Regarding the first person in Vietnam to be infected with avian flu A/H9 in Vietnam, Dr. Nguyen Luong Tam, Deputy Director of the Department of Preventive Medicine under the Ministry of Health said, according to medical documents in the world, the most frequently identified sub-types of avian influenza A viruses that have caused human infections are H5, H7 and H9 viruses.
Among them, H5 is a highly virulent strain that often causes large outbreaks and mass deaths of poultry. However, the H5 sub-type of avian influenza A virus is transmitted into humans, it causes severe symptoms and a very high mortality rate. Meanwhile, the sub-types H7 and H9 are low virulence strains that usually cause mild disease and rarely cause mass deaths in poultry. Combined with these strains are N antigen subtypes from 1 to 9. The combination and recombination of H and N antigens can create many types of avian influenza that infect humans.
Currently, avian influenza viruses including strains H5N1, H5N6, H5N8, H7N9, and H9N2 have been recorded in animals in the world with the main strains including H5N1, H7N9, and H9N2.
For the first case of influenza A (H9) in the country, through epidemiological investigation, the patient's place of residence was in a poultry market. Worse, people trade poultry in front of the patient's house. However, there have been no reports of sick or dead poultry around the area where the patient is living. The failure to detect H9 outbreaks in poultry makes epidemiological surveillance, identification and localization of outbreaks difficult, which may affect the implementation of disease control measures, said Dr. Nguyen Luong Tam.
At the same time, the health watchdog recommended that people and those raising, trading, transporting, and slaughtering poultry should strictly comply with disease prevention measures when in direct contact with poultry or going to high-risk areas such as markets or poultry farms or markets where people sell live poultry and animals.
Meanwhile, Associate Professor Tran Dac Phu, former Director of the Department of Preventive Medicine, said that influenza A (H5N1) has so far mainly infected humans in the country. Thus, after the discovery of the first case of influenza A (H9) in humans, it requires more vigilance because influenza virus strains can easily mutate into more severe or more virulent strains, spread quickly and have more severe symptoms.
According to Director Hoang Minh Duc of the Department of Preventive Medicine, up to now, there is no vaccine or specific treatment for avian influenza in humans, so the death rate is very high, up to 50 percent.
At the same time, scientists around the world have identified many strains of influenza transmitted to humans such as A (H5N6), A (H5N1), A (H5N8), and A (H9). The simultaneous circulation of many strains of the avian influenza virus and the spread to mammals is a worrying factor because it possibly causes an increase in avian influenza epidemics in humans. Therefore, it is necessary to continue to strengthen disease control in poultry flocks to prevent the risk of the disease spread, Dr. Duc warned.
