Mosquito Virus Exposes a Hole in the Safety Net
By ANDREW C. REVKIN
Published: October 4, 1999
It may have come in the blood of a traveler returning from Africa or Europe. It may have hitchhiked in an infected bird smuggled in baggage. There is even a slight chance that it came in the gut of a mosquito that flitted into a jet.
But as medical sleuths try to trace the path of the West Nile-like virus that has helicopters fumigating New York City and its suburbs, they are also confronting a much larger problem.
This virus, which has killed four people and scores of birds, is just one of dozens of hazards to people, crops, livestock, and wildlife that -- after being hemmed in by oceans for millenniums -- are increasingly free to hopscotch the world because of the acceleration and growth of international travel and trade.
The threat is greatest in the country's biggest hubs of global commerce: New York City, Los Angeles and Miami.
''We've gotten over being surprised,'' said Dr. James Hughes, the director of the National Center for Infectious Diseases at the Federal Centers for Disease Control and Prevention, which is promoting a new plan to improve surveillance and responses when an outbreak occurs. ''We're making some progress, and it's a good thing,'' Dr. Hughes said, ''because the microbes are certainly out there.''
Medical and agricultural inspectors and experts are working around the clock to spot new threats. But the West Nile-like virus proves that the safety net is, at best, incomplete.
Some of the enemies are invisible microbes; others are as conspicuous as the freight-hopping, tree-drilling, two-inch Asian long-horned beetle, a threat to hardwood forests. The beetle made its North American debut in Greenpoint, Brooklyn, in 1996 and has since appeared in Chicago and, most recently, on the Upper West Side of Manhattan, just blocks from the greenery of Central Park. The beetle probably arrived in the 1980's in wooden shipping pallets, said Henry J. Stern, the City Commissioner of Parks and Recreation.
Mr. Stern said the beetle and now the virus show that nature is still capable of throwing surprises at the world's dominant species.
''In the modern age, this mechanical age, we think we've conquered the planet,'' he said. ''But we're not quite the masters of the universe we think we are.''
Improvements in transportation have always been followed by movements of harmful species, said William H. McNeill, the author of the book ''Plagues and Peoples,'' which he updated last year. Smallpox accompanied seagoing European settlers to the Americas. But potato blight did not move from the Americas to Europe until the mid-1800's, when the advent of swifter ships allowed potatoes to arrive fresh, with the harmful mold healthy and alive.
At the end of the 20th century, the explosive growth in airplane traffic has amplified the problem. The number of international passenger and cargo flights to and from airports serving New York City doubled just from 1987 to 1997, to 187,785 from 93,008, according to the Port Authority of New York and New Jersey.
The flow of goods and travelers can only be spot-checked by inspectors seeking threats. Screening for imported diseases is nearly impossible because West Nile and many other dangerous ailments often are carried without symptoms for days or weeks.
The effort to monitor and sequester sick passengers has shrunk substantially in recent decades; the number of Federal quarantine stations at airports dropped from 55 in 1967 to 8 today, Federal health officials said. One of the eight is at Kennedy International Airport.
The only really effective way to track imported infections is to communicate well with hospitals and doctors, local health officials said.
''Having one inspector for every person coming in would not prevent disease from coming in,'' said Dr. Marcelle C. Layton, the assistant commissioner for communicable diseases of the New York City Health Department. So when some new threat is identified, the only recourse is often to wait for cases to start popping up at city hospitals, city health officials say.
A swift response is then essential, she said, explaining that New York City, with 24,000 people per square mile, is twice as crowded as the country's second most densely populated city, Chicago.
In a parallel effort, teams of inspectors are also on the lookout for agricultural pests or diseases. Some of the dogs sniffing bags at airport terminals are looking not for drugs or bombs, but for oranges that might carry imported fruit flies; for giant African snails that are a delicacy to some, but to agriculture officials are a potential scourge, and for sausage, which has been occasionally found sewn into coat linings of epicures, and which can harbor mad cow disease or hog cholera.
Occasionally, officials are amazed by what they find. Beagles at Kennedy recently sniffed out a partly stuffed cow head arriving from Argentina. Just last week, someone brought two bucketloads of live Vietnamese apple snails, which are voracious rice pests, into Los Angeles International Airport, said Joseph Cavey, a biologist with the Animal and Plant Health Inspection Service, a branch of the Federal Agriculture Department that monitors imported hazards.
''There was a woman once who was hiding her pet parrot under her dress,'' Mr. Cavey said. ''You could see it moving.''