H5N1 Human to Human Tranmission in Pakistan Specifics?
Recombinomics Commentary
December 19, 2007
The eight individuals in Pakistan who are suspected to have bird flu probably have a combination of infections from poultry and limited person-to-person transmission from close contact, a top World Health Organization expert said on Tuesday. Keiji Fukuda, coordinator of WHO's global influenza program, said while unconfirmed, any human-to-human spread seemed similar to previous outbreaks in Thailand and Indonesia -- affecting close family members caring for sick loved ones.
The above comments confirm the data represented by the consensus media reports. However, these reports lack hard dates, including disease onset dates, which suggest the cluster may be the longest in term of links in the chain, as well as persistance of the chain. The metrics could raise concerns that the H5N1 in circulation will generate similar chains in Pakisitan, as well as downstream locations in Europe, the Middle East and Africa, which could generate unprescedented numbers of confirmed H5N1 cases.
Although Pakistan has not released any H5N1 sequence data from their poultry outbreaks in 2006 and 2007 (see satellite map), public 2006 sequences from adjacent Afghanistan and India have been published. These sequences have some similarities, and it is likely that earlier sequences from Pakistan are similar to those from neighboring countries. However, neither India nor Afghanistan have released sequences from reported outbreaks this year.
Sequences have been released by Krasnodar and Germany, and these sequences are related to 2006 sequences from Uva Lake. These Uva Lake sequences are also related to the earlier sequences from India and Afghanistan, so it is likely that the current sequences in Pakistan are also related to these Uva Lake sequences.
These sequences are widespread. The first appeared in Kuwait at the beginning of this year. Then they appear in multiple countries in Europe of the summer (Czech Republic, Germany, France). Similar sequences were the published from Krasnodar, and subsequent infections in England and Germany are also said to be similar, suggesting that recent outbreaks in Romania, Poland, Rostov, and Saudi Arabia are also similar.
Therefore the ability of these sequences to transmit human-to-human (H2H) is of broad interest, so prompt reporting of the specifics of the H2H transmission is important. The larger cluster includes the index case, four brothers, a cousin, and one or two health care workers. Media reports indicate this cluster began with exposure(s) during a cull on October 21-23. The index case developed symptoms on October 25, and two brothers died November 19 and 25. Moreover, a health care worker may still be hospitalized, suggesting the cluster may be H2H2H2H or longer and may have persisted for almost 2 months. In addition, media reports suggest there are three additional confirmed patients representing another familial cluster.
Local confirmation of the initial lab positives was projected to be completed yesterday, and disease onset dates for the cluster members should have been known for some time. This information is usually released in WHO situation updates, which give the age and gender of confirmed cases, as well as disease onset dates, hospitalization dates, and dates of death as well as relationships between cluster members.
Virtually all of the data has not been released even though the outbreak began almost 2 months ago, and WHO has been aware of this cluster for at least a week.
Yesterday, media reports described a new suspect case in Kuwait, which when coupled with the massive outbreaks in poultry in Saudi Arabia and the high concentration of pilgrims at the Hajj, create cause for concern.
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