Surprising Migration of Qinghai H5N1 To England
Recombinomics Commentary
February 4, 2007
But the outbreak at a Suffolk farm has come as a surprise.
Migrating birds don't come to the UK for a month or two. So the priority for government scientists is to trace how the virus got here.
The most likely explanation is that it was from a wild bird arriving earlier than expected.
The above comments suggest that the H5N1 in England was due to migratory birds arriving surprisingly early. Last year, the same type of “surprises” were reported throughout Europe, as country after country reported H5N1 infections in January and February. In 2006 the "surprising" movements were said to be due to wind and climate changes. The repeated "surprises" however, overlook the obvious, which are poor surveillance programs that only detect H5N1 when wild or domestic birds began to die in unexpected numbers or in unexpected places.
All of the H5N1 detected in Europe, beginning in the fall of 2005, has been the Qinghai strain (Clade 2.2). The introductions follow migratory bird flyways and many countries in Europe have only found H5N1 in wild birds. Those with poor surveillance find H5N1 in domestic poultry after the domestic birds have been infected with H5N1 from the wild birds. H5N1 can infect many avian species, so the introduction of H5N1 by the long range migratory birds leads to additional infections in resident wild and domestic birds.
Last year the surveillance system in England identified one bird with H5N1, a swan that washed ashore in Scotland. A dead bird floating into Scotland signaled additional H5N1 flying into England, as well as countries throughout western Europe. However, many, including England, claimed to be H5N1 free.
Last season’s events have been repeated this season. Most countries in Europe again claim to be H5N1 free. Recently, H5N1 was confirmed in Hungary and Krasnodar, signaling H5N1’s presence, but neighboring countries continue to fail to detect or report H5N1.
When domestic poultry is infected in numbers that can no longer be denied, the “surprising” discoveries are announced. These surprises became old last season, and a repeat this season again raises questions on surveillance and transparency in the region.
The lack of transparency is compounded by the hoarding of the H5N1 sequences in the WHO private database at Los Alamos. The largest hoarder is the same lab located in Weybridge, England, that confirmed the recent outbreaks in Hungary and England. This WHO affiliated lab gets samples from Europe and the Middle East that are suspected to be H5N1 positive. A May, 2006 presentation indicated over 700 birds in Europe were positive for highly pathogenic H5N1. All had the Qinghai strain and sequences from about 80 of the birds or mammals were displayed in an HA phylogenetic tree here and here. Included in the list were isolates from Slovakia, Ukraine, Austria, Czech Republic, Greece, France, Bulgaria, Turkey, Azerbaijan, Bosnia, Denmark, Serbia, Croatia, Germany, Romania, Poland, and Albania.
Although the sequences had been generated prior to the Weybridge lab's presentaion in May 2006, the only bird sequence that has been released has been from a turkey in Turkey in October, 2005. Although promises of release of the data have been made for well over a year, this critical data is hidden in the WHO database and available to a handful of WHO affiliated labs. Others have released partial sequences from the vast majority of countries on the list, indicating the failure to release the data is firmly linked to the Weybridge lab generating the sequences.
Analysis of the limited number of sequences that have been released indicates that the H5N1 migrates from country to country, acquiring regional changes via recombination. These changes allow for the tracing of origins and also provide critical information in the diagnosis and treatment of birds and humans.
Changes in the sequences dictate the generation of new probes to detect the evolving H5N1. Failure to update probes creates false negatives. The sequences also help trace origins. Weybridge has released the HA sequences from two of the H7N3 infected chickens from last year, A/chicken/England/4054/2006(H7N3) and A/chicken/England/4266/2006(H7N3). These sequences had M230I, which is found in human influenza strains (H1N1, H3N2, influenza B). Recently, M230I was also found in H5N1 from the Gharbiya cluster in Egypt. These sequences were of interest because they were from the largest human cluster reported to date in Egypt, and the NA sequences from the cluster members had N294S, which confirms Tamiflu resistance. The coding for M230I in the Gharbiya cluster matched H5N1 in Asia. However, additional H5N1 infected birds in Egypt had M230I, and the coding matched the H7N3 from England. This association points toward dual infections involving H5N1 and H7N3 and the acquisition of M230I via recombination.
However, the distribution of HA M230I and NA N294S is not public, because the H5N1 sequences remain hidden in the WHO private database. As indicated in the December 2006 WHO report, the WHO consultants continue to describe the evolution of H5N1 as a series of random mutations. Consequently, they are constantly “surprised” by new sequences and migration patterns of H5N1.
The reporting failures and continued hoarding of the H5N1 data has moved beyond scandalous.
Media sources
Phylogenetic Trees