April 5, 2013
Avian Bird Flu Strain Kills Six In China, CDC Closely Monitoring Situation
Lawrence LeBlond for redOrbit.com - Your Universe Online
Chinese authorities have killed more than 20,000 birds after an unusual strain of the bird flu has surfaced, so far killing six people in the Asian country. The strain was found in pigeons sold at various markets throughout Shanghai, according to state-run Xinhua news agency on Friday.
The city is temporarily closing all live poultry markets while authorities try to determine where the source of the disease derived. It is not clear how long the market closures will last, but officials with the Shanghai Municipal Government noted in a microblog that markets will remain closed until further notice.
The H7N9 avian flu was found in pigeons sold at the Huhai agricultural market, according to Xinhua. The virus had not been previously found in humans until a series of cases cropped up this past week in China. The cull of birds at the Shanghai poultry trading zone also came as US researchers said they were working on a vaccine for the virus.
The Chinese Minister of Agriculture said on Thursday that an analysis showed there existed a strong genetic overlap between the strain found in the Huhai market pigeons and the one detected in humans.
The US Centers for Disease Control and Prevention (CDC) said it was monitoring the new strain. So far the H7N9 strain has only been found in China and does not appear to be capable of being transmitted between humans. Still, the CDC said it is talking with global health officials to determine when and if it may be necessary to start mass-producing a vaccine.
The Chinese infections mark the first time humans have been afflicted by this particular strain of bird flu.
The World Health Organization (WHO) reported on Friday that there was no sign of “sustained human-to-human transmission” of the bird flu in China, but said it was important to keep a close eye on the some 400 people who were in close contact with the 14 confirmed cases so far.
"We have 14 cases in a large geographical area, we have no sign of any epidemiological linkage between the confirmed cases and we have no sign of sustained human-to-human transmission," WHO spokesman Gregory Hartl said during a news briefing in Geneva.
He added that health experts are following up with the contacts to see if any have signs of a virus, and if they have been in contact with anyone else. It is “important to follow up with all contacts in order to know whether or not they do have the virus and/or from whom they contracted it,” he said.
"It is really a severe illness but cases are being well handled and put into intensive care units. There doesn't seem to be any indication of infections in hospital so far [sic]," Hartl told reporters, as cited by NBC News.
The latest death from the bird flu came Thursday night in Huzhou, Zhejiang province. The provincial health bureau said on Friday that a 64-year-old man had passed away as a result of infection from the H7N9 virus. The bureau said he died just hours after doctors confirmed the case.
He was one of the 14 human cases identified so far — all of them in the coastal area of eastern China. The first cases of the virus were reported last Sunday. Four deaths have occurred in Shanghai, two others in Zhejiang.
The ages of those infected have ranged from a 4-year-old child, who was last known to be recovering, to an 83-year-old man. One person in Shanghai who developed flu symptoms after coming into close contact with a patient who died of the virus tested negative for H7N9.
Dr. Joseph Bresee, lead epidemiologist at the CDC´s influenza division, said it is not yet known where the humans who have been afflicted had picked up the virus, but the agency is working with Chinese officials to find the source of human infection.
"There are lots of things happening at CDC to prepare for this virus," Bresee told CNN. "State health departments are readying themselves just in case," and researchers are working on developing a vaccine for this strain, he said.
CDC spokesman Tom Skinner said the agency is continuing to monitor the situation very closely on both a domestic and international front.
The agency has begun reviewing genetic sequence information on the strain to develop a “seed” virus, a genetically modified version of the virus that could be easily used to make a vaccine. Because the CDC is using artificial (synthetic) DNA for this process, Skinner said the seed virus may be available within a few weeks.
He noted that several weeks of testing would be needed to determine if it can be used to make a vaccine. If they can produce a vaccine, production would likely be ramped up over several months. From this point, Skinner said a vaccine against the new strain would not be available for at least five to six months.
Before full-scale production can begin, there are several questions that must be addressed, including whether the virus is being transmitted between humans.
"Right now there is no evidence to suggest that is the case," Skinner said in a telephone interview with Reuters.
Japan´s National Institute of Infectious Diseases (NIID) is to receive samples of the virus this month, repored CNN´s affiliate NHK. The institute is already analyzing genetic information from the virus in order to develop vaccines if needed, said NHK.