Info

Notes: Airports participating in the Airports Council International annual traffic statistics collection. Total passengers enplaned and deplaned; passengers in transit counted once.

Source: Airports Council International. (2005). Passenger Traffic 2004 FINAL. Retrieved from: http://www.aci.aero/cda/aci/display/main/aci_content.jsp? zn=aci&cp=1-5_9_2_, with permission.

Notes: Airports participating in the Airports Council International annual traffic statistics collection. Total passengers enplaned and deplaned; passengers in transit counted once.

Source: Airports Council International. (2005). Passenger Traffic 2004 FINAL. Retrieved from: http://www.aci.aero/cda/aci/display/main/aci_content.jsp? zn=aci&cp=1-5_9_2_, with permission.

but also has potential as a method for estimating disease activity in another country. We expect the above practices to become more routine with time.

The need for biosurveillance of air travel is increasing due to the ever increasing volume of air travel, especially international travel. In 2004,1.275 billion passengers enplaned and deplaned in just 30 large airports alone (Table 12.3). Airports Council International projects a 4% growth rate in air travel resulting in 7.4 billion passenger trips by 2020 from a current level of approximately 1.7 billion (Airports Council International, 2005). Biosurveillance personnel must consider an outbreak anywhere in the world as a threat—especially to those cities that serve as major hubs for international travel. The WHO plays a key role in disseminating information about outbreaks that pose international health, as we discuss below.

Public mass transit accounts for a substantial proportion of daily commuters in many cities around the world, including several metropolitan areas in the United States. The New York City subway system alone carries 5 million passengers every workday; eight of ten commuters arriving in Manhattan daily do so by train. The Washington, D.C. Metrorail is carrying nearly 700,000 commuters per day. A subway train of 10 cars operating at rush hour may carry over 2000 passengers.

Gershon and colleagues reviewed the health and safety hazards, whether natural or manmade, associated with subways (Gershon et al., 2005). The combination of high transient population density, restricted air circulation/filtration, and confined spaces creates an opportunity for terrorists to effectively expose large numbers of people to biological or chemical agents.

The vulnerability of subway infrastructure to bioterrorism has been recognized for decades. According to an unclassified U.S. Army report, "A series of trials were conducted in three major north-south subway lines in mid-Manhattan, New York City, in June 1966. A harmless simulant biological agent (Bacillus globigii) was disseminated within the subway tubes and from the street into the subway stations. The simulant data when translated into equivalent covert attacks with pathogenic agents during peak traffic periods indicated that large numbers of people could be exposed to infectious doses" (U.S. Department of the Army, 1977). In 1995, this credible scenario became reality when the Aum Shinrikyo successfully dispersed sarin gas on the Tokyo subway injuring 5500 and killing 12 (Okumura et al., 2003). Two other chemical agent releases in subway and railway station restrooms were thwarted that year (Okumura et al., 2003). In addition, the Aum Shinrikyo attempted to disperse anthrax in the Tokyo subway, but, fortunately, they used the vaccine strain of anthrax which does not cause disease (Keim et al., 2001).

There is little published information about air monitoring of subway systems. At present, we are aware of pilot projects in one or more U.S. subway systems that directly monitor the air for pathogens and plans to deploy this capability more widely (Telemedicine & Advanced Technology Research Center, U.S. Army Medical Research & Materiel Command, 2004).

Was this article helpful?

0 0

Post a comment