H7N9 evolving, could eventually spread between humans: expert
Staff Reporter 2013-04-16 08:49
An H7N9 victim in central China's Henan province. (Photo/CNS)
The deadly new strain of avian influenza that has so far killed 14 people and infected a total of 63 across China could eventually become capable of human-to-human transmission, according to a leading infectious disease control expert.
In an interview on state broadcaster CCTV on April 14, Zhong Nanshan, head of the Chinese Medical Association and director of the Guangzhou Institute of Respiratory Diseases, said health authorities remain concerned that the H7N9 virus could evolve to pass from person to person, allowing what has so far been a limited outbreak to become a major pandemic.
Just because there are currently no confirmed cases of human-to-human transmission does not mean that human-to-human transmission is not possible, Zhong said. The SARS virus, which killed more than 600 people in 2003, was not initially a high pathogenic virus but became one later through genetic mutation, he said. Factually, there are no cases of human-to-human transmission, but this does not prove that the virus cannot spread between humans, he added, noting that researchers have already established that the virus is changing.
Zhong said there is still much that is not known about the virus, which has thus far killed a quarter of the patients to have contracted it. We cannot say the virus has a high mortality rate at this stage; all we can say is that the morality rate is high among those who have fallen seriously ill from the virus, he said.
As for why some victims become more ill than others from the virus, Zhang said there is no real answer right now, although everyone's immune system reacts differently to a virus attack. The general incubation period for the virus is around seven days, he said.
The expert also shot down the popular theory that the thousands of dead pigs pulled out of a Shanghai river last month was linked to the H7N9 outbreak. He said the theories are merely speculation as there is no evidence to support that the pigs were killed by H7N9. Tests have also found that the eight genetic fragments of the virus all come from birds, not pigs, he said.
On the topic of treatment, Zhong said there is presently no drug that has proven particularly effective against H7N9. The key is to identify the symptoms and provide treatment as soon as possible; even one hour could be vital, he added.
Zhong warned against rushing out to buy the herbal medicine Indigowoad Root ("banlangen" in Chinese), which was heavily used during the SARS epidemic 10 years ago and has again proven popular among locals looking for a preventative measure. Research has shown that the root contains some active ingredients that could be effective against the H3 and H7 bird flu subtypes, but the amount of the ingredient is very low, Zhong said, while on the other hand large doses can be toxic and damage the stomach.
The best way to keep the virus at bay is to be alert and avoid situations or conditions that may put you at risk, he said.
