Contributed by Lisa Olen| 14 March, 2005 15:29 GMT
'Such cases can provide the first signal that the virus is altering its behavior in human populations and thus alert authorities to the need to intervene quickly.'
The latest attacks of avian influenza (bird flu) in Vietnam have renewed concerns among World Health Organization officials that the virus may have developed the ability to spread from human to human. A cluster of cases in Thai Binh province that affected members of a family and two health workers who attended one of them have raised the alarm level.
It is the ability fo spread easily among populations that could trigger the much-feared, but expected, worldwide flu pandemic.
The deadly H5N1 bird flu virus has killed 47 people in Asia so far.
Additional 10 Cases Confirmed in Vietnam
The Ministry of Health in Vietnam on Friday confirmed an additional 10 cases of human infection with H5N1 avian influenza, WHO reports. Some of those cases were detected in March, but the notification also includes some older cases that date back to late January. Of the newly reported cases, three have been fatal.
The total number of laboratory-confirmed cases in Vietnam detected since mid-December 2004 now stands at 24, 13 of which have been fatal.
Virus May Be Altering Its Behavior
The collection of full information on new cases, including those that may be closely related in time and place, is critical to ongoing assessment of the pandemic risk posed by the H5N1 virus, emphasizes WHO.
Getting investigators into the field quickly to determine the details of each new case is essential to ensure timely detection of clusters of cases occurring in family members or health care workers, WHO notes.
"Such cases can provide the first signal that the virus is altering its behavior in human populations and thus alert authorities to the need to intervene quickly," says WHO.
Bird Flu Progress Since January 2004
The first human cases of H5N1 infection, linked to poultry outbreaks in parts of Asia that have been ongoing since December 2003, were reported in January 2004 in VietnNam and Thailand. Since then, 69 cases have been reported in total, of which 46 were fatal.
Human cases have occurred in three phases: from January through March 2004 (35 cases, 24 deaths), from August through October 2004 (9 cases, 8 deaths), and from December 2004 to the present (25 cases, 14 deaths).
In the present phase, the total includes a single case in Cambodia, which was fatal, in addition to those in Viet Nam.
Click here to view a chart showing the cumulative number of confirmed human cases of avian influenza A/(H5N1) since January 28, 2004. |
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