Speaking at a meeting of the Royal Society in London on Tuesday (April 3), one of the scientists whose research resulted in an H5N1 virus that could spread easily between ferrets has revealed the details of how he did it. University of Wisconsin, Madison, virologist Yoshihiro Kawaoka told about 150 attendees of the 2-day meeting that 4 mutations and genes from the H1N1 virus appeared to make the bird flu virus strain readily transmissible between ferrets in his lab.
Kawaoka's revelations, which came on the heels of last Friday's National Science Advisory Board for Biosecurity recommendation that his paper be published in full, detailed his methodology. First, he introduced two mutations—N224K and Q226L—into the haemagglutinin (HA) protein of H5N1 that made the virus capable of sticking to receptors on human tracheal cells. Then he created a chimeric virus by combining the mutated HA protein with genes from the H1N1 virus, which sparked a pandemic in 2009. Kawaoka identified another HA mutation, called N158D, that allowed the virus to spread between ferrets that were not in direct physical contact. A fourth mutation, T318I, also showed up in the H5N1 strain, but its role in making the virus more transmissible among mammals is less clear.
Though Kawaoka broke his silence, Ron Fouchier of Erasmus Medical Center in Rotterdam, the Netherlands, the lead author of the parallel study that resulted in a highly transmissible H5N1 strain, was unable to do so. The Dutch government is preventing Fouchier from publishing his results until they determine if doing so violates export rules. "I wish Ron could report everything," Kawaoka told ScienceInsider. "We found striking similarities."
Neither Kawaoka's nor Fouchier's versions of the virus were lethal to the animals in their experiments, and they were both vulnerable to current drug treatments.
According to Nature, the journal to which Kawaoka’s group submitted their results, the paper will be published in full "as soon as possible."