A farm worker came back from a visit to Mexico April 12 and went to on a farm two days later. This seems slightly odd to me, as every time I cross the border I’m asked if I have visited any farms in the last week. That should raise some caution about travelling between foreign countries and farms.
The swine on an Alberta farm have become ill with the Mexican swine flu (H1N1 subtype). That gives it another place to recombine and another pool to live in. We could have alternating epizootics and epidemics. Great.
Recombinomics blog adds:
Co-circulation of human and swine H1N1 provide significant opportunities for adaptation to the human host via recombination. Two polymorphisms are already fixed in seasonal flu, H274Y for Tamiflu resistance, and E627K in PB2 which allows the virus to more efficiently replicate at lower temperatures.
These changes can lead to adaptation in humans, as well antiviral resistance. Therefore, the evolution of the H1N1 over the summer will be closely monitored. The current H1N1 has already acquired tandem human H1N1 polymorphism in HA, which may have led to the species jump from swine to human.
Thus, the efficient transmission from swine to human and vice verse, raises concerns that further adaptation to humans can lead to a fall pandemic similar to 1918. The species jump indicates the virus can adapt to a new host, and additional acquisitions over the summer continue to be a cause for concern.