Infection with the H3N8 avian virus causes acute respiratory distress syndrome in humans and can even be fatal. The virus is widespread in chicken farms and until now the characteristics of how it can be transmitted from animals to humans have remained little known.
A new study conducted by researchers in China and the UK has revealed that a subtype of the bird flu virus, endemic in poultry farms in China, is undergoing mutations, which could increase the risk of transmission of the disease to humans.
The researchers also say the findings raise concerns about a potential emerging epidemic or pandemic, and that concerted research is needed to closely monitor such viruses in poultry and humans.
The results, which were published Monday in the medical journal Cell, show the study of a human isolate — from a human patient — of the H3N8 avian influenza virus (AIV).
Using laboratory mice and ferrets as models for human infection, the study found that the virus underwent several adaptive changes to cause severe infections in animals and to make it airborne between animals.
“We demonstrate that an H3N8 avian virus isolated from a patient with severe pneumonia replicated efficiently in human bronchial and lung epithelial cells, was highly deleterious in its effects in laboratory mammalian hosts, and could be transmitted by respiratory droplets “said Professor Kin-Chow Chang, from the University of Nottingham, UK, according to News.ro.
He explained that the virus acquired the binding preference for human receptors and the amino acid substitution PB2-E627K, which are necessary for airborne transmission.
Human populations, even when vaccinated against human H3N2 virus, appear to be immunologically naïve to the emerging mammalian-adapted H3N8 AIV and may be vulnerable to infections of epidemic or pandemic proportions.
Acid resistance is also an important barrier that avian influenza virus must overcome to acquire adaptability and transmissibility to new mammals or humans.
“The current new H3N8 virus has not yet acquired resistance to acids. Therefore, we should pay special attention to the change in acid resistance of the new H3N8 virus″said Professor Jinhua Liu of Beijing Agricultural University, China.
The study, entitled “Airborne transmission of H3N8 avian influenza virus isolated to humans between ferrets”, was carried out in collaboration between the universities of Nottingham, Beijing Agricultural University (China), the Chinese Academy of Sciences and the Chinese Center for Disease Control and Prevention .
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2023-09-05 13:39:41
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