MEMPHIS, Tenn., October 9, 1997 -- A new influenza virus, first found in a now-deceased Hong Kong boy in May and against which the human immune system is defenseless, passed directly and most unusually from poultry to the boy, reported Robert G. Webster, Ph.D., chairman of the St. Jude Children's Research Hospital Department of Virology and Molecular Biology, and other scientists in an article published today by Nature.
"Typically, new influenza viruses pass through and are genetically modified in other mammals, like pigs, before reaching humans. A unique feature of this new virus of the H5 subtype found in Hong Kong, which we call HK97, is that it managed to cross the avian-human species barrier without prior adaptation in another mammalian species," said Dr. Webster.
Previously, only influenza viruses of the H1, H2 or currently circulating H3 subtypes have been shown to cause influenza in humans. It is not known how the Hong Kong boy was infected with the H5 virus. There was an avian flu epidemic a month earlier.
"Fortunately, there are no indications that more infections with HK97 have taken place in humans or that the virus has spread amongst humans, so HK97 does not seem to be a direct pandemic, or world epidemic, threat at present. However, its emergence illustrates the necessity for global influenza surveillance," said Dr. Webster.
According to a U.S. Department of Agriculture report, more than 460 blood samples were taken from people exposed to the boy and another 1,900 samples were taken from people showing flu symptoms, with none revealing new cases of HK97.
The Center for Disease Control (CDC) in Atlanta is developing a lab test for detecting the new virus, and the CDC Advisory Committee on Immunization Practices is scheduled to discuss HK97 when it meets on October 22-23.
Note: Dr. Robert Webster will be available to answer questions from the media on October 8, 1997, 2:30 pm to 3:30 pm, CDT, via teleconference at 800.289.0730. The conference will be replayed for interested listeners beginning 5:30 pm, CDT, October 8, 1997, and continuing for one week until October 15, 1997, by calling 888.566.0825.
St. Jude Children's Research Hospital, in Memphis, Tenn., was founded by the late entertainer Danny Thomas. The hospital is an internationally recognized biomedical research center dedicated to finding cures for catastrophic diseases of childhood. The hospital's work is primarily supported through funds raised by the American Lebanese Syrian Associated Charities (ALSAC). All St. Jude patients are treated regardless of their ability to pay. ALSAC covers all costs of treatment beyond those reimbursed by third party insurers, and total costs for families who have no insurance.
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Journal
Nature