A controversial study on the ‘bird flu’, the avian H5N1 influenza virus, has finally been released.
The research was done to test how easily the virus could become transmissible to mammals. The study is controversial because it essentially shows the steps necessary to weaponize the virus. So much so that the National Science Advisory Board for Biosecurity (NSABB) recommended removing critical information from the study, and another similar study, before publication. For the NSABB, it was an unprecedented request, wanting the methodologies, and the mutations needed for the transmission to mammals, removed from the studies.
Proponents of the study have argued that the research is essential to prepare for what could become a global pandemic.
“Our study shows that relatively few amino acid mutations are sufficient for a virus with an avian H5 hemagglutinin to acquire the ability to transmit in mammals,” says Yoshihiro Kawaoka, a University of Wisconsin-Madison flu researcher whose study of H5N1 virus transmissibility was at the center of the debate.
“This study has significant public health benefits and contributes to our understanding of this important pathogen. By identifying mutations that facilitate transmission among mammals, those whose job it is to monitor viruses circulating in nature can look for these mutations so measures can be taken to effectively protect human health.”
He also cautions that there may be unknown mutations that allow the same transmissibility to humans. It’s critical to continue the research and develop a better understanding of how it works he says.
The study was done by an international team of researchers, led by Kawaoka, a professor of pathobiological sciences and a leading flu expert. It’s conclusion is that some of the virus’s circulating in the natural environment would only need four mutations to become more virulent to humans. A subset of the necessary mutations has in fact already been detected in some poultry in Egypt and southeast Asia.
The research suggests that with how quickly virus’s mutate and exchange genes with each other, the likelihood of them acquiring the right mutations and becoming a pandemic are much greater than many experts had believed.
“H5N1 viruses remain a significant threat for humans as a potential pandemic flu strain. We have found that relatively few mutations enable this virus to transmit in mammals. These same mutations have the potential to occur in nature,” explains Kawaoka.
H5N1 has already in its much less virulent form infected over 600 humans, killing more than half of them. But as the research suggests, with just a few mutations it could spread exponentially throughout the human population and become a pandemic.
Whether or not the virus will acquire these mutations in the wild is considered an open question though. “It is hard to predict. The additional mutations may emerge as the virus continues to circulate.”
“Should surveillance activities identify flu strains accumulating additional key mutations, these emerging viruses should then be priority candidates for vaccine development and antiviral evaluation,” says Kawaoka.
Source: UW- Madison
Image Credits: PHIL/CDC