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Very quietly, the World Health Organization today confirmed what most of us had suspected all along -- that the Pakistani H5N1 human cases among family members in October and November of last year were, indeed, "likely" victims of human to human transmission. 

In the April 3, 2008 Update 2, three of the four family members (all male) were confirmed to have contracted H5N1, and the fourth is unconfirmed but "probable".  It is unknown if chain H2H2H transmission occurred, but judging by the onset dates, it is quite reasonable to assume this event is also likely.

Here is the WHO report, and a massive hat-tip to Crof for publishing this on his blogsite, H5N1.  And here's another sigh of relief that we dodged the proverbial bullet once again. 

Will our luck continue to hold out until we get real-time, global surveillance?  No one on Earth can answer that one.

Avian influenza – situation in Pakistan - update 2

3 April 2008

Two additional H5N1 cases were confirmed by serological testing, thus providing final H5N1 infection test results on a previously reported family cluster in Peshawar.

These tests were conducted by the WHO H5 Reference Laboratory in Cairo, Egypt and the WHO Collaborating Centre for Reference and Research on Influenza in Atlanta, USA. The table below summarises the testing results of the confirmed/probable cases in the family cluster.

• The preliminary risk assessment found no evidence of sustained or community human to human transmission.
• All identified close contacts including the other members of the affected family and involved health care workers remain asymptomatic and have been removed from close medical observation.

These laboratory test results support the epidemiological findings from the outbreak investigation in December 2007, and the final risk assessment that suggested limited human to human transmission likely occurred among some of the family members which is consistent with some human-to-human transmission events reported previously. This outbreak did not extend into the community, and appropriate steps were taken to reduce future risks of human infections.

 

 

 

Relationship	Onset Date	Outcome	Exposure	Status
Case 1 (Index case)	29 Oct 07	Fully recovered	Direct contact sick/dead poultry	Confirmed (serology)
Case 2	12 Nov 07	Dead (19 Nov 07)	Close contact with Case 1, no known direct contact with sick/dead poultry	Probable (No sample available)
Case 3	21 Nov 07	Dead (28 Nov 07)	Close contact with Case 1 and 2, no known direct contact with sick/dead poultry	Confirmed (PCR)
Case 4	21 Nov 07	Fully recovered	Close contact with Case 1 and 2, no known direct contact with sick/dead poultry	Confirmed (serology)

http://www.who.int/csr/don/2008_04_03/en/index.html