China is likely to be using sub-standard poultry vaccine, which would explain recent outbreaks of the deadly H5N1 bird flu virus in poultry, experts feel .
The fear among experts is that the virus could mutate from a disease that largely affects birds to one that can pass easily between people, leading to a human pandemic.
AdvertisementSince late 2003, there have been 141 confirmed human cases of the deadly H5N1 strain of bird flu, all of them in Asia, including six in China. Two people have died from bird flu in China, out of 73 known fatalities in Asia.
According to experts, the problem of substandard vaccines was not exclusive to China.
"If you use a good vaccine you can prevent the transmission within poultry and to humans. But if they have been using vaccines now (in China) for several years, how can one account of so much bird flu?" they ask.
Thirty-one counties in China have reported outbreaks of the H5N1 in poultry this year; only one county remains under isolation with no new outbreaks for three weeks, according to Chinese state media.
"The bad vaccine may stop the disease symptoms in the bird, but the bird carries the virus, maintaining it and changing it. This is most likely what is going on in China. Either there is not enough vaccine, or substandard vaccine is being used. Most probably both," experts say.
While appreciating China's ambitious plan to vaccinate all its chickens, they underline the need for agricultural vaccines to be standardized, as there are sub-standard vaccines of bird-flu all over the world.
Experts warn against underestimating the virus, which has exhibited some of the characteristics of the Spanish flu virus of 1918-1919, which killed an estimated 50 million people.
There are about 10 critical amino acids in the 1918 virus that seemed to be necessary for it to be pathogenic. Many of those changes have been seen in the H5N1, but not all together. Individually, these have been there. The chances of getting all these 10 amino acids together in one H5N1 virus, lined up in the right order, are very minute, but it could happen. With Flu viruses changing every time they multiply, they make mistakes, and these mutations occur naturally, they say.
Experts feel it is not surprising that some strains of the H5N1 have been found to be resistant to Tamiflu, Roche AG's drug that is believed to be capable of reducing the symptoms and chances of complications caused by the virus. Finding the cure in the right doses, duration of treatments would involve combining Tamiflu with a few other anti-viral drugs, such as amantadine and rimantadine.
H5N1 cases in China recently were also found to respond to old-fashioned drugs amantadine and rimantadine. So we need to be thinking more about combinations of these drugs, combinations of amantadine, rimantadine and Tamiflu, they say.
Meanwhile, a CNN-Time survey of Asia-Pacific countries has found that Avian flu is expected to be the biggest global issue in 2006, followed by economic slowdown and terrorism.
The survey, carried out this month in the Asia-Pacific region—Australia, Indonesia, Japan, South Korea and the Hong Kong special administrative region—asked people to identify their biggest concerns from a list including bird flu, terrorism, the war in Iraq, Middle East situation, economic slowdown and higher interest rates, global warming and climate change, pollution and AIDS.