New Bird Flu No Immediate Threat: U.S. Experts
There's been no clear evidence of human-to-human transmission in Chinese outbreak
On Monday, the World Health Organization announced that it was in talks with the Chinese government about sending experts to help investigate the outbreak.
The good news is that most of the human cases "have been associated with poultry exposure, which is typical with most bird flu outbreaks," Midturi said.
However, the flu strain has also been found in live pigeons being sold as poultry at a market in Shanghai. That has unnerved some experts since any infection among wild pigeons would be tougher to control than among penned-in poultry.
The fatality rate from H7N9 also remains unclear. Although the death rate in China seems high, with six deaths out of 16 confirmed cases, authorities don't know at this point how many people have actually been infected. If hundreds or thousands of people contracted the virus with few or no symptoms, the true fatality rate would be much lower, said Midturi, who is also director of infectious disease at Scott & White Memorial Hospital in Temple.
The current outbreak is reminiscent of the outbreak of H5N1 avian flu in 2003, another bird flu that has killed about 370 people since then, according to the World Health Organization. That outbreak raised fears about a pandemic that never materialized.
There are also differences between the two viruses. Unlike H5N1, H7N9 doesn't seem to cause illness in birds, making it harder to detect and track. But, it's not unusual for flu viruses to not cause symptoms in their bird reservoirs, said Dr. Len Horovitz, a pulmonary specialist with Lenox Hill Hospital in New York City.
But he also added a bit of good news: H7N9 is treatable with currently available antiviral medications.
According to The New York Times, the U.S. Centers for Disease Control and Prevention has started work on what's known as a "seed vaccine" for the virus as a precaution. That vaccine will take at least a month to prepare.
And the Associated Press reported Monday that Chinese health authorities are also at work on a vaccine against H7N9.
"If there was human-to-human transmission, that would be worrisome," said Horovitz. "[But] even then, we don't know how aggressive or fatal it would be."