The research suggests that few people are being infected by the strain, Siegel said. It would be unusual for this particular type of flu to mutate in a dangerous way that could cause it to become contagious between people, he said.
Philip Alcabes, a professor of public health at City University of New York's School of Public Health at Hunter College, cautioned that the findings do show that the strain infects people more easily than previously thought.
"Does this mean H5N1 is more or less of a threat to human health? Really, the report changes nothing in that regard -- because the public health concern about avian flu is about the possibility of future change in the virus-human relationship. With this study we know a little more about the present virus-human relationship -- but we still don't have a crystal ball," Alcabes said.
"So it remains important to understand how animal viruses, including H5N1 and others, circulate among animals and how they migrate to human populations," added Alcabes, who was not involved in the new study.
The analysis appears in the Feb. 23 online issue of Science.
For more on pandemic flu, try the U.S. National Library of Medicine.
SOURCES: Marc Siegel, M.D., associate professor, medicine, New York University,New York City; Philip Alcabes, Ph.D., professor, public health, City University of New York's School of Public Health, Hunter College, New York City; Feb. 23, 2012, Science, online
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