West Nile Virus Outbreak:

Lessons for Public Health Preparedness

HEHS-00-180: Published: Sep 11, 2000. Publicly Released: Sep 11, 2000.

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William J. Scanlon
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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.

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.

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