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Commentary

Worldwide Wild Bird Transport and Transmission of Qinghai H5N1
Recombinomics Commentary
December 5,  2006

While the virus mostly spread in Asia through the poultry trade, almost all of the spread throughout Europe was due to migratory birds and both poultry and wild birds carried it into and across Africa, they concluded.
Some outbreaks are more difficult to explain.

"H5N1 outbreaks in South Korea, Russia, Mongolia, Nigeria, India, Pakistan, and Cameroon were inconsistent with both reported poultry trade (no poultry imports were reported from H5N1-infected countries) and the timing and direction of migratory bird travel in the month of the outbreaks," the researchers wrote.

While the virus mostly spread in Asia through the poultry trade, almost all of the spread throughout Europe was due to migratory birds and both poultry and wild birds carried it into and across Africa, they concluded.
Some outbreaks are more difficult to explain.

"H5N1 outbreaks in South Korea, Russia, Mongolia, Nigeria, India, Pakistan, and Cameroon were inconsistent with both reported poultry trade (no poultry imports were reported from H5N1-infected countries) and the timing and direction of migratory bird travel in the month of the outbreaks," the researchers wrote.

Use of the "month of the outbreaks" for correlation between wild bird migration and H5N1 introductions is naive at best, and clearly misleading.  These misleading statements have been link to several wildlife conservation groups, and continue to generate confusion.

All countries listed above as "more difficult to explain" have Qinghai H5N1 and are clearly linked to the transport and transmission of H5N1 by wild birds.  This mode of spread has been obvious since August of 2005, and these repeated reports questioning the linkage to countries with Qinghai H5N1 creates additional credibility issues, which ironically are largely linked to H5N1 OIE filings, which also have significant credibility issues.

The Qinghai strain of H5N1 was first reported in a massive die-off of long range migratory birds at Qinghai Lake in May of 2005.  Although H5N1 death of 189 birds was initially denied, infections of 519 birds were acknowledged a few days later in an OIE report of H5N1 infections in several species including bar headed geese.  The number of dead birds quickly rose to more than 6000 and the large number of deaths signaled a major change in the transmission of H5N1. 

The presence of the lethal strain in birds that could fly 1000 miles in 24 hours created concern, although it was possible that Qinghai H5N1 would burn itself out.  However, the large number of birds at the reserve, coupled with the species diversity, suggested H5N1 would spread from the lake, and that spread would include Chany Lake in southern Siberia, where many of the long rang birds spent the summer.

In June H5N1 outbreaks were reported in northwestern China in domestic waterfowl signaling movement toward southern Siberia.  This movement was confirmed in mid-July and early August when H5N1 was reported in several farms adjacent to Chany Lake, as well as in adjacent Kazakhstan and Mongolia.  None of these countries had previously reported H5N1 infections.

In July the H5N1 from Qinghai Lake was sequenced.  The strain had a novel cleavage site, GERRRKKR, as well as a mammalian PB2 polymorphism, E627K.  The 8 gene segments were readily distinct from prior H5N1 in Asia, although there were regions of identity with H5N1 from Shantou in southeastern China as well as South Korea/Japan isolates.  Other sequences matched isolates from Europe and low path H5 in southeast Asia, indicating the H5N1 was a novel recombinant that war easily distinguished from previously reported isolates.  Moreover, H5N1 infections were also linked to fatal infections of waterfowl, which was another distinguishing characteristic.

Therefore, when sequence data was released on H5N1 from Chany Lake, there was no doubt that Qinghai H5N1 was being transmitted and transported by migratory birds (see dynamic map).

These reports were accompanied by a series of reports from bird conservation groups.  These reports included statements that the wild birds were victims, and "dead birds don't fly" comments.  These statements were carried by Promed, which also began a series on the role of trade and wild birds in the spread of H5N1.  The reports suggested that H5N1 had not been found in live wild birds, and infection of domestic poultry somehow selected for a novel version of H5N1, which could then kill wild birds.  However, the sequence of H5N1 from a healthy crested grebe was virtually identical to the H5N1 from poultry infected with the Qinghai strain.

The H5N1 was being transported from one nature reserve to another.  In Mongolia, dead bar head geese and whooper swans were identified at Erhel Lake.  Wildlife groups assisted in collecting samples.  Comments initially indicated that the deaths could not be due to H5N1, because the number of dead birds was not high.  When the birds were H5 positive, they were predicted to not be H5N1 because not enough birds were dead.  When the birds were H5N1 positive and the sequence matched the Qinghai strain, attention shifted to Europe.

The birds in the Chany Lake region were expected to migrate southwest, through eastern Europe, the Middle East East and into western Africa.  Initial reports describe H5N1 in the Volga Delta in August, 2005.  However these reports were denied and other cause of waterfowl deaths were cited.

 In October, 2005 H5N1 was confirmed in the Danube Delta in Romania, as well as western Turkey.  However, neighboring countries denied that the waterfowl deaths were due to to H5N1.  Many countries in the area filed OIE reports on Newcastle Disease infections.  Media reports from Romania indicated swans had been dying since August.  Although the waterfowl in the Danube and Volga Delta in August would be migrating to the south in the fall, countries in the area continued to deny H5N1 in waterfowl deaths.  Wildlife conservation groups issued statements that wild birds were not a major source of H5N1 because widespread infections in Europe failed to materialize.

However, when patients began dying in eastern Turkey in January, 2006, countries began to acknowledge H5N1 infections.  Turkey had denied infections in the east, but subsequently acknowledged that H5N1 had been found in eastern Turkey in November and December, prior to acknowledgment of widespread infections in January.  However, many countries continued to deny H5N1 infections until patients in neighboring Iraq, Azerbaijan, and Egypt began to die in February.  Many countries in Europe, the Middle East, and Africa then began to report H5N1.

When Nigeria reported H5N1 infections in poultry, conservation groups again cited trade because H5N1 had not been reported in Egypt and birds migrating to Nigeria would have passed through Egypt.  Within a few days however, Egypt did report H5N1 outbreaks.  Moreover, Egypt recently released Qinghai H5N1 sequences isolated from a teal in December, 2005.  Moreover, sequence data from Nigeria indicated the H5N1 was due to independent introductions, consistent with wild bird sources.  These independent introductions were subsequently found for neighbor countries, including Niger, Ivory Coast, Burkino Faso.

In all of these cases, there were no reported H5N1 infections prior to the summer of 2005.  All of the reported outbreaks were linked to the Qinghai strain.  Although H5N1 has been reported in Asia since 1996, there were no reports of H5N1 in countries west of China until the 2005 infections after the Qinghai Lake outbreak.  In eastern Asia, where most H5N1 infections were reported, only one H5N1 Qinghai isolate has been reported.  It was in a guinea fowl in Shantou in 2006.  The other 405 H5N1 isolates from eastern China, largely isolated from wet markets in 2005 and 2006, were not the Qinghai strain.

All of the countries "most difficult to explain" have recent Qinghai infections.  Reliance on OIE report dates for introductions of H5N1 into a country is unrealistic.  Data continues to accumulate to show that these reports are significantly delayed.  All of the H5N1 introduced into these countries is the Qinghai strain, and the main driver of transport and transmission is wild migratory birds.

In June dead geese were reported on a farm on Prince Edward Island.  They had Qinghai H5N1 symptoms and died suddenly.  One was tested and was H5 PCR confirmed.  The sample was held for almost two weeks on PEI before it was shipped to Winnipeg for confirmation of the confirmation.  The sample degraded and H5 was not reconfirmed.  The size of the insert was withheld, although all evidence suggested the deaths were due to Qinghai H5N1.  The frequency of avian influenza infections in dead and live birds on PEI remains high, but the number of dead birds tested in Canada and the United States remains low.  In the United States, 45,000 live or hunter killed birds have been tested, but the number fo dead or dying birds tested is below 1000 (updated table is just over 1000).  H5N1 is almost always found in dead or dying birds prior to detection in healthy birds.  Although low path H5N1 has been found in the 45,000 tests on live birds, low path has not been reported in dead birds because of limited testing.  Birds in North America have Asian sequences and H5N1 Qinghai isolates have North American sequences.

Wild birds remain the primary source of transport and transmission of H5N1.

Limited testing of dead birds in North America signals a fatally flawed H5N1 surveillance program, which largely ignores dead and dying wild birds.

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