Hong Kong flu still poses pandemic threat.

WASHINGTON—In December 1997, news watchers were confronted with sobering images of government workers in Hong Kong slaughtering 1.4 million chickens in a massive effort to prevent avian influenza from spreading through the densely populated city and, potentially, across the globe. Earlier that year, what was later identified as a strain of influenza previously known to infect birds, but not people, had sent 18 patients to Hong Kong hospitals. The first case led to the death of a 3-year-old boy, followed by the deaths of five other patients. Somehow the virus had jumped species. Working with the US Centers for Disease Control and Prevention (CDC), Hong Kong health officials began implementing a control plan designed to obviate such drastic measures in the future. It didn’t. In June 2001, and again in May 2002, a total of 4 million chickens in Hong Kong were destroyed to stanch potential pandemics. Both cullings were precipitated by detection of influenza virus in Hong Kong poultry, said John Siu-Lun Tam, PhD, a professor of microbiology at the Chinese University of Hong Kong, during a scientific session at the meeting of the World Medical Association held here in October. And although angst over the specter posed by bioterrorism dominated the meeting, a CDC official warned that the threat of an influenza pandemic is still “very real.” Such a worldwide outbreak would dwarf the influenza epidemics that sweep through the United States every winter, said Nancy Cox, PhD, chief of the influenza branch of the National Center for Infectious Diseases at the CDC. While a typical flu season claims about 20000 US lives annually, a pandemic could provoke 207000 deaths, 734000 hospitalizations, and 42 million outpatient visits, estimated Cox and CDC colleagues Martin Meltzer, PhD, and Keiji Fukuda, MD (Emerg Infect Dis. 1999;5:659-671). “It would be extremely overwhelming,” said Cox.