13 November 2005Yahoo News
Scientists in Vietnam, where bird flu has killed 42 people, said the deadly H5N1 influenza virus had mutated into a more dangerous form that could breed more effectively in mammals, state media reported on Sunday.
The online newspaper Vnexpress quoted Cao Bao Van, director of the Molecule Biology Department of the Pasteur Institute, Vietnam's center of bird flu research, as saying the decoding of 24 samples of the virus taken from poultry and humans showed significant antigen variation.
An antigen is any foreign substance that stimulates the body's immune system to produce antibodies.
Van said the study had showed an antigenic shift involving major antigenic changes of the influenza surface proteins, the HA and NA molecules. These changes can result in the appearance of pandemic viruses.
Van said the study had also found a mutation of the PB2 gene in a virus sample from a patient in Dong Thap, southern Vietnam, who died earlier this year. The mutation allows more effective breeding of the virus in mammals.
The function of the PB2 gene is not completely understood, but scientists believe it codes for an enzyme that helps force the host cell's molecular machinery to make more viruses.
While the study came to no conclusion on the virus's ability to move easily between people, it said the virus had developed resistance to anti-flu agents Amatadine and Rimantadine.
Vietnam, where the H5N1 virus has hit nine of the country's 64 provinces since returning in early October, has recorded 92 cases of human bird flu infection and 42 deaths.
