We interviewed officials in the public and private sectors at the national, tate, and local levels, and, to the extent it was made available to us, we btained relevant documentation from them. With this information, we developed a chronology and compiled a list of lessons learned from the West Nile virus outbreak. To some extent, the chronology was based on fficials' recollections of the specific events occurring on particular dates. When information provided by agencies or officials was inconsistent, we ssessed its relevance to our reporting objectives, sought any needed orroboration from other involved officials, and incorporated the formation accordingly. Officials and agencies contacted included the ollowing:

U.S. Department of Health and Human Services, Office of Emergency
Preparedness

Centers for Disease Control and Prevention, National Center for
Infectious Diseases, Division of Vector-Borne Infectious Diseases,
Division of Viral and Rickettsial Diseases, Division of Bacterial and
Mycotic Diseases

Central Intelligence Agency

U.S. Department of Agriculture, Animal and Plant Health Inspection Service

U.S. Geological Survey, National Wildlife Health Center

U.S. Army Medical Research Institute of Infectious Diseases

New York State Department of Health

New York State Department of Environmental Conservation

New York City Department of Health

New York City Commissioner's Office of Emergency Management
Wildlife Conservation Society/Bronx Zoo

Flushing Hospital Medical Center

Connecticut Agricultural Experiment Station

University of California at Irvine

Association of Public Health Laboratories

National Association of County and City Health Officials

a ProMED moderator active during the initial outbreak

› gather background information and relevant literature on the West Nile itbreak, West Nile virus, and surveillance activities put in place since the itbreak, we searched academic journals and news media and performed extensive review of publications related to the virus. We performed a milar review to identify reports and literature related to the preparedness the public health infrastructure for a bioterrorist event.

GAO/HEHS-00-180 West Nile Virus Outbreak

We also reviewed assessments of the response to the West Nile prepared by various agencies. These assessments both describ of these agencies on lessons learned and outline the steps they and policies they have implemented since the initial outbreak.

eak, 1999

me is of the essence in responding to an outbreak of an infectious
sease. When the cause of an outbreak is unknown, it is much more
fficult to respond quickly and effectively. As can be seen in the following
ronological table of events, the key to rapidly identifying and responding
the West Nile virus outbreak lay in merging efforts and information from
parate investigations of outbreaks in animals and humans. At the same
ne, as the number of participants increased, so did the complexity and
fficulty of communication and coordination. Looking back on the
tbreak of the fall of 1999 provides an opportunity not only to review the
gnificant investigative and laboratory work of a myriad of participants
ad the contributions of each toward the final diagnosis of the virus, but
so to analyze the communications and actions of the responding
overnment agencies in order to improve the nation's preparedness for
ture outbreaks, including ones not due to natural causes. Table 2
ovides a detailed chronology of significant actions and events.

(Continued From Date

Sunday, 8/15/99

Monday, 8/16/99

Tuesday, 8/17/99

Wednesday, 8/18/9

Thursday, 8/19/99

(Approx. date) Nassau County, N.Y., highway crew brings Flushing Hospital admits an elderly patient