 viruses isolated from chickens in Afghanistan. In addition, viruses from the Russian Krasnodar region and a virus detected in 2007 in Abkhazia (breakaway province of Georgia) in a mute swan in Italy are associated with this cluster.

In a joint analysis performed with the Community Reference Laboratory at VLA, Weybridge, the H5N1 virus from the outbreak in a turkey holding in the Czech Republic appears to be equidistant yet closely related (99.2 per cent identity) to those from Nuremberg and Frohburg.

Intensified monitoring among wild birds and molecular analysis of further virus isolates should shed more light on the possible routes of introduction and spread of these viruses in Central Europe.