Pandemic Concerns and Transmission of Bird Flu in Thai Binh
Recombinomics Commentary
March 13, 2005
The hospitalization of a second health care worker in Thai Binh has raised concerns of more efficient transmission. The confirmation of the first health care worker generated a chain that involved at least two family members and a health care worker. The index patient developed symptoms February 14. His sister had symptoms on February 21, and his nurse developed symptoms on or about Feb 26.
The hospitalization of the second nurse extended the chain into March. Although there are reports of the second nurse testing negative, tests in Thai Binh have a history of initially being negative and the patient tests positive subsequently. It is not clear if this is due to an insensitive test in general, or changes in the genetic make-up of H5N1 that create problems for the detection test.
The most recent cluster of cases in Thai Binh have had patients that have been discharged or are improving, raising the possibility that the bird flu in the north is gaining in human-to-human transmission efficiency at the expense of a high case fatality ratio. The fatality rate has been at 100% in the cases in the south this season.
More testing on the second nurse as well as contacts of all of the confirmed or suspect cases would be useful. The high frequency of cases in Thai Binh would also suggest broader screening of hospital personnel, because of additional evidence of H5N1 in asymptomatic and milder cases.
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