Suspect H5N1 Familial Cluster in Vietnam and South Korea
Recombinomics Commentary
November 7, 2007
A 33-year-old man from South Korea died of pneumonia with bird flu-like symptoms in Vietnam's southern Can Tho city, local media reported Wednesday. The man named Lu Chin-chu, whose wife is from the city's Co Do district, died on Tuesday afternoon, 11 hours after being admitted to the Can Tho General Hospital, said Youth newspaper. Specimens from the patient are being tested for bird flu virus strain H5N1.
His father in South Korea is suffering from pneumonia with bird flu-like symptoms, according to his relatives in the city.
The above report of suspected bird flu among family members in southern Vietnam and South Korea raises more questions than it answers. Although reported transport of H5N1 via commercial airliner has been limited to exotic birds, transport of SARS CoV via airline accelerated the SARS outbreak in early 2002, and is a major red flag for the spread of infectious diseases in general.
Although neither case has been medically diagnosed, this is the time of year for new H5N1 cases in Vietnam and Korea. The explosion of H5N1 out of China was first reported in Vietnam and Korea in late 2003. In Vietnam the H5N1 was clade 1 and was followed by human cases in Thailand in 2004 and Cambodia in 2005. The first reported Cambodian case also died in southern Vietnam after travel for treatment. Recently, Vietnam has reported clade 2.3 (Fujian strain) H5N1 in waterfowl.
It is unclear if the fatal cases in southern Vietnam recently traveled there from southern Korea. In late 2003 the H5N1 reported in southern Korea was a genetic precursor for the clade 2.2 H5N1 that was reported in the spring of H5N1 at Qinghai Lake. Last year at this time the H5N1 in south Korea was in the same location (see satellite tracking of whooper swans from Mongolia) and was the Qinghai strain, which is transported and transmitted by migratory birds. In both 2003 and 2006, the outbreaks in southern Korea were followed by outbreaks in Japan.
However, to date there have been no reported H5N1 human cases in either country, other than low antibody titers in cullers.
More information on the two suspect cases described above would be useful, including disease onset dates and travel history.
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