Communicable diseases used to be stay-at-homes, but increased airplane travel has given them a ticket to ride around the world. In addition, illnesses we thought had been eradicated are making surprise visits with immigrants from less medically advanced countries.
By RANDOLPH FILLMORE
© St. Petersburg Times, published February 9, 2000
Germs know no borders. They travel freely, without airline tickets, passports or luggage.
"Any tourist mecca is an open door. The potential for arriving viral and bacterial agents and parasites is a worrisome problem," says Dr. Marc J. Yacht, director of the Pasco County Health Department.
Take tuberculosis. Once confined to the waste bin of infectious diseases, TB is back. More worrisome than plain old TB is globe-trotting drug-resistant TB. It defies even the four-drug combination that once knocked it out. This strain of TB could soon be rampant in American cities, much of it carried in by folks from eastern Europe (especially Russia and Estonia) and Central America, where treatment is poor.
Last October, the Open Society and Harvard Medical School published a joint alert warning that "strains of drug resistant TB are spreading rapidly and threaten to spiral out of control." Russia and Estonia were noted as "hot spots," contributing to the spread into North America through increased air travel.
The Harvard report cautioned that increased international migration and travel are multiplying the cases of TB in industrialized countries. Infected people can and do travel.
In 1994, an airline passenger with active TB traveled from Honolulu to Chicago to Baltimore and made the return trip to Honolulu a month later. When investigators from the U.S. Centers for Disease Control and Prevention found out, they scurried to identify the 925 passengers and crew from all the flights.
In what has since become a heroic piece of detective work, the CDC tracked down 86 percent of those on the flights and tested them. On the flight from Honolulu, 11 people became infected. On the return flight, 15. The CDC found that passengers seated within two rows of the carrier were most likely to be infected. Close proximity to the carrier and a longer flight raise the risk.
"This experience shows that you can get TB on an airplane," says Dr. Kenrad Nelson, director of epidemiology at the Johns Hopkins School of Public Health.
"The rise of multidrug-resistant tuberculosis is a public health catastrophe of the first order," says Dr. Paul Farmer, associate professor of medicine at the Harvard Medical School. "MDR-TB is a man-made problem. When patients stop taking or don't have enough of the right medications, they develop resistance to drugs and then spread the new drug-resistant strains of bacteria."
Nelson agrees, saying that poor and incomplete therapy has created the multidrug-resistant strain of TB, but immigration and global travel are doing their share to make MDR-TB a threat.
Diana G. Jordan, nursing program specialist in communicable disease at the Pinellas County Health Department, says that while the rise in MDR-TB is a significant problem, she doesn't think immigrants or refugees from eastern Europe are bringing it here. "People are screened for TB at the refugee camps," Jordan says. She is more concerned with the spread of globe-trotting illnesses and diseases that don't have to be reported by law, such as flu and chicken pox.
But what if a traveler coming into Tampa International Airport is thought by the airline crew or passengers to be ill with a communicable disease, such as TB?
Madeline Austin, who is the exposure control officer with the airport police, says that in 22 years she has never investigated a sick passenger. If there were suspicions about a traveler carrying TB, she said the concerns would be reported to the local public health facility. Most of her work, she says, is in protecting airport police after exposure to blood or body fluids. Occasional cases of chicken pox crop up, she admits, but it is usually revealed that the young travelers are under doctors' care and not contagious when they step into the airport.
"Any port of entry presents a risk for imported disease," says Dr. John Sinnott, professor of medicine at the University of South Florida School of Medicine. "We're in a new period of emerging infectious diseases. Day care, human sexual behavior, air travel, environment and growing cities are all contributing to the emergence of infectious diseases. Influenza loves to travel by airplane. All flu starts in the Far East, in pigs and ducks in China and spreads through airline travel."
The recent wave of flu has been no exception, Sinnott says, adding that influenza used to travel slowly, but it now moves at 600 miles per hour. Flu can be deadly. For example, he says, consider the 1918 world flu epidemic that traveled slowly to Europe during World War I on U.S. ships. That epidemic killed more people than did military action. Researchers think the 1918 flu was a double-whammy that started in ducks, then went to pigs, and a double strain attacked humans the world over. The same flu strain today could quickly circle the globe.
Is there any way to protect yourself from bugs as you travel? Nelson, who travels extensively in Asia studying HIV, the virus that causes AIDS, in Thailand, says Asians often wear surgical masks when they travel by air.
"I was on a recent long flight and seated next to someone coughing," Sinnott says. "I discreetly asked to have my seat changed. If you are traveling, get a flu shot and keep well hydrated."
As it turns out, the low humidity in airline cabins does not foster the spread of TB, which thrives in a warm, moist environment. The cabin environment in airplanes is ideal for catching flu bugs, however. They thrive in dry environments and low humidity where your mucus membranes dry out and make you more susceptible.
-- Randolph Fillmore is a freelance writer based in Tampa.