Commentary
H5N1 Migration Into Northwest Pakistan
Recombinomics Commentary 17:09
June 24, 2008
"The 1st outbreak of highly pathogenic notifiable avian influenza (HPNAI) was reported in February 2007 while the last one was observed on 3 Mar 2008. The event involved a total of 225 238 commercial poultry of various categories. Stamping out policy was adopted. All poultry on the index farms were culled and disinfection operations were completed as per OIE guidelines. All culling and disinfection operations in the last reported outbreak were completed on 4 Mar 2008. All sero-surveillance results obtained within a 10-km (6 mi) radius zone around the outbreak were negative. Monitoring and sero-surveillance will continue.
Therefore, since no further outbreaks of HPNAI have been observed in the country since 3 Mar 2008, Pakistan declares itself free of HPNAI with effect from 4 Jun 2008".
If the current outbreaks are officially confirmed -- as they appear to be -- this is disappointing and a blow to the Pakistani poultry industry and indeed to the veterinary services which have, reportedly, invested considerable efforts and skill to control and eradicate the epizootic; the declaration of freedom above may have to be reconsidered. Possibly, the current event is due to the unstable situation along the borders with Afghanistan, allowing introduction of infected animals and their products, contaminated feed, etc.
Mod.AS
The above ProMED commentary describes the recently filed final OIE report from Pakistan, declaring itself H5N1 free, which was followed by the recent outbreak in Swabi. The above commentary was in response to media reports which described the outbreak, but made no mention of a possible role of Afghanistan, which has not reported H5N1 since early 2007.
In contrast, Pakistan has had multiple outbreaks in 2007 and 2008 and the final report indicated these outbreaks were due to wild birds. Thus, the ProMED commentary omits the epidemiology in the final report, and then speculates on a smuggling / trade connection, which appears to be based on no hard data.
This commentary represents a ProMED pattern which has been repeated again and again following the movement of H5N1 into long range migratory birds at Qinghai Lake in May, 2005 (clade 2.2). The spread to nature reserves in Russia and Mongolia in the summer of 2005 clearly established the role of migratory birds in the transport and transmission of clade 2.2 H5N1, which subsequently spread to 50 countries west of China, in Europe, the Middle East, Africa, and south Asia. In south Asia, clade 2.2.3 was widespread and reported in India, Pakistan, Afghanistan, and Iran in early 2006. Although the H5N1 in Pakistan and Afghanistan is similar, geographical groupings of H5N1 spread by wild birds have been common. Although all are clade 2.2, various geographic sub-clades have been note. In many instances, the groups, such as the H5N1 in Scotland, northern Germany, Denmark, and Sweden in early 2006 did not involve any reported poultry outbreaks.
Although Afghanistan and Pakistan outbreaks have involved poultry, the OIE final report from Pakistan covering outbreaks in 2007 and 2008 clearly indicates that the outbreaks are linked to wild birds. There is no mention of introductions via smuggling or trade, as implied, but not supported, in the ProMED commentary.
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