Background: Bird flu or avian flu, caused by H5N1 virus, is a new emerging infectious disease. It is noted
that this H5N1 virus jumped the species barrier and caused severe disease with high mortality in humans in Vietnam
and Thailand. Many were reported noted on nucleotide for HA of H5N1 in Thailand. However, there is no
comparison on the structure of the protein encoded by the isolated HA in Thailand.
Method: Here, the author performed this study to compare the secondary and tertiary structures of the isolated HA
from different sources in Thailand. The author used a bioinformatic technique to predict the secondary and tertiary
structures of HA of H5N1 isolated in Thailand.
Result: Using NNPREDICT and CPHmodels 2.0 servers, the calculation for secondary and tertiary structures of
H5N1 of HA isolated in Thailand was performed. The predicted structures of all 20 HA are same.
Conclusion: The structures of H5N1 derived from natural and non-natural hosts of virus are same. This implies that
the mutation might not be the important factor leading to the cross species infection in Thailand but the individual
defect of non-avian host might be the possible factor.
Keywords: bird flu, Thailand, HA, structure, mutation.
