The H7N9 strain of avian influenza is more lethal than the coronavirus that caused the global SARS outbreak in 2003, a National Taiwan University Hospital doctor said.
Citing a University of Hong Kong report, Huang Li-min (黃立民), head of the hospital’s Department of Pediatric Infectious Diseases, said the H7N9 virus can develop very quickly and has an estimated case fatality rate of more than 10 percent.
“This rate is higher than that of the SARS virus,” which the WHO estimates is approximately 8 percent, Huang said.
According to the Centers for Disease Control’s Web site, there have been 114 confirmed cases of H7N9 in China with 23 deaths as of 6pm on Friday, which translates into a mortality rate of about 20 percent.
However, the report said there are at least as many uncorfimed as confirmed cases, putting the bird flu strain’s mortality rate slightly above 10 percent. The H7N9 strain was not thought to be infectious to humans until March 31, when China reported its first cases of human infection. Prior to that, the virus had only been observed in birds.
The first case of H7N9 infection in Taiwan was a 53-year-old man who fell ill with symptoms of fever and fatigue on April 12, three days after returning to Taiwan from Suzhou in China’s Jiangsu Province, one of the areas affected by H7N9.
Huang said the patient was transferred to National Taiwan University Hospital on April 20 and has been treated in a negative pressure quarantine ward since then. The patient is receiving extracorporeal membrane oxygenation treatment (ECMO) and his condition is “serious, but stable,” he added.
Chang Shan-chwen (張上淳), the hospital’s deputy superintendent and an expert on infectious diseases, said Taiwan’s first SARS patient was also treated at the facilitiy.
“But while the SARS patient was in serious condition, he did not need ECMO therapy, a sign that the H7N9 virus is even more virulent,” Chang said.
Keiji Fukuda, the WHO’s assistant director-general for health, security and the environment, said at a news conference in Beijing last week that H7N9 is one of the most lethal viruses recorded so far.
The Central Epidemic Command Center on Friday said the observation period for suspected H7N9 carriers or for those who might have been exposed to the virus will be extended from seven to 10 days. The measure is aimed at increasing the effectiveness of H7N9 detection since studies published in medical journals such as the Lancet or the New England Journal of Medicine say the virus’ incubation period could be as long as 10 days instead of seven, as was originally believed, the center said.