H5N1 Confirmed in Three New Egyptian Patients
Recombinomics Commentary
December 24, 2006
The WHO earlier said a brother, 26, and sister, 15, had the virus and then said a third relative, a woman aged 30, had contracted it.
All three are from the same extended family of 33 living in a single house in a village near the town of Zifta in Gharbiya province.
The above comments provide additional detail on the confirmed cases in the Egyptian family cluster, which has now grown to three. This is the largest cluster reported to date in Egypt. The location is 12 miles south of the case confirmed in October. The H5N1 sequence from that case had a number of newly acquired polymorphisms, including several from H5N1 reported in neighboring countries.
One of the acquisitions, M230I, matches the receptor binding domain sequence in the three human strains, H3N2, H1N1, and Influenza B. The Influenza B match is for positions 226-230 (QSGRI). Since influenza B is efficiently transmitted from human-to-human, the presence of M230I in the Qinghai strain of H5N1 is cause for concern.
The confirmed cluster in Gharbiya province may grow into a larger geographical cluster. In addition to the four confirmed cases this season, Arab language reports in Egypt describe two additional patients hospitalized in Tanta, the capital of Gharbiya province and about 15 miles from the four confirmed cases.
Gharbiya has been recently called an H5N1 hot spot. It is in the Nile Delta and lies within major migratory bird flyways, as do most of the countries in the Middle East.
Turkey has reported the deaths of chickens and sparrows. Iran has begun to cull sick chickens. Although neither country has reported H5N1 this season, last year Egypt reported H5N1 in a teal, while Iran has published the sequence of a whooper swan isolated last season.
The confirmation of the largest cluster in Egypt mirrors the largest cluster in Turkey last year. Infections in both clusters began in December, and signaled a new season of human H5N1 cases. These cases had several changes in the receptor binding domain that increased affinity to human receptors. These changes were also linked to larger clusters, as has been confirmed in Egypt.
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