Fatal Cambodian Bird Flu Case Officially Confirmed
Recombinomics Commentary
February 5, 2005
>> Previous reports have hinted at serious respiratory disease in household contacts of the deceased, and her younger brother, who died from pneumonia prior to her admission to hospital, was retrospectively assumed to have been an avian influenza case. However, the above report, although still preliminary, provides no evidence of onward human-to-human transmission of the virus.<<
The confirmation of H5N1 in the 25 year old deceased patient and the negative test result for her living family members creates a cluster history that is virtually identical to 8 prior familial clusters in Vietnam and Thailand.
The Cambodian case is only unique by virtue of the location of the infections and the export of the Cambodian case to Vietnam. The sequence of events has become all too common. The index case has an exposure to dead or dying poultry. He (14M) develops symptoms of bird flu and dies. There is no sample collected and his cause of death is unclear. However, when a second family member develops the same symptoms a week or two after the index case, the suspicion level increases considerably and more urgent medical care is sought.
In the above case the 25F was taken to a local clinic in Cambodia which probably was not equipped to do sophisticated testing. The patient then was admitted to a larger more specialized facility in Vietnam, where samples were collected for further screening. After her death, she was found to be H5N1 positive and that result was confirmed by an outside lab.
The latest result creates a cluster that is remarkably like the 8 prior clusters. The onset dates are bimodal, at last one member of the cluster is laboratory confirmed H5N1 positive, the index case dies, and the secondary case dies, like 8 of the 10 secondary cases in the prior 8 clusters. Moreover there are no suspect or confirmed tertiary cases.
The cluster also shows that the likelihood of transmission from an index case to a family member is high and is significantly more likely than transmission from a bird to a person. Bird to human transmission remains quite rare, but once a family member becomes infected with H5N1, deadly consequences frequently follow if protection measures have not been followed.
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