Volume 11, Number 3—March 2005 Rumor Surveillance and Avian
Influenza H5N1 We describe the enhanced rumor surveillance
during the avian influenza H5N1 outbreak in 2004. The World
Health Organization’s Western Pacific Regional Office identified
40 rumors; 9 were verified to be true. Rumor surveillance
informed immediate public health action and prevented
unnecessary and costly responses. In January 2004, 14 persons in
Vietnam were admitted to provincial hospitals with severe
respiratory illness (1). Avian influenza H5N1 was detected in
samples from 3 of these patients. Health officials and the World
Health Organization (WHO) were concerned, as these were sporadic
cases of an influenza strain that normally infects birds
exclusively (2). Furthermore, little was known about the extent
of the outbreak, its potential for international spread, and the
possible evolution of a pandemic influenza strain. WHO issued an
international public health alert on January 13, 2004, to inform
the world about the outbreak (1). New