Large numbers of dying birds and an unusual cluster of human cases were at first viewed as separate events. 2). This finding was significant in implying that, if the virus was St. Louis encephalitis, it was killing birds and possibly could be connected to the human outbreak. The lessons we identified related primarily to addressing possible needs in five areas: local surveillance and response capabilities, communication among public health agencies, coordination between public health and animal health efforts, capabilities of laboratories, and efforts to distinguish between natural and unnatural events. The Local Disease Surveillance and Response System Is Critical

The West Nile outbreak provided a number of lessons about surveillance. Many Aspects of Surveillance and Response Worked Quickly and Well

The human outbreak of West Nile began with a few unusual cases. A 1999 assessment by the Institute found that disease surveillance systems in place at local, state, and federal levels rely on systems of disease reporting from health providers that are notorious for their poor sensitivity, lack of timeliness, and minimal coverage.Because an effective medical response to a bioterrorist event would depend in part on the ability of individual clinicians to identify, accurately diagnose, and effectively treat diseases (including many that may be uncommon), the Institute reported that education about the threat posed by bioterrorism and about the diagnosis and treatment of various agents deserves priority. Better Communication Is Needed Among Public Health Agencies

Experts consider rapid and reliable communication among public health agencies to be essential to bioterrorism preparedness and coordination. While a secure electronic communication network was in place at the time of the initial outbreak, not all involved agencies and officials were using it at the time. Links Between Public and Animal Health Agencies Are Becoming More Important

The West Nile events illustrate the value of communication between public and animal health communities, the latter including those dealing with domestic animals, wildlife, and other animals such as zoo animals. For example,
Some key public health officials, such as the city health department’s Director of the Bureau of Communicable Disease, indicated that they were not aware of the similarities in the clinical symptoms occurring in the birds and humans until many days or weeks after the human outbreak began. The California researcher who conducted some of the diagnostic laboratory work on the West Nile outbreak was brought in by officials at New York State’s Department of Health because they learned of the innovative research his laboratory was developing to quickly and accurately identify the viral causes of unexplained deaths from encephalitis.Some involved officials indicated that the California laboratory’s involvement was fortuitous in allowing a laboratory not consumed with diagnostic testing for the outbreak to focus on performing the types of tests required to eventually identify the virus. Finally, the outbreak and surrounding events support public health officials’ views that bioterrorism preparedness rests in large part on the soundness and preparedness of the public health infrastructure for detecting any disease and the causes of disease outbreaks. With this information, we developed a chronology and compiled a list of lessons learned from the West Nile virus outbreak. Officials and agencies contacted included the following:
U.S. Department of Health and Human Services, Office of Emergency
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
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 To gather background information and relevant literature on the West Nile outbreak, West Nile virus, and surveillance activities put in place since the outbreak, we searched academic journals and news media and performed an extensive review of publications related to the virus. When the cause of an outbreak is unknown, it is much more difficult to respond quickly and effectively. 1 (Jan. 1, 2000), p. 12. 6, No. 8-17. 5, No.
Why GAO Did This Study

Pursuant to a congressional request, GAO provided information on the West Nile virus outbreak, focusing on: (1) establishing a thorough chronological account of the significant events and communications that occurred, from doctors and others who first saw the symptoms and from the officials mounting a response; and (2) identifying lessons learned for public health and bioterrorism preparedness.

What GAO Found

GAO noted that: (1) the analysis of the West Nile virus outbreak began as two separate investigations--one of sick people, the other of dying birds; (2) on the human side, the investigation began quickly after a physician at a local hospital reported the first cases, and the original diagnosis, while incorrect, led to prompt mosquito control actions by New York City officials; (3) the ongoing investigation involved the combined efforts of many people in public health agencies and research laboratories at all levels of government; (4) a consensus that the bird and human outbreaks were linked, which was a key to identifying the correct source, took time to develop and was initially dismissed by many involved in the investigation; (5) when the bird and human investigations converged several weeks after initial diagnosis, and after laboratory research was launched independently by several of the participants to explore other possible causes, the link was made and the virus was correctly identified; (6) there are several key lessons that emerged from the investigation and response to this outbreak; (7) the local disease surveillance and response system is critical; (8) in this outbreak, many aspects of the local surveillance system worked well, in that the outbreak was quickly spotted and immediately investigated; (9) assessments of the infrastructure for responding to outbreaks suggest that surveillance networks in many other locations may not be as well prepared; (10) better communication is needed among public health agencies; (11) as the investigation grew, lines of communication and decision-making were often unclear, and efforts to keep everyone informed were awkward; (12) links between public and animal health agencies are becoming more important; (13) the length of time it took to connect the bird and human outbreaks of the West Nile virus signals a need for better coordination among public and animal health agencies; (14) ensuring adequate laboratory capabilities is essential; (15) even though this was a relatively small outbreak, it strained resources for several months; (16) because a bioterrorist event could look like a natural outbreak, bioterrorism preparedness rests in large part on public health preparedness; and (17) the ensuing investigation and post-outbreak assessments illustrate the challenges in identifying the source of an outbreak, supporting public health officials' views that public health preparedness is a key element of bioterrorism preparedness.