Human Flu Sequences in Chinese Swine
Recombinomics Commentary
September 29, 2007
Chinese swine sequences being released at Genbank are not from a natural infection. Either the lab has submitted serious sequencing errors or Chinese swine have been infected with a seriously flawed vaccine. The sequences in question come from isolate A/swine/Shandong3/2005(H3N2). Seven of the eight gene segments are human, and one (NS) is swine. Although human sequences have been found previously in swine, one of the human sequences (PB2) is virtually identical to the 1934 sequence, A/Puerto Rico/8/34, is used in seasonal flu vaccines. Although PR-8 genes have been seen previously in animals injected with a vaccine that was not completely killed, these animals had all six of the vaccine genes from 1934. The killed recombinant vaccines have H and N from the virus of interest, and the other six genes are used to grow the recombinant to high levels. The six human genes, other than PB2, are closely related to human seasonal flu from the late 1990’s including the vaccine strain A/Moscow/10/99(H3N2). However, in that vaccine only the H and N are from the 1999 human isolate.
The recent sequences were from 2005 isolates from swine lung. In 2005 reports of pig disease in China were widely reported. It remains unclear if the isolate described above was the cause of some or most of the outbreaks, or was the result of some immunization program designed to protect against the outbreak.
The recently released sequences however, are not natural, and more information on the isolates and sequences would be useful,
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