China H7N9 outbreak
January 28, 2014
It's the first time since 2011 that Hong Kong has imposed an import ban on live chickens and carried out a cull. After detecting a chicken infected with the H7N9 strain of avian influenza at the Cheung Sha Wan wholesale market, government authorities closed the market, banned the sale of live chickens, and began the cull of 20,000 birds.
"This has been our control strategy for the last 16 years," says Dr. Kelvin To at the University of Hong Kong's Department of Microbiology. "It's a necessary measure to stop the spread of this virus."
But this is the Lunar New Year festive season - a time when it's traditional to buy live chickens for consumption - and wholesalers fear they will lose millions in local revenue.
They say the authorities should have stopped the infected chickens at the border with mainland China. The infected samples were detected in a batch of chickens from Guangdong Province - the same area, incidentally, where SARS (severe acute respiratory syndrome) was first discovered.
"For every batch, we screen a proportion of the chickens and test them for H7N9, and if one tests positive, just as in this case, then the government takes action. We also screen chickens in Hong Kong because we have chicken farms here too," says Dr. To.
The chicken that was just detected with the virus, however, was in a batch that came from China, the doctor added. "So we think there's a definite risk in the chickens coming from China."
More cases than last year
Figures published by Hong Kong's Department of Health on Tuesday (28.01.2014) show "a total of 246 human cases of avian influenza A(H7N9) confirmed in the Mainland."
Six new cases were reported on Monday, including one death in Guangdong. Others were hospitalized in Jiangsu, Hunan and Fujian.
The health department says control measures are in place, such as thermal imaging systems for checking the body temperatures of inbound travelers.
"The situation now is much worse than last year, because in the first outbreak there were about 130 cases, but just in the past month there have already been another hundred cases," Dr.To said.
In Geneva, the World Health Organization takes a slightly different view. The WHO's spokesperson for avian influenza, Gregory Hartl, cites the fact that we are still not seeing human-to-human transmission of the virus.
"Frankly, nothing has changed from our perspective. This is the same pattern of infections that we have seen since the beginning and that means that the infections come from birds and infect humans, but humans do not transmit the virus from one person to another," says Hartl. "So this is still what we would call sporadic cases of infection from birds to humans. It's the same pattern we've seen since March 2013."
It is also winter, providing any flu virus with the perfect conditions to thrive and spread.
"January is the height of the flu season. Flu viruses circulate much more widely and live longer in colder weather…. It is not surprising," says Hartl.
Hong Kong experts like Dr. To say the same thing.
But the heightened concerns in China are difficult to overlook, especially as people prepare for the Chinese New Year, during which many millions travel very far to celebrate with their families.
"It's not the traveling itself that's a problem," says Dr. To at Hong Kong University, "because the virus is not transmitted from human-to-human. So the traveling is not an issue unless people are traveling with live chickens, which I don't think is happening."
What is significant during this period of increased travel, however, is that people are becoming infected in one place and then travelling on to a place where the virus has yet to have occurred. In a sense, they are causing statistical blips.
"In Hong Kong, we have three imported cases. All patients did not acquire the virus in Hong Kong, but from China, and that's because of their frequent travel between Hong Kong and China. So you may find new cases in areas that have not reported H7N9 before, but that doesn't mean that the patient acquired the infection in that location," Dr. To said.
Learning from history
Hong Kong has tried to learn from its past experiences. In 1997, it was struck with the first H5N1 avian influenza outbreak. Then, in 2003, it was the focus of the SARS (severe acute respiratory syndrome) epidemic in which hundreds died.
Dr. To says history has made people in Hong Kong more proactive on bird flu. Perhaps the mainland can take a leaf out of its book.
"I think so, yes. Not just because of SARS, but also because of 1997.... People in Hong Kong are aware of the risks and they're prepared to take action against this virus," he says. "From my own experience, I think Hong Kong people are more alert on this issue than what people are feeling in China."
The South China Morning Post reports that Hong Kong's secretary for food and health, Dr. Ko Wing-man, says the government has contacted mainland authorities, requesting they help trace the current outbreak.