International officials collaborating with China CDC to address the outbreak are generally complimentary of the government's responsiveness and transparency in reporting data for cases of human illness. On April 14, Chinese Vice Premier Liu Yandong visited hospitals and public health centres in Shanghai, an indication that the country's top leadership are paying careful attention to the outbreak.
China also benefits from investments in public health infrastructure made over the past decade. Some 550 sentinel hospitals around the country are identifying outpatients at risk of harbouring H7N9, and more than 400 network laboratories are analysing samples. In 2010, the China National Influenza Center became a WHO collaborating centre, one of just five laboratories globally with that accreditation.
One official who declined to be named speculated that even as recently as 5 years ago this outbreak might have gone unnoticed in China; the small group of unusually severe H7N9 cases indistinguishable from the tens of thousands of deaths caused by regular seasonal influenza in China each year.
But as efforts are made to describe the animal reservoir, and virologists assemble a better understanding of the virus itself, epidemiologists must hold out hope that H7N9 will not evolve to better transmit between human hosts, an inherently unpredictable process.
“Genetics is one thing but actual phenotypic behaviour is another”, says Marc-Alain Widdowson, who leads the International Epidemiology and Research Team of the US CDC's Influenza Division. “If it starts to pick up genes which we know are associated with transmissibility or it starts to pick up resistance to some of the antivirals we use, that would be very concerning.”