Vietnamese Doctor Blames `Mutating Virus' For High Death Rate
# 1791
The doctors of Vietnam have seen a good deal of bird flu over the past 5 years, and up until recently, have managed to salvage roughly 50% of the patients they've treated.
This year, however, all four victims of the virus have died. And last year, 5 of 8 reported victims succumbed.
This week the idea has been floated several times in the Vietnamese press that something has changed in the virus, a mutation, that is making it more lethal.
The CFR (Case Fatality Ratio -% of infected people who die) in 2005 was reportedly 43%, and in 2006 and 2007 among known cases, the CFR jumped to 68%.
Worldwide, 23 bird flu victims have been reported this year, and 18 of those have died. The fate of several more still hang in the balance.
Even assuming all those who are currently hospitalized survive, the CFR (Case Fatality Rate) among known cases this year would exceed 78%.
Obviously this is a worrisome trend.
Of course, there are a couple of `unknowns' that we need to consider when we talk about the rise of the CFR of bird flu. First, the assumption is that we aren't missing many `mild cases'.
If mild cases were going undetected, where the patient was either asymptomatic, or was briefly ill but recovered, then the CFR of the virus would be far lower than is reported today.
For a long time it was assumed that there were mild cases, and that we were seeing only the `sickest of the sick'. But recent serological surveys in villages where bird flu was present cast doubt on that assumption. Simply put, they were unable to find much evidence of mild or asymptomatic infection among people who were exposed to the virus.
Now, that doesn't mean it doesn't happen. But it does indicate that if mild cases do exist, they are probably rare.
And second, we need to ask, are there other contributing factors that might account for the rise in the CFR other than a mutation?
Here we would need some epidemiological work done, to determine (among other things) if patients this year are waiting longer to seek medical aid, or if more of them had a pre-existing illness than in previous years.
Simply put, there could be other reasons, besides a mutation in the virus, that could account for a rise in the mortality rate. If Vietnamese scientists have isolated a specific genetic change in the virus they feel is responsible for this uptick in the CFR, they haven't reported it.
In any event, here is how the Vietnamese press is reporting this story.
H5N1 mutates, 90% of patients die
16:38' 14/03/2008 (GMT+7)
VietNamNet Bridge – The Veterinary Agency on March 13 confirmed that the southern province of Soc Trang is the newest place bird flu has been found. Meanwhile, H5N1 virus seems to be more toxic.
According to Saigon Giai Phong newspaper, around 900 of 1,300 ducks owned by a family in Vinh Binh hamlet, Vinh Bien commune, Nga Nam district, Soc Trang province died of bird flu, raising the total number of provinces and localities with bird flu to nine. They are Quang Ninh, Ninh Binh, Vinh Long, Phu Tho, Ha Nam, Tuyen Quang, Hanoi, Quang Tri and Soc Trang.
Nguoi Lao Dong newspaper on March 13 quoted Doctor Nguyen Hong Ha, Vice Head of the National Hospital for Infectious and Tropical Diseases, as saying that H5N1 is mutating because the fatality rate of type A/H5N1 patients is over 90% recently.
Dr. Nguyen Huy Nga, Head of the Veterinary Agency, said the World Health Organisation (WHO) has continuously warned about the mutation of H5N1 virus and the risk of transmission of the virus from humans to humans.
So far this year 18 type A/H5N1 patients have been reported, including 15 deaths, mainly in China, Indonesia and Vietnam (4 cases).
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