H5N1 virus has had high toxicity mutations

The Pasteur Institute in Ho Chi Minh City has completed and reported to the Ministry of Science and Technology on the project of "Research on decoding of A H5N1 influenza virus genome in Vietnam on human and poultry diseases".

According to the study (from March 2004 to March 2005) of the molecular biology department, Pasteur Institute in Ho Chi Minh City, 24 samples of the virus were decoded. In it, there are 16 virus samples on poultry, waterfowl and five virus samples on human being completely decoded. Virus samples were taken from infected human and poultry specimens in the southern region during the epidemic period from December 2003 to March 2005. The decoding showed that all pandemic viruses were still the most common Z-type H5N1 virus of the region since 2004.

However, the study of the detection of the H5N1 strain of human, poultry and waterfowl in early 2005 had serious mutations, focusing on the key functional areas of the avian influenza virus gene, especially on those surface antigens (HA, NA) and sites that determine hosts as well as areas of virulence regulation (in genes HA, PB2, NS).

There was a mutation in PB2 gene that allowed the virus to reproduce effectively in mammalian cells and highly toxic. At the same time, the occurrence of viral strains in fatal patients with many mutations occurred in all genes.

These are signs that the virus has been integrating mutations to adapt to new hosts and increase toxicity, the community may face the spread of H5N1 from human to human. It is noteworthy that all Vietnamese strains in the study have mutations resistant to Amantadine and Rimantadine antiviral drugs. Therefore, it is necessary and urgent to monitor the virus resistant to oseltamivir (Tamiflu) as well as to store new effective antiviral drugs .

According to this study, simultaneous decoding of the entire genome of the isolated virus from patients and poultry will provide more complete information about the A H5N1 strain of influenza circulating in Vietnam.

However, Dr. Cao Bao Van - head of molecular biology of Pasteur Institute in Ho Chi Minh City, and the chairman of this research project - said that mutations that allow viruses to spread from person to person have not been confirmed. Because there are still some questions to answer: the virus can accumulate mutations to create a human-adapted variant, or a genetic recombination with a human influenza virus that needs to be Prerequisites for forming a pandemic virus strain?

Adaptation of avian influenza virus to people who need intermediate hosts? Do genetic changes coincide with increased toxicity?

LE THANH HA