Diary Prequel Package — page 273

In the tracheal insertion studies, 106 virus is inserted directly into the trachea. Again, this is a dose and a situation that would be extremely difficult, if not impossible, to achieve by aerosolized transmission. In these experiments, when this amount of wild type (unmodified) HPH5N1 is inserted into the trachea, all animals die on day 3. Similarly, when the modified H5N1 is inserted, all animals die on day 3. However, and importantly, when 2009H1N1 that was shown to be a mild pathogenicity virus was inserted under the same conditions, it killed some, but not all the animals. Although, this was a qualitative and not a quantitative study, it strongly suggests that in this model, the modified H5N1 is not dramatically different from the 2009 H1N1 in pathogenicity. Also, it should be pointed out that in the ferret model, 2009 H1N1 is much more transmissible (100% transmission on day one) than is the modified H5N1. Specifically, transmission with the modified H5N1 does not occur until day 3 to 4 and even then it is only 75% transmissible. This suggests that the R0 may be less than 1. This is important with regard to concerns over the potential catastrophic effects of lab accident and the known conditions that are needed for the start of an epidemic/pandemic. In this regard, there should be serious discussion of how pandemics occur. Nancy Cox can elaborate. Ferrets are naïve to influenza virus, i.e. they have no pre-existing immunity. Humans do have pre-existing immunity to influenza viruses due to repeated exposures (except in young children) and/or vaccinations. It is EXTREMELY IMPORTANT to point out that if you vaccinate the ferrets with seasonal H1N1, they are not protected against death from tracheal insertion of high dose (106 infectious doses) modified or wild type H5N1. Fouchier did not test the effect on transmission yet (moratorium). However, if you pre-infect ferrets with seasonal H1N1, let them recover and then insert high dose H5N1 into their trachea, this fully protects against disease and no ferrets die. This strongly suggests that pre-existing immunity due to prior infection with seasonal influenza A protects against serious disease with this modified virus (heterosubtypic immunity). This could be a possible explanation for why so few people get infected with H5N1 in the wild. Yoshi Kawaoka Experiments (Nature). The studies of this investigator are very similar to those of Fouchier except that Kawaoka took the HA from the HPH5N1 and did random mutations from which he selected those that enhanced transmissibility when this HA was reassorted with the 2009 H1N1to make a hybrid of the H5N1 and the 2009 H1N1. This is something that we are concerned could happen in the wild. He then did similar passages as described above. Kawaoka's results differed from the Fouchier study in that although his virus was transmissible, it was not any more pathogenic than the 2009 H1N1 influenza. EPIDEMIOLOGICAL DATA: With regard to the importance of these data for the real and present danger of the evolution of H5N1 in the wild, as well as for the impact on surveillance, Kawaoka and Fouchier have done some epidemiological "mapping" of their modified virus with what is going on in the wild. Viruses were studied that were obtained from chickens in Japan, Mongolia, Nepal, and Egypt as well as viruses from people infected with H5N1 in Egypt. Some of the mutations that Fouchier and Kawaoka described involving the PB2 gene (627 K) and the receptor binding genes (HA) were present in 100% of the H5N1 viruses that infected humans