Roundup, Netherlands scientists through experimental proof that the vaccination in poultry avian influenza vaccine to prevent the spread of the virus, even if the vaccine is not exactly a "counterpart", also can prevent outbreaks.
Ever since the scientific community on vaccination in poultry also disputed the validity. Some scientists believe that vaccinations would promote virus evolution, or even contribute to virus resistance. Therefore, some countries in the prevention and control of H5N1 avian influenza virus, or preferred culling infected all the poultry in the vicinity of the point, the prohibition of trade in live poultry and poultry products.
Netherlands Institute for animal disease control Central, scientist, first using contagious model experiment proved that the vaccine to control the spread of avian influenza virus. Their paper published in 28, published by the United States National Academy of Sciences.
In the experiment, the researchers are using a type of highly pathogenic H7N7 avian influenza virus strains, and vaccines are preventing H7N1 virus type type and H7N3 virus strains. They first give 10 chickens injection virus and vaccination vaccine for healthy chicken and infected chicken mixed together, and at any time to check the status of the chickens.
The results of the experiment found that infected chickens have all outbreaks of the disease symptoms and death, vaccination had two vaccines of chicken are also "alive", but without the virus. In controlled trials, two groups of unvaccinated chickens and infected chickens polyculture, 10 days appear symptoms of infection, mortality rates are as high as 60 percent and 80 percent.
Researchers also found that, in order for the antibodies to poultry stable level, vaccine effectiveness takes time. In the experiment, part of the H7N3 vaccine inoculation of chickens, a week after the vaccination and infected chickens polyculture also appears when you symptoms of avian influenza. But if the chickens vaccinated after two weeks and infected chickens polyculture, you all can stay healthy.
On the results of statistical analysis showed that the H7N7 avian influenza viruses in unvaccinated poultry in transmission index reached 33, can quickly cause disease; vaccine immunization with H7N3 in a week of chickens, infectious index drops to 0.3 H7N1 vaccine inoculation, in a week of chickens infected index 0.03; in respectively two vaccine inoculation of 2 weeks of chickens, infectious index are dropped to 0.
The researchers therefore believes that vaccination can greatly reduce the highly pathogenic avian influenza virus propagation velocity in order to prevent the outbreak occurred. They also pointed out that, in today's world many national prevention and control of H5N1 highly pathogenic avian influenza viruses, this result also has important implications.
Responsible for the study of the text said that Van wave now is becoming increasingly clear that the H5N1 avian influenza virus can cross the species barrier "," humans and may in future raises serious human influenza outbreak. Whereas poultry vaccination can prevent the virus in domestic poultry, but also can reduce the virus in poultry and human transmission probability, a "critical measures". (Finished)
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