Confirmation of Sustained H5N1 Transmission in Pakistan
Recombinomics Commentary 2:14
December 28, 2007
Citing information from Pakistan's health ministry, John Rainford, a WHO spokesman in Geneva, identified the man as a 25-year-old from the Peshawar area who became ill on Nov 21, was hospitalized Nov 23, and died Nov 28.
"He is the third of four brothers who developed proven or suspected pneumonia with illness onset dates between 29 October and 21 November," Rainford told CIDRAP News. "The brothers provided care for one another and had close personal contact in both the home and hospital."
According to previous reports, the family group was among eight people in Pakistan's North-West Frontier province, near the Afghan border, who were previously diagnosed with avian flu on the basis of preliminary tests in Pakistan. The eight included four brothers and a cousin from the same family, plus three other people. Another brother also had a flu-like illness but died without being tested.
The other patients who tested positive have been described as a man and his niece who were involved in poultry culling, plus a male farm worker.
Although the WHO Pakistan situation update did not contain the critical dates, the above CIDRAP report provides some of the key information to demonstrate sustained human-to-human (H2H) transmission through multiple generations in Pakistan. The above information indicates the index case developed symptoms October 29. Media reports indicate the first fatality died November 19, suggesting his disease onset was well into November. The second fatality developed symptoms November 21, providing an H2H2H transmission chain of index case to first fatality to second fatality. However, there were two other brothers and cousin with symptoms, so the chain may have additional internal links. The above description does not include the two health care workers, who are still questionable.
In addition to the large cluster, the small cluster of a man and his niece may represent another H2H cluster. The above discussion does not include their disease onset dates.
Thus, the above large cluster appears to be represent the most sustained H2H H5N1 transmission chain reported to date, but the sample handling is nothing short of an major disaster. The samples from most of the cases, which were positive cases based on clinical and epidemiological data, have not been lab confirmed by NAMRU-3 or Mill Hill due to sample collection after the start of Tamiflu treatment, sample degradation due multiple tests involving freeze / thaws, packaging and shipping issues, coupled with reporting delays and a lack of transparency.
These false negatives and lack of transparency continue to increase pandemic concerns.
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