Yoshihiro Kawaoka of the University of Wisconsin-Madison and University of Tokyo reports that examination of the genetic sequences of H7N9 isolates from four of the victims show a protein mutation that efficiently replicates in human cells.
The mutation also allows them to thrive at the cooler temperatures of the human upper respiratory tract, particularly the nose and throat.
The findings, which are the result of a collaborative study conducted by a team led by Masato Tashiro of Japan's Influenza Virus Research Center, National Institute of Infectious Diseases, were published in the April 11, 2013 edition of the journal Eurosurveillance.
The new strain of bird flu has so far infected 33 people and killed nine, as reported by the Chinese Center for Disease Control and Prevention.
Kawaoka says what is troubling is the fact that the virus, while avian, is evolving, and due to characteristics similar to mammalian influenza viruses, is developing an ability to infect humans, raising the possibility of a pandemic.
Experiments currently being conducted from the genetic sequences deposited by Chinese researchers into an international database are now focused on the development of a candidate vaccine to prevent infection on a wider scale.
Commonly used antiviral drugs, ion channel inhibitors which trap the virus in the cell, have not been effective.
A more promising candidate is oseltamivir, a new neuraminidase inhibitor which works by preventing the virus from chemically cutting ties with its host cell, thus slowing its spread. — TJD, GMA News
source: gmanetwork.com
