James Martin Center for Nonproliferation Studies
Combating the spread of weapons of mass destruction with training & analysis

CNS Reports

29 November 2000

Even though the United States has the most extensive disease surveillance and response system in the world, there are gaps in its ability to detect outbreaks early, as the 1999 West Nile virus outbreak illustrated.

Whether a threat results from a natural outbreak of an unknown pathogen or the deliberate use of disease by terrorists, animals might be sentinels of a hazard that could affect humans. In the West Nile case, dead birds flagged the disease outbreak. But critical links between officials dealing with animal and human health did not exist or were not effective.

The U.S. public health surveillance system could benefit from increased communication between animal and human disease surveillance systems-including improved protocols to integrate response, established networks of communication across jurisdictions and levels of government, and improved laboratory capabilities for animal pathology. In 1999, West Nile virus appeared in birds and humans in New York. This was the first evidence of West Nile in the United States. Incorrectly diagnosed for several weeks, the virus spread throughout the Northeast. Because the virus was originally thought to be St. Louis encephalitis, also transmitted by mosquitoes, prompt and aggressive mosquito-eradication programs significantly limited the epidemic.

During the time it took health officials to link dying birds to human cases, however, another disease-possibly transmitted person-to-person-might have spread much more rapidly, causing more deaths. In that scenario, the eradication programs successfully employed in New York might have been useless.

Although interest in biological agents appears to be increasing, there have been very few incidents of bioterrorism in the United States-leaving very limited empirical data upon which to base policy. One notable case occurred in 1984 in Oregon, when the Rajneesh cult contaminated salad bars with salmonella-sickening some 700 persons-in an effort to influence the outcome of a local election. To show how a robust public health system can effectively respond to bioterrorism, we can look to the way our health system responds to natural outbreaks.

When a disease appears in the population, the public health system must be able to identify the disease, make appropriate linkages among jurisdictions to assess the magnitude of the epidemic, and implement an effective control plan.

These responsibilities require rapid, regular and effective communication across jurisdictions and levels of government. In addition, this task may involve expertise from a range of disciplines, including veterinarians. In the West Nile case, for example, the virus showed up in animals before moving to humans.

This task must also be front-loaded: Policies, planning, and training must focus on early detection and surveillance. As an analogy, consider how people undergo regular medical examinations in an effort to detect life-threatening illnesses such as cancer or heart disease. No matter how good our response capabilities are, diagnosing the problems early is critical for effective treatment.

The sheer size of this country and the number of jurisdictions make it hard to establish clear and effective lines of communication among public health departments and across local, state and federal jurisdictions. In addition, as the experience with West Nile illustrated, protocols for addressing the emerging epidemics are poorly understood, particularly between animal and human health professionals. Efforts must be made to make sure that the various players know these protocols and are willing to use them.

Over the past few decades, the U.S. public health system has deteriorated.

This is especially true of laboratory capabilities. Currently, few labs nationwide can perform tests at the level required to address new and emerging human and animal pathogens, be they the result of increased globalization or bioterrorism. Upgrading this laboratory capability is essential to bolstering defenses against disease outbreaks in this country.

Experiences such as West Nile make for useful but hard lessons. Early problems between local and federal officials contributed to the delay in accurate identification of the virus. The public health system's response was quite solid once the critical linkages and diagnoses were made. But that response could have come more rapidly. By strengthening a few mechanisms-such as communication networks among health departments and veterinarians, as well as augmented laboratory capabilities-the United States can better prepare itself for any disease catastrophe resulting from natural causes or a terrorist attack.

Jason Pate is manager of the Chemical, Biological, Radiological and Nuclear Terrorism Database at the Chemical and Biological Weapons Nonproliferation Project at the Monterery Institute of International Studies.