is also the lead agency in HHS for bioterrorism preparedness. In nt years, the President and Congress have been increasingly concerned ut the threat of terrorists using weapons of mass destruction, including ogical agents.1 Part of CDC's National Center for Infectious Diseases, Bioterrorism Preparedness and Response Program is responsible for lic health preparedness for potential acts of bioterrorism. In fiscal year ), HHS received $278 million of the $10.2 billion in counterterrorism ies allocated to federal agencies. Of the HHS funding, CDC received roximately $155 million for bioterrorism preparedness programs in al year 2000, approximately $40 million of which is to be awarded to e and local health departments for surveillance, epidemiology, ratory, and communications.

Figure 2: Timeli

Animal Outbrea

ing the first recognized outbreak of West Nile virus in the United States,
ction of animals preceded the first human cases by at least 1 to 2
ths. Large numbers of dying birds and an unusual cluster of human
es were at first viewed as separate events. Gradually, as an increasing
ber of laboratories became involved to conduct further testing on
an, animal, and mosquito samples, the linkages became clear, resulting
he identification of the West Nile virus (see fig. 2). The scale of these
rts was substantial, involving participants around the country. Since the
of the outbreak, various local, state, and federal agencies have taken
ons to address the potential ongoing consequences of the virus's
oduction into North America.

Human Outbreak

June

Detecting We Overview

ough the chance that terrorists may use biological materials may increase over the next
de, conventional explosives and firearms continue to be the weapons of choice for
rists. Terrorists face considerable obstacles in developing biological weapons. See
bating Terrorism: Need for Comprehensive Threat and Risk Assessments of Chemical
Biological Attacks (GAO/NSIAD-99-163, Sept. 1999) and Combating Terrorism:
ervations on the Threat of Chemical and Biological Terrorism (GAO/T-NSIAD-00-50, Oct.
999).

The Animal Outb

st Nile: An

tbreak

The identification of a newly emerging infectious disease2 within months was due to the combined, considerable efforts of scores individuals and several agencies in the animal and the human pub fields and in academia. Here is an overview of the key events that Appendix II contains a more detailed chronology.

No one is sure exactly when or how birds became infected. By la veterinarian at an animal health clinic in the New York City borou

2Emerging infectious diseases include those whose incidence in humans has inc within the past two decades or threatens to increase in the near future.

ens had examined and treated several birds that appeared to have
yous system disorders, releasing those that survived. Reports of dead
s increased through July and into August. By mid-August, dead birds
e being sent to the wildlife pathologist at the New York State
artment of Environmental Conservation. The wildlife pathologist was
to determine that the birds were not dying from any of several
mon problems, but he could not identify a clear cause. By late August,
rinarians at the Bronx and Queens zoos had joined the effort to identify
disease, after several wild and caged birds died on zoo property.

nwhile, near the end of August, a specialist in infectious diseases in a
munity hospital in Queens noticed that the hospital had an abnormally
e number of suspected cases of encephalitis or meningitis (diseases
lving inflammation of the brain or spinal cord) and that several of the
ents had developed an unusual pattern of muscle weakness. When the
pital's doctors were unable to find a clear cause or an effective
tment, the specialist called the Bureau of Communicable Disease
in the New York City Department of Health. After a quick but careful
stigation, city health officials contacted the state health department
CDC for additional help. Blood and spinal fluid specimens from
›ital patients were rapidly tested at state and CDC laboratories. On
ember 3, CDC announced that the test results were positive for St.
s encephalitis, a virus known in the United States but never before
wn to occur in New York City. That same day, the city, assisted by the
and CDC, launched a massive campaign to prevent people from being
n by mosquitoes and to determine the extent of the St. Louis
phalitis outbreak.

in the next week, however, the State Department of Health obtained
t appeared to be conflicting test results for St. Louis encephalitis,
ng doubts among some health officials about whether the exact cause
e outbreak in humans had been determined. In addition, CDC officials
⚫ questioned by city and state health workers and the public as to
ther the deaths of large numbers of birds and the human encephalitis
s might be connected. Because St. Louis encephalitis had not been
vn to kill its bird hosts, CDC officials said they considered the two

The Two Res and More Lal Involved

rding to a New York City Department of Health official, these patients were initially ɔy different physicians, as commonly occurs in any hospital, and it was not until a infectious disease consultant reviewed their cases that the opportunity to see these its as part of a cluster presented itself.

ponses Converge poratories Become

outbreaks to be unrelated. The cause of the outbreak in birds re unidentified, and, to help identify it, the zoo veterinarians and t wildlife pathologist enlisted the help of federal veterinary labor the U.S. Department of Agriculture (USDA) and the U.S. Geolog (USGS). By mid-September, both laboratories concluded that th disease was caused by a virus, that it did not appear to be any s Louis encephalitis or other avian virus they had previously teste they had insufficient laboratory capabilities to identify it more s The USDA veterinary laboratory sent its virus samples to the CI laboratory for further analysis.

The test results in birds, along with repeated negative test result samples in the state health department laboratory, increased the some state health officials about whether the human disease ag been correctly identified as St. Louis encephalitis. On Septembe invited a visiting academic researcher from California to try out testing methods on tissue specimens from human patients. The week, a Connecticut agricultural laboratory involved in that stat mosquito surveillance reported isolating St. Louis encephalitis v both a dead bird and mosquitoes collected near the outbreak ar finding was significant in implying that, if the virus was St. Louis encephalitis, it was killing birds and possibly could be connecte human outbreak.

At about the same time, CDC had begun testing and retesting m bird, and human specimens against a wider variety of flaviviruse to rule out the possibility of another closely related virus. Indep the head pathologist at the Bronx Zoo gained agreement from th Army Medical Research Institute of Infectious Diseases to attem identify the virus in birds.

Beginning on September 23, the academic researcher and CDC c same general conclusion: the virus causing the outbreak was no encephalitis but, rather, a virus that had never before appeared i United States. By the week of September 27, CDC had confirme "West Nile-like" virus was responsible for both the animal and th outbreaks.

e effort involved in addressing these outbreaks and identifying the cause
s concentrated and considerable. Hundreds of reported potential human
ses were investigated to determine whether West Nile was the infecting
us. By the end of the investigation, health officials confirmed 62 cases of
est Nile virus, including 7 people who died. Thousands of bird deaths
re similarly investigated by several state and federal laboratories and
encies, to determine how far the virus had spread. In addition to the
oratory investigations, state and local emergency management teams
re mobilized to respond to public health concerns. They managed the
ordination of conference calls and other communications, the
ablishment of hotlines to address the general public's concerns, and the
ocurement, distribution, and application of pesticides. The New York
y and State Departments of Health also developed fact sheets for the
blic on each of the pesticides in 1999, and in 2000 they implemented a
veillance system for health effects from pesticides. Table 1 shows some
ecific examples of the case surveillance and laboratory workload
perienced by some of the involved agencies during and since the
tbreak. Not all of the agencies involved have developed cost estimates
their efforts. As one indication of the cost, however, New York State
icials estimated that the state, city, and four counties in the area spent
re than $14 million on protective measures such as mosquito control
m late August through October.

Table 1: Example
West Nile Outbre

Agency
New York City
Department of Hea
New York City

New York State Hea Department (includi counties outside of York City and New Y State Department of Agriculture and Mark

New York Departmen Environmental Conservation, Albany, N.Y.

CDC's Division of Vector-Borne Infectiou Diseases,

Fort Collins, Colo.

U.S.Geological Surve National Wildlife Heal Center, Madison, Wis

City Department of Health conducts surveillance for pesticide-related morbidity by itoring calls to the Department's Poison Control Center.

GAOMEHS-00-180 West Nile Virus Outbreak