More Migration of Qinghai H5N1 into Ghana
Recombinomics Commentary
May 22, 2007
This would confirm Ghana's claim that the virus was of a regional
and possibly illegal commercial origin and not due to migratory
birds. - Mod.MHJ
The above Promed commentary under the “Avian influenza, poultry vs migratory birds” thread continues the distorted personal opinions on the spread of Qinghai H5N1 by migratory birds. This thread began in February, 2006, when H5N1 was detcted in Nigeria. However, in August, 2005 it was clear that migratory birds were transporting and transmitting H5N1. It is unfortunate that news and commentaries by a scientific organization targeting infectious disease continues to carry such gross distortions to a broad readership that lacks the background to understand the evolution of H5N1 avian influenza.
The latest commentary above is in response to the OIE report indicating that the outbreak in Ghana involved the Qinghai strain of H5N1 with geographic markers for western Africa, as expected for introductions by migratory birds in the area. The Ghana outbreak, confirmed earlier this month, follows the same pattern seen in neighboring countries, and in all countries west of China. All reported Qinghai H5N1 infections after the Qinghai strain was identified at Qinghai Lake in May, 2005.
Prior to the outbreak at the nature reserve, no “Asian” H5N1 had been reported in any country west of China, even though H5N1 was first detected in Guangdong Province in 1996. No trade or smuggling led to a reported H5N1 outbreak west of China. The first outbreak west of China was in the summer of 2005 at Chaney Lake in Siberia, followed by Erhel Lake in Mongolia. These outbreaks were also due to the Qinghai strain of H5N1, removing any doubt about the role of migratory birds in the spread of this strain. However, it was at this time that Promed began its propaganda campaign. The latest commentary, quoted above, cited confirmation of the Promed misleading commentaries on transportation and transmission of H5N1 by migratory birds.
As expected, the sequences of the isolates in Ghana were the Qinghai strain of H5N1. They were most closely related to the Qinghai isolates in neighboring Ivory Coast. NAMRU-3 sequenced the H and N from three chickens. All three sequences were identical and differed from the Ivory Coast turkey sequences at 7 positions in HA and 4 positions in NA. This level of heterogeneity would be expected if the Ghana sequences were introduced by migratory birds.
Sequences from the turkeys in the Ivory Coast would be closer, as was seen in turkey sequences in England, relative to the goose sequences in Hungary, which were 99.96% identical. There have been no reports of sequences in neighboring countries that were 99.96% identical to the Ghana sequences. Instead the OIE report from France indicated that the sequences were in the 98.8-99.6% range, as expected if introduced by migratory birds.
As was seen in other countries west of China, the Qinghai sequences this season were more evolved than last season, signaling new acquisitions via recombination with H5N1 carries by migratory birds. These types of changes were seen in the Ghana sequences. One of the four changes in the NA sequence was G743A, which was also seen in recent isolates (six) from Egypt, which involved four different Qinghai genetic backgrounds, as well as isolates (two) in Moscow, which was yet another backgrounds. Thus there were 11 recent 2007 Qinghai isolates representing six different genetic backgrounds in three different countries, which had the same change at the same time, strongly implicating migratory birds as the donor.
Poultry was an unlikely source. All of the isolates in Russia, Egypt, and Ghana were chickens. Infections by traded chickens are unlikely, since Qinghai H5N1 causes sudden death in chickens. Moreover, in spite of the title in the Promed series, there is little evidence of long range transmission of H5N1 by trade. Although H5N1 has been reported in China since 1996, no H5N1 in poultry was reported in any country west of China until after the Qinghai outbreak at Qinghai Lake. H5N1 was discovered in smuggled birds on a Belgium airplane from Thailand, but those isolates were Clade 1, which has never been reported in poultry or patients outside of southeast Asia. Similarly, H5N1 was detected in quarantined exotic birds in England, but those isolates were the Fujian Clade 2.3 isolates, which have also never been reported in poultry or people in any country west of China.
All H5N1 in poultry or people west of China has been the Clade 2.2 Qinghai strain. There have been multiple sub-clades of Clade 2.2 due to regional markers, as seen in western Africa, including the Ghana isolates, but those sub-cades are due to independent introductions of Qinghai sub-clades by migratory birds. The same type of sub-clades are seen in the recent Isolates in Egypt, but those isolates, like the isolates from last season have the regional markers found in Egypt, Israel, Gaza, and Djibouti.
Thus, the report on the Ghana sequences by OIE in France confirmed the H and N sequences generated by NAMRU-3 earlier, and supports an introduction of H5N1 into Ghana by migratory birds carrying sub-clades of Qinghai H5N1 with West African region markers. There has been no evidence disclosed that is not consistent with introductions by migratory birds carrying Qinghai H5N1.
Today a second area was confirmed to be infected by H5N1 in Ghana. It is likely that these sequences will be distinct from the earlier Ghana isolates, but the sequences will be Qinghai with West African regional markers and will have been introduced into central Ghana by migratory birds.
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