Pandemic Influenza: Could History Repeat Itself?
Recombinomics Commentary
January 24, 2005
The University of Michigan Symposium is being webcast live. A few issues came up this morning that might be a bit surprising.
There was quite a bit of emphasis on screening for human / avian reassortment in H5N1, although it was acknowledged that there have now been 4 outbreaks (Hong Kong, 1977; Hong Kong / Fujian Province, 2003; Thailand / Vietnam, 2004; Vietnam, 2005) resulting in fatal human infections, yet none involved reassortment between human and avian genes.
Epidemiological evidence was cited supporting tiger to tiger transmission in the Sri Racha Tiger Zoo in Thailand and feline to feline lab transmission was mentioned, but there was not data on pet infections of transmission. However, earlier reports indicated at least 3 fatal H5N1 pet infections in Ho Chi Minh City several weeks ago, along with collection of 200 pets for testing.
Similarly, no one at the conference has access to the new 2005 cases in Vietnam, so there was no sequence data on the stability of the virus.
Reassortment was also at the center of a wish that a reassorted virus would have a lower case fatality rate.
There was no mention of recombination. WHO is still wishing that the virus can only affect a limited population and will become less virulent, as it becomes more able to transmit human to human, which is not a requirement for a recombinant. The human to human bird flu cases show little evidence of lowered case fatality rates.