January 28, 2014
H7N9 Bird Flu Resurges, China Halts Poultry Trade
Lawrence LeBlond for redOrbit.com - Your Universe Online
As China embraces for the Lunar New Year this week, the country’s health officials are also dealing with a resurgence of the dangerous H7N9 bird flu that first started sweeping across the country in February 2013.
The World Health Organization (WHO) has been receiving nearly daily reports on new laboratory-confirmed cases of human infection with H7N9 since the beginning of the year, with close to a hundred cases reported and 19 deaths.
Overall, more than 245 cases have been confirmed along with 56 deaths since the first infections cropped up nearly a year ago, according to the Hong Kong Department of Health.
China got the disease under control in early May 2013 after culling millions of chickens believed to be the source of the deadly flu strain. Within days of the mass cull reports of flu-like symptoms waned and case counts dropped significantly. While only a handful of cases were reported between May and late fall 2013, experts were positive a resurgence would come with the colder temperatures.
How right they were.
In the first week of the New Year – from Jan 1 to Jan 7 – the WHO only reported three new lab-confirmed cases of infection from H7N9 bird flu. However, starting on Jan 8 and continuing through the following week ending Jan 14, the WHO reported 20 additional cases. From Jan 15 through Jan 21, case reports climbed by 36 and in the last week an additional 34 cases were confirmed.
Nearly all of the cases of H7N9 have been reported from mainland China, but some have been found in Taiwan and Hong Kong. As a result of the latest infections and after a chicken sample imported from mainland China tested positive for the H7 virus, Hong Kong has culled 20,000 chickens to try and bring the risk of infection down.
According to BBC’s Juliana Liu, this was Hong Kong’s first mass culling of live poultry in three years – its last cull was in 2011 after an H5N1 outbreak. Last year’s massive poultry cull occurred in mainland China.
According to a WHO report, most of the cases of H7N9 bird flu have come from exposure and contact with live poultry or contaminated environments.
"When the chickens are very overcrowded, at the time of festivals like Christmas, Chinese New Year, and there are no bio-security measures taken, then the virus spreads through poultry very quickly," Dr. Kwok-Yung Yuen, chair of infectious diseases at the University of Hong Kong, said in a statement to CNN's Madison Park. "It's also possible that travelers will bring live poultry back to their own villages."
While the WHO does not currently advise against travel or trade it does warn that “further sporadic human cases are expected” across the region during the Chinese Lunar New Year and beyond.
The Chinese Lunar New Year is one of the biggest annual human migrations on the planet as most people in China travel to spend time with their loved ones during the long holiday season.
Besides culling chickens, Hong Kong has also suspended all fresh poultry imports from mainland China for the next 21 days to slow transmission risk. This order comes just prior to the New Year celebrations, when poultry sales are generally at their highest levels. Poultry markets will reopen on Feb 18 barring any unforeseen issues.
"Agriculture, Fisheries and Conservation Department officers will inspect all the local chicken farms and collect more samples for testing to ensure that local farms are not affected by H7 avian influenza," Secretary for Food and Health Dr Ko Wing-man said in a statement to Reuters.
Most human cases of H7N9 have come from contact with live poultry but in some instances human transmission has occurred, albeit not sustainably.
The H7N9 virus appears to be deadlier than seasonal flu, but has been discovered to be less virulent than the H5N1 bird flu strain. H7N9 has shown roughly a 30 percent mortality rate, dropping closer to 25 percent with the latest onslaught of confirmed cases.
While Hong Kong has shut down its poultry markets for 21 days, Shanghai has reported that it will halt live poultry trade until April 30 to prevent the spread of bird flu, according to a Xinhua report.