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September 20, 2011
This threat is not just for the birds
N. Gopal Raj
Excerpt:
With outbreaks in poultry, the virus has from time to time jumped to humans too. Since 2003, it has infected 565 people, according to data maintained by the WHO. More worrying is the fact that the resulting disease killed half of them.
However, an analysis published in Eurosurveillance recently by scientists at Germany's Robert Koch Institute found that the human case-fatality rate from H5N1 infection varied from 28 per cent in Egypt to 87 per cent in Indonesia. Even when adjusted for age, sex and time to hospitalisation, Egypt still had the lowest odds of people dying from the virus. Differences in the viral strains found in Egypt and Asia could not be ruled out as a factor, they said.
The scientists also noted that longer delay, from the onset of symptoms to hospitalisation and belonging to older age groups were associated with higher mortality.
Human sickness and death from H5N1 pale into insignificance when compared to many other infectious diseases that plague the world (malaria, for instance, is responsible for nearly a million deaths a year). But the worry has long been that this bird flu virus might take on a pandemic form and then sweep swiftly across the globe.
At present, the virus is not able to easily infect humans or pass from one individual to another. Could the virus become better adapted to humans through mutation and exchanging genes with other flu viruses (a process known as reassortment)? If that does happen, would the H5N1's lethality be reduced in the process?
The rationale for particular concern about a H5N1 pandemic was not its inevitability but its possible severe impact on human health, wrote J.S. Malik Peiris, a well-known virologist at the University of Hong Kong, and others in a paper published in 2007.
Such a pandemic, especially if it arose by the bird flu virus directly adapting to humans, rather than through genetic reassortment with a pre-existing human virus, could well be unusually virulent in humans. “Thus, an H5N1 pandemic is an event of low probability but one of high human health impact,” they concluded.
Full text:
This threat is not just for the birds
N. Gopal Raj
Excerpt:
With outbreaks in poultry, the virus has from time to time jumped to humans too. Since 2003, it has infected 565 people, according to data maintained by the WHO. More worrying is the fact that the resulting disease killed half of them.
However, an analysis published in Eurosurveillance recently by scientists at Germany's Robert Koch Institute found that the human case-fatality rate from H5N1 infection varied from 28 per cent in Egypt to 87 per cent in Indonesia. Even when adjusted for age, sex and time to hospitalisation, Egypt still had the lowest odds of people dying from the virus. Differences in the viral strains found in Egypt and Asia could not be ruled out as a factor, they said.
The scientists also noted that longer delay, from the onset of symptoms to hospitalisation and belonging to older age groups were associated with higher mortality.
Human sickness and death from H5N1 pale into insignificance when compared to many other infectious diseases that plague the world (malaria, for instance, is responsible for nearly a million deaths a year). But the worry has long been that this bird flu virus might take on a pandemic form and then sweep swiftly across the globe.
At present, the virus is not able to easily infect humans or pass from one individual to another. Could the virus become better adapted to humans through mutation and exchanging genes with other flu viruses (a process known as reassortment)? If that does happen, would the H5N1's lethality be reduced in the process?
The rationale for particular concern about a H5N1 pandemic was not its inevitability but its possible severe impact on human health, wrote J.S. Malik Peiris, a well-known virologist at the University of Hong Kong, and others in a paper published in 2007.
Such a pandemic, especially if it arose by the bird flu virus directly adapting to humans, rather than through genetic reassortment with a pre-existing human virus, could well be unusually virulent in humans. “Thus, an H5N1 pandemic is an event of low probability but one of high human health impact,” they concluded.
Full text:
