Spring 2004 Issue
How CDC Protects Travelers in an Ever-Shrinking World
Planning a trip? If you’re among the millions of Americans who travel internationally each year, you’re at a higher risk for infectious diseases than ever before. Travel is shrinking the globe, making it possible for dangerous diseases to trek the world at warp speed. And left unchecked, today’s emerging diseases can rapidly become the endemic diseases of tomorrow.
Marty Cetron, M.D., EIS ‘92, deputy director of CDC’s Division of Global Migration and Quarantine (DGMQ), is all too familiar with health threats to mobile populations like international travelers, immigrants, refugees and migrant workers.
“It now takes just 36 hours to travel anywhere in the world. That is shorter than the incubation period for many diseases, which creates new challenges,” says Cetron. “People who are asymptomatic can travel rapidly and break out with their illness at their final destination. Or people who are sick can travel and relocate disease rather abruptly. Diseases of the global village are literally one plane ride away.”
Among its many responsibilities, DGMQ oversees the screening of arriving international travelers for symptoms of illness that could be significant to public health; provides travelers with essential health information through publications and the Internet; enforces entry requirements for certain animals and insects; and collects and disseminates data about outbreaks affecting travelers worldwide.
Resources for international travelers
CDC’s Travelers’ Health Web site (www.cdc.gov/travel) is consistently one of the agency’s busiest sites, with an average of 10,000 to 20,000 visits a day, and well over 6 million visits annually. Prospective travelers using the site can learn about recommended vaccinations and preventive health measures, changes in vaccine requirements and drug availability, and the most recent disease outbreaks and emerging infections.
Another popular resource for health-related travel information is the Health Information for International Travel publication, better known as the “Yellow Book.” Geared for health care workers, the Yellow Book serves as the “gold standard” in travel health medicine - both in the United States and abroad. Produced every two years, and updated online periodically, the book provides readers with current recommendations for vaccinations required for travel to various countries, as well as critical information about prevention of illness and injury. The Yellow Book is also available in an interactive, online format (www.cdc.gov/travel/yb).
Through a partnership with the CDC Foundation and an educational grant from GlaxoSmithKline, DGMQ was recently able to significantly upgrade and enhance both the Web site and the Yellow Book.
“We’ve been able to sustain this important program because of our relationship with the CDC Foundation, and we want to continue to enhance it and make it more widely available in the future,” says Cetron.
Protecting our borders
In addition to making information available to travelers, CDC takes a proactive role in monitoring arriving travelers to the United States. CDC quarantine inspectors serve as important guardians of health at U.S. borders and ports of entry, routinely responding to illnesses in arriving passengers. CDC operates eight quarantine stations, based in international airports in New York, Chicago, Miami, Atlanta, Los Angeles, San Francisco, Seattle and Honolulu. Each of these stations is responsible for all ports, seaports, and international airports in its assigned region.
Cetron recalls a typical case for the quarantine inspectors involving a foreign exchange student diagnosed with meningococcal meningitis in Madrid, Spain. She had close contact with dozens of fellow exchange students, who were all boarding different flights on the same day to return to the United States.
“We got a call from an international partner on a Sunday afternoon with about an hour’s leeway before the first flight arrived, and maybe four hours until the last flight arrived. We immediately deployed our Quarantine Station staff to the appropriate international airports, got access to preventive antibiotics, permission from parents to treat kids who were minors, and lined up all our medical contacts in each of the areas. It was a huge effort.”
In addition to preventing small occurrences from turning into larger threats, Cetron’s staff also managed the recent wave of international disease outbreaks that threatened to enter the U.S. borders. “During the 2003 SARS outbreak, we increased our field staff from 35 to 125, and had a physical presence at 25 ports of entry,” says Cetron. “It became obvious as many emerging health threats came one after another – SARS, monkeypox, avian flu – that this is the ‘new normal.’ We’re now in the planning process of building a more robust presence at an expanded number of ports to respond to ongoing public health challenges.”
Tracking travel-related outbreaks worldwide
CDC scientists use the GeoSentinel network, a special network of clinics around the world, to monitor trends among travelers and other globally mobile populations. Made up of 26 clinics and more than 100 members, the Network is a crucial tool for communicating with health providers worldwide.
“Because we’re a relatively wealthy western country with a strong diagnostic infrastructure, travelers are often the ‘sentinels’ for outbreaks that may otherwise be silent in their countries of origin,” explains Cetron. “By maintaining good travel surveillance, we can often uncover outbreaks that have been brewing in other countries.”
Phyllis Kozarsky, M.D., chief of DGMQ’s travelers’ health section, recalls a strange illness that emerged among participants in the Eco-Challenge, an annual event held in Borneo that attracts adventure athletes from all over the world to race through wild terrain. “All of a sudden, our GeoSentinel sites in Toronto, London and New York were reporting an outbreak of high fever and chills among race participants. As it turns out, some of the participants had leptospirosis, a bacterial disease that contaminates water,” she says. “The water they had been exposed to had been infected by rat urine. Because we were tracking the trend, we were able to contact each of them and alert them to these symptoms and treatment.”
CDC can’t do it alone
Numerous collaborative partnerships at the federal, state, local and international level, as well as with the private sector and the media, play a critical role in protecting travelers and other mobile populations.
“Right now, we’re working extremely closely with the airline industry,” says Kozarsky. “Airlines are even more challenged by SARS than they were by 9/11, so they’re very interested in partnering with us to prevent transmission of illness on board. The Air Transport Association is working with us on how best to educate their air crew and their ground crew, as well as how to proactively educate passengers.”
CDC also works closely with international partners such as the World Health Organization (WHO) to reach consensus on travelers’ guidelines. “CDC and WHO are probably the most quoted sources of health information in the world, so we wanted to bring our guidelines in sync. We’ve established a working group that will meet periodically to ensure consistency,” says Kozarsky.
-Lisa Splitlog