H5 Norfolk Restriction Expanded to Suffolk England
Recombinomics Commentary
November 12, 2007
In consultation with ornithologists and other experts, a wider Restricted Zone has been established in addition to the controls put in place earlier today; i.e. the 3 km Protection Zone and 10 km Surveillance Zone around the Infected Premises. The new Restricted Zone covers much of Norfolk and the whole of Suffolk.
The above announcement by DEFRA further supports media reports suggesting that the H5 infection in domestic poultry in Norfolk, England is Qinghai H5N1 imported via migratory birds. Today’s media reports included a description of symptoms which matched those of the Qinghai strain of H5N1. Moreover, the affected population was free range turkeys, ducks, and geese.
Although media reports indicated the initial positives were turkeys, it is likely that the turkeys were acutely affected because H5N1 frequently produces mild or no symptoms in waterfowl.
The zone was expanded after consultation with ornithologists, who would help define migration patterns of wild birds.
After the widespread outbreaks in Germany and neighboring countries over the summer, more detection of H5N1 in the fall was expected because migratory birds can mix with resident wild and domestic birds to spread the H5N1 further. Moreover, detection of H5N1 antibodies in domestic ducks provided additional evidence for viral interactions between wild and domestic birds.
The description of the sequences from H5N1 birds in Germany this summer were similar to the recent sequence from Krasnodar, which was the Qinghai strain of H5N1 and was most closely related to H5N1 detected in the massive Tyva/Mongolia outbreak in the spring of 2006.
The recent Krasnodar sequence has been publish, and like other H5N1 sequences in Russia, Egypt, and Ghana, the sequence had acquired NA G743A, suggesting a common source was interaction with local versions of Qinghai H5N1 resulting in the transmission of this marker.
The early detection of H5N1 in England this year suggests addition outbreaks will be reported in Europe in the near future.
Media Links
Recombinomics Presentations
Recombinomics Publications
Recombinomics Paper at Nature Precedings