Sunday, July 24, 2005

Fatalities in Sichuan Linked to H5N1 Bird Flu Migration?

Recombinomics Commentary
July 24, 2005

The Chinese news Web site Sina.com reported Saturday the people infected had symptoms like fever, lack of energy, vomiting, bleeding from blood vessels beneath the skin, and shock.....

Animal viruses are also being scrutinized because of bird flu fears.

The above comments are from an AP story on the mysterious deaths of farmers in several villages near Ziyang in Sichuan province southeast of Chengdu. The wire report describes 20 patients with symptoms. Nine have died and 6 more are in critical condition. Only one patient ahs been discharged. The patients had been admitted between June 24 and July 21, so the delay in a diagnosis is cause for concern. Earlier reports also describe patients as being dizzy which lead to coma in some cases. These descriptions sound similar to a t least one death in Thailand after slaughtering a wild boar in May. There was no diagnosis in that cluster of cases either.

The proximity of both sets of cases to H5N1 outbreaks is cause for heightened concern. The 1918 pandemic had many mis-diagnosed cases, including those with neurological complications. H5N1 has been shown to be neurotropic in the lab, and variants with the PB2 polymorphism E627K have been isolated from mouse brains from isolates in Hong Kong as well as duck meat imported to Japan from Shandiong.

The E627K polymorphism is found in all human influenza A isolates, but is rarely detected in avian influenza. However, all H5N1 isolates from Qinghai Lake had E627K, signally possible neurological complications in humans infected with H5N1 with this polymorphisms. The polymorphism has been found in H5N1 isolates infected in 1997 in Hong Kong as well as 2004 in Vietnam and Thailand. Most of the isolates from tigers at the Sri Racha tiger zoo also had the change and the tigers had neurological symptoms before they died. Many H5N1 isolates from swine also have the E627K polymorphism.

Ziyang is just southeast of Chengdu which is about 400 miles southeast of Qinghai Lake. Some boxun reports have indicated bird flu is widespread in Qinghai province which is adjacent to Sichuan Province. Hong Kong radio reports indicate villagers in Sichuan say the deaths are being under-reprted. Boxun reports have also indicated China has isolated 10 distinct H5N1 variants and most can infect humans.

The sequence of H5N1 from Qingahi has been released and analysis indicates that several of the H5N1 polymorphisms that had previously been found only in isolates from Vietnam and Thailand are also in the isolates from Qinghai. Qinghai isolates have also acquired other polymorphisms normally found in mammalian isolates, such as the E627K polymorphism described above. The Qingahi isolates also has polymorhisms commonly found in migratory birds including polymorphisms linked to European isolates. Similar European polymorphisms have been found in isolates form Primorie and Chany Lake reserves in Russia, where over 500 bird have died recently.

As birds at Qingahi Lake and nature reserves in Russia begin to migrate to the south, west, and east, there is concern that such a migration might lead to a catastrophic spread of H5N1.

Human deaths in the adjacent province of Sichuan may indicate that such spread has already begun.

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