Experts wait for the big bird flu jump
Pallavi Aiyar
Bejing, May 23 Bird flu has once again raised its deadly head in mainland China. The Chinese Ministry of Agriculture has confirmed that the deaths of 178 migratory birds in the country’s Northwest Qinghai province, have been caused by the avian influenza known as H5N1.
For health experts, this is further confirmation that the virus is now endemic in Asia and many say that it’s not a question of if, but when, the H5N1 mutates into a form that would enable it to spread between humans.
Despite fervent measures to contain the virus since it first appeared in late 2003, including the slaughtering of tens of millions of birds and vaccinating many more, bird flu has continued to spread in Asia. The prospects of eliminating the virus within the next few years now appear to be virtually nil.
‘‘Elimination is a strategy we are no longer looking at,’’ say Maria Cheng, spokesperson for the World Health Organisation (WHO) in Beijing. ‘‘The flu is now established in the region so that eliminating it is not a good possibility.’’ Health experts are trying instead to focus on containment, including the monitoring and vaccination of animals.
Bird flu has affected 11 countries in the region from Japan to Indonesia and WHO says the outbreak is without precedent.
Avian influenza already fulfills 2 out of the 3 conditions for causing a human flu pandemic: the emergence of a new virus to which humans have little or no immunity and the ability of this virus to replicate in humans. The third condition, that the virus must be transmittable from one human to another, is the one standing between the current situation, where the flu is by and large limited to poultry and a possible world wide human flu pandemic of staggering proportions.
Currently, H5N1 is only known to spread between birds and, more rarely, from birds to humans. But as the virus continues to spread there is a distinct possibility that it will mutate in time, enabling human to human transmission.
Says Cheung, ‘‘We have a situation at the moment where both the human influenza virus and avian flu virus are circulating in a region simultaneously.’’
If H5N1 infects a human who is also carrying a human flu virus, the chances of the two strains of virus combining to mutate into a new form are high. Another worry for health officials is the potential for the avian virus to combine with a human flu virus in an intermediary sources like a pig. Already pigs in Java, Indonesia, have tested positive for H5N1.
Last month influenza experts noted a potentially menacing changes in the avian flu virus in Vietnam. Human cases of bird flu in northern Vietnam were found to show an epidemiological pattern and virological features different from those seen in the 2004 cases. They also differed from those currently seen in human cases in southern Vietnam and other Asian countries. These differences could indicate that the virus might already have been transmitted from human-to-human, though this is not proven as yet.
http://www.indianexpress.com/print.php?content_id=70922
Pallavi Aiyar
Bejing, May 23 Bird flu has once again raised its deadly head in mainland China. The Chinese Ministry of Agriculture has confirmed that the deaths of 178 migratory birds in the country’s Northwest Qinghai province, have been caused by the avian influenza known as H5N1.
For health experts, this is further confirmation that the virus is now endemic in Asia and many say that it’s not a question of if, but when, the H5N1 mutates into a form that would enable it to spread between humans.
Despite fervent measures to contain the virus since it first appeared in late 2003, including the slaughtering of tens of millions of birds and vaccinating many more, bird flu has continued to spread in Asia. The prospects of eliminating the virus within the next few years now appear to be virtually nil.
‘‘Elimination is a strategy we are no longer looking at,’’ say Maria Cheng, spokesperson for the World Health Organisation (WHO) in Beijing. ‘‘The flu is now established in the region so that eliminating it is not a good possibility.’’ Health experts are trying instead to focus on containment, including the monitoring and vaccination of animals.
Bird flu has affected 11 countries in the region from Japan to Indonesia and WHO says the outbreak is without precedent.
Avian influenza already fulfills 2 out of the 3 conditions for causing a human flu pandemic: the emergence of a new virus to which humans have little or no immunity and the ability of this virus to replicate in humans. The third condition, that the virus must be transmittable from one human to another, is the one standing between the current situation, where the flu is by and large limited to poultry and a possible world wide human flu pandemic of staggering proportions.
Currently, H5N1 is only known to spread between birds and, more rarely, from birds to humans. But as the virus continues to spread there is a distinct possibility that it will mutate in time, enabling human to human transmission.
Says Cheung, ‘‘We have a situation at the moment where both the human influenza virus and avian flu virus are circulating in a region simultaneously.’’
If H5N1 infects a human who is also carrying a human flu virus, the chances of the two strains of virus combining to mutate into a new form are high. Another worry for health officials is the potential for the avian virus to combine with a human flu virus in an intermediary sources like a pig. Already pigs in Java, Indonesia, have tested positive for H5N1.
Last month influenza experts noted a potentially menacing changes in the avian flu virus in Vietnam. Human cases of bird flu in northern Vietnam were found to show an epidemiological pattern and virological features different from those seen in the 2004 cases. They also differed from those currently seen in human cases in southern Vietnam and other Asian countries. These differences could indicate that the virus might already have been transmitted from human-to-human, though this is not proven as yet.
http://www.indianexpress.com/print.php?content_id=70922