Common Insect Holds Key to Uncommon Disease

The bug could have caught a ride on an exotic bird bound for the Bronx. Or on planes carrying thousands of refugees from Kosovo, where the disease is as common as combat. Or maybe it’s been here for years, merely overlooked by communities that have increasingly stopped studying their local mosquitoes.

Wherever it came from, wherever it’s going, whatever it really is, the virus most frequently known as West Nile fever made its first recorded appearance in the Western Hemisphere on a very big stage: New York City. It has killed five people in the area, sickened at least 38 others and scared more people out of the forest than “The Blair Witch Project.”

Scientists aren’t sure if the disease, which has killed hundreds of birds in three states, will move south with migratory flocks for the winter and come back strong again next spring, or even whether it’s already run its course. But they do agree on one thing: West Nile fever wouldn’t be this week’s most heavily covered health threat if governments spent more time and money controlling the common mosquito, the world’s most menacing deliverer of deadly disease.

“When states are looking to cut budgets, these crazy entomologists out there looking for mosquitoes are an easy target,” said Durland Fish, an epidemiologist at Yale University. “You don’t wait for bodies to start piling up before you start controlling mosquitoes.”

A record summertime drought followed by massive flooding spawned by Hurricane Floyd--and now a tabloid-tantalizing plague with an exotic name--have left parts of the Northeast feeling beset by bad luck of biblical proportions. While the epicenter, New York City, isn’t exactly emptying out, people here and in surrounding counties and states are drenching themselves with repellent, keeping the kids out of parks and indoors after dark, and flooding local health departments with demands for autopsies on dead birds on their doorsteps.

Crews from the U.S. Centers for Disease Control and Prevention are collecting voluntary blood samples from residents of 300 households in the borough of Queens, where the disease was first identified in humans, to see just how prevalent it is. Other experts are checking dead migratory birds down to Florida to find out if the disease has moved south. Even Brazil has begun spraying pesticide on airplanes arriving from New York.

Other scientists are checking to see whether the virus is carried by pigeons and ticks and infecting livestock, while others are wondering whether the disease is really West Nile--which has been found mainly in Africa and parts of Europe, with recent epidemics reported in Russia and Czechoslovakia--or an Asian cousin called Kunjin, or some mutant strain of either.

The fact that it’s an alien virus with an exotic name infecting humans via a common insect and ordinary birds has given the disease an especially creepy cachet in a city more in harmony with roaches and rats.

The state opened a toll-free information hotline Tuesday and it crashed within hours because of anxiety overload. Of the thousands of callers, the biggest number were concerned with the pesticide spraying, though folks worried about viral symptoms were a close second.

“We’ve heard some outrageous statements,” said Kristine Smith, New York State Public Health Department spokeswoman. “We have people wondering if they should go to the emergency room with a mosquito bite.”

Joanna Burger, because she’s a Rutgers University ornithologist, has had about 30 dead and decidedly unsolicited birds brought to her door. “Of course people are panicking,” she said, speaking on the condition that it be made clear she wants no more dead birds.

In Westchester County, which includes some of the wealthiest communities in metropolitan New York, more than 14,000 people have jammed the county’s hotline in the last week, according to the health department. The disease has infected eight people and killed one in the county.

Like a lot of communities, Westchester had an ongoing mosquito abatement program until the mid-1980s, when cuts in state and federal revenue sharing led to cuts in monitoring and spraying programs that seemed disposable once their effectiveness was taken for granted.

New York City stopped active surveillance and spraying in the early 1980s, though it will occasionally do some spot spraying, said city health spokeswoman Sandra Mullin. The city budgets only $120,000 a year for what is termed vector control, though Mullin said some occasional mosquito-squelching efforts have come from the $14-million pest control budget.

That will change. “We’re going to make it a very big priority from here on in,” Mullin said.

West Nile can cause fever, headache or other flu-like symptoms in most people, and in rare cases can kill the very old, very young, or people with weakened immune systems.

West Nile encephalitis is actually a milder Old World version of the indigenous St. Louis encephalitis and, like other mosquito-borne diseases, would not be killing people if states and local governments realized the mosquito’s potential for harm, said Rutgers entomologist Wayne Crans.

Dead birds, particularly crows, are piling up across New Jersey, but no human in the state has been diagnosed with the West Nile-like disease, Crans said. Unlike New York, the state requires every county to have a mosquito control commission.

“As a result, New Jersey residents have been spared,” he said. “In the places where people are dropping, now, suddenly, they’re developing mosquito-control programs.”

New Jersey adopted its programs in 1914, largely to control malaria, the mosquito-borne disease that still kills more people globally than any other. Last month, a couple of boys caught malaria during a Boy Scout outing on New York’s Long Island, a reminder that seemingly eradicated diseases are capable of making a comeback if the carrier insect goes unchecked.

In New Jersey, standing water is typically treated with bacteria that kill only mosquito larvae, reducing the need for the sort of massive, discomfiting aerial pesticide spraying that New York carried out in recent weeks.

“People are seeing helicopters in the air spraying and they say, ‘That’s mosquito control,’ ” Crans said. “That’s crisis management. Mosquito control starts with eliminating habitats.”

The combination of drought and then the rain created ideal breeding conditions for a sudden burst of mosquitoes, experts say. Much of the talk of the town has been just where the disease originated. It was originally identified as St. Louis encephalitis last month when birds began dying at the Bronx Zoo. Then it was identified as West Nile. Now, scientists are calling it a “West Nile-like” virus.

If it came from abroad (nobody has ruled out that the disease is indigenous), a virus-carrying mosquito could have hitched a ride on a cruise ship, airplane or piece of luggage or the virus itself could have come aboard an imported bird.

World Health Organization country profiles note that West Nile has existed in the former Yugoslavia. The United States this year staged a frenzied campaign to take in Kosovo refugees during the brutal ethnic cleansing launched by Serbia. Most landed in New York or New Jersey, and U.S. troops and aid workers have shuttled back and forth to the war-torn Balkans for several years.

Population upheavals are key factors in the spread of disease, and the fall of Communism and opening of borders this decade have led to one of the biggest global migrations ever. More than 100 million people have sought asylum in other countries since 1989.

Dr. Heather Papowitz, an internal medicine specialists who worked for the relief group Doctors of the World in Macedonia, said that 1991 medical literature indicated that West Nile affected 5% of a sample population that included Kosovo, and that the risk was considered greatest in spring and summer, when the largest refugee exodus took place.

With deadlier and more contagious diseases such as tuberculosis a greater concern, West Nile fever probably wouldn’t have been even noticed, she said. “It was pure chaos out there,” she said.

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How Mosquito-Borne Virus Persists

The West Nile strain of encephalitis (originally classified as the St. Louis strain) has killed five people and sickened dozens in the Northeast and could potentially spread south to other regions as infected birds begin their fall migrations.

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Source: AP, Centers for Disease Control and Prevention, “The Nature of North America”