WSN/33 in Swine in the United States and Canada?
Recombinomics Commentary
April 28, 2005
>> the only viruses isolated were 27 H1N2 influenza A viruses which were found to be similar to avian-human-swine triple reassortants circulating in US pig populations <<
The above comment was from the WHO announcement concerning their inability to prove that the WSN/33 Korean swine sequences did not exist and were due to lab error. After failing to find or offer such proof, WHO cited the only positive data they could generate in the five month investigation. The investigation seemed to focus on gathering evidence to support the WHO speculation that the WSN/33 sequences at GenBank were related to a disputed shipment of WSN/33 to Korea.
Finding H1N2 in a few pigs in one of two farms in Korea did little to address the presence or absence of WSN/33. The sequences at GenBank were clearly from WSN/33, and the H1N2 sequences in swine in the US and Korea were not closely related to WSN/33.
New data has indicated that WSN/33 sequences are in the lungs of fatally infected pigs in Korea. It is unlikely that the samples containing H1N2 came from dead pigs because H1N2 rarely kills pigs and no WSN/33 was reportedly found. The finding of H1N2 in Korean pigs was not a surprise because H1N2 had been previously reported in Korean swine (A/Swine/Korea/CY02/02(H1N2)), and Korea imports pigs from the United States and Canada.
However, the finding of WSN/33 sequences in Korean pigs raises questions about the origin of these sequences. Since it appears that H1N2 arrived in Korea via pigs imported from North America, did WSN/33 in pigs arrive in Korea via North American pigs as well?