Breakthrough in H7N9 study a boost for bird flu drug research

HONG KONG — A team of researchers at the University of Hong Kong has cracked the mystery behind how the deadly H7N9 virus has attained a higher ability to infect humans while also being contagious among avian species, placing the city at the forefront of bird flu drug development.

Scientists analysed the DNA of H7N9 virus strains collected since the 2013 outbreak, and identified a gene mutation that allowed it to adapt to human cells.

The research, headed by Professor Chen Honglin of the university’s State Key Laboratory of Emerging Infectious Diseases, was published in the international scientific journal Nature Communications.

Chen said the findings could “help monitor the emergence and transmission of the bird flu virus in humans and prevent human-to-human infection, as well as provide a new target for antivirus drug development”.

The first confirmed infections of the new H7N9 strain of bird flu were reported on mainland China in March 2013. It began to spread across the country and even overseas.

A latest wave surfaced in mainland China in October and Hong Kong has recorded five imported cases so far.

As of Saturday (March 18), there were a total of 1,329 confirmed human H7N9 cases around the world since the 2013 outbreak, claiming at least 492 lives.

Most of the cases were from mainland China, while Hong Kong registered 21 and 10 other incidents were distributed across Taiwan, Canada, Macau, and Malaysia, according to latest figures in the weekly avian influenza report by the Centre for Health Protection.

The HKU study found that a gene mutation with the H9N2 strain occurred in the 2013 H7N9 virus, combining with genes from other viruses carried by wild birds, to evolve into the current H7N9 strain that can infect humans.

Chen said that it was rare for avian viruses to be transmitted to humans, but the mutation in this case was particularly aggressive and adaptable.

He added there was no evidence however that this could result in higher risks of infection between humans. The unique mutation has also not been detected in other avian viruses.

Signs and symptoms of H7N9 infection in people mainly start with a fever and cough. In some cases, patients can suffer from severe pneumonia, septic shock and multi-organ failure, leading to death.

Chen warned that as long as people were exposed to infected birds or contaminated environments, more illnesses could be expected.

He said: “There is currently no publicly available vaccine to protect against the H7N9 virus infection. One has to keep good personal hygiene habits and stay away from high-risk places like wet markets.” SOUTH CHINA MORNING POST