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H5 Wild Bird Flu Confirmed in Mongolia
Recombinomics Commentary
August 18, 2005
"We found it was H5 influenza," Karesh told Reuters in a telephone interview.
But only about 100 of the 6,500 birds on the lake, representing 55 different species, had died, he added.
"Sure enough, birds were dying," Karesh said. They sampled some of the dead swans, geese and gulls, and also collected samples from healthy birds.
But the jury is out on wild birds as being major spreaders of the virus, Karesh said.
The above comments confirm that H5 wild bird flu has been detected in Mongolia. In the initial OIE report, only influenza A was noted. It seems likely that the H5 in Mongolia will be closely related to the H5N1 at Qinghai Lake, Chany Lake, and across southern Siberia (see map).
In the past H5N2 and H5N3 have been isolated from Chany Lake and Primorie in southern Russia. However, the earlier isolates were low pathogenicity and the HA cleave site was a typical LPAI site. In contrast the all sequences reported for H5N1 from Qinghai Lake and Chany Lake were HPAI. Usually waterfowl are resistant to H5N1. In Vietnam 70% of the ducks in the Mekong Delta are H5N1 positive, but they are asymptomatic. The H5N1 that migrated form Qinghai Lake to Chany Lake to the Urals could kill domestic ducks and geese. However, the WHO report indicated the infections were via common drinking water and ducks can more easily pollute a small pond than a large lake.
At Qinghai Lake the die off was said to be without precedent with over 6000 birds dying. However, the vast majority of the dead birds were bar headed geese, so the frequency of death was markedly lower for other species even though four other species were cited in the Qinghai OIE report. The species listed above are similar to those that died at Qinghai lake, but the transmission route clearly shows that the H5N1 was moved by migratory birds, The sequences of H5N1 at Qinghai Lake and Chany lake are very closely related, and the extension of the die-off across southern Siberia and northern Kazakhstan matched the migratory path of birds across sparsely populated regions, especially in Kazakhstan,
The migration period is just beginning for Qinghai Lake and Chany Lake, so the number of H5N1 infections should increase as migratory birds move H5N1 across Asia, Europe, and beyond.
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