Tests in monkeys, mice and ferrets show that the swine flu thrives in greater numbers all over the respiratory system, including the lungs, and causes lesions, instead of staying in the head like seasonal flu.
In addition, blood tests show that many survivors of the 1918 flu pandemic seem to have immunity to the current swine flu, but not to the seasonal flu that hits every year.
Those were findings from a study by a top University of Wisconsin flu researcher that was released Monday and will be published in the journal Nature.
The researcher, Yoshihiro Kawaoka, said he is more concerned about swine flu because of these results.
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