Digital Extra

5.18.2000
State gearing up to combat arrival of West Nile virus
By PETER B. LORD
Journal Environment Writer

PROVIDENCE -- If the water is flowing, it probably won't produce mosquitoes. If it's a puddle that dries up in less than a week, or a pond that's always got water, there probably won't be any mosquitoes either.

It's those ditches and drainage basins that are wet longer than a week, but not all the time, that the state is targeting in its war on mosquitoes and the West Nile virus they might bring to Rhode Island.

The state Department of Environmental Management yesterday finished distributing boxes of larvicides to workers from each of the state's cities and towns. DEM directed them to begin spreading the larvicides early next month -- no earlier than June 1 -- in an effort to kill the mosquitoes before they take flight.

Also this week , the DEM hired someone to collect certain dead birds that appear in Rhode Island to determine if they've been stricken with West Nile. Each bird's brain will be removed at the state Health Department and the brains will be analyzed at a new laboratory at the University of Rhode Island.

Starting next week, the DEM will set traps to collect mosquitoes so they can be analyzed for signs of West Nile.

And soon, the Health Department will launch an advertising campaign to help make the public aware of West Nile and advise people what they can do about it.

It's all part of a $250,000 program that the DEM and the Health Department began organizing last November, soon after the fall frost put an end to a West Nile panic in New York City.

The disease -- a form of encephalitis or brain inflammation -- is common in Africa and Eastern Europe but had never been seen in the United States until it showed up last fall in New York. When it was over, 62 people were stricken and 7 died. Thirteen horses on Long Island were killed, along with many birds, and New York spent $20 million on pesticides.

West Nile also was found in mosquitoes captured in Connecticut and New Jersey.

This year, officials fear the disease will come back to the region with migrating birds. They suspect that if it does come back, it will take some months to build up in the mosquito population to a point where it becomes a threat to humans.

"It's a virus that multiplies in birds and mosquitoes. And it takes time to build up," said Alan D. Gettman, the state's mosquito-abatement coordinator. "So we're predicting it will be a late-season disease, if it occurs at all. But we don't know that for sure."

All of the New York illnesses were caused by a common house mosquito called Culex pipiens that health officials believe bred in the stagnant water of the city's storm drains.

Already, New York City has treated all of its 130,000 storm drains with bricks that will continually release larvicides for 150 days -- most of the summer breeding period.

Because of the New York scenario, Rhode Island also is targeting catch basins.

"It was determined in New York, particularly in drought conditions where water would stagnate, that catch basins were a particularly dangerous source of breeding," said Malcolm Grant, associate director at the DEM. "So our plan is to keep the population of that mosquito from getting to meaningful levels."

Communities were asked to estimate the number of catch basins they had, and the DEM distributed cases of a larvicide, Altosid, based on those numbers.

Providence figured it has more than 12,000 catch basins so it got nearly 300 pounds of larvicides. Foster figured it had only 11 catch basins, so the DEM didn't even bother breaking open one of its 44-pound containers for that town.

Each catch basin will get a dose of about half a teaspoon of larvicide that will be released over a 30-day period.

State officials acknowledged that a second kind of mosquito, Aedes vexans, was found with West Nile in New Jersey and Connecticut. While the Culex likes urban areas and murky water, the Aedes breeds in suburban and rural areas.

So the DEM also distributed a bacteria-based larvicide that can be dropped into ponds or drainage ditches. State officials acknowledged their efforts in rural areas will be far from comprehensive.

"We realize there are acres and acres of wetlands in the boonies that won't get treated, but that's a practical matter," Grant said. "Zero tolerance is not possible. We are trying to attack them where the most people are."

The bacteria-based larvicides are available to the public in stores, so people who own large tracts with drainage ditches and other wet spots can treat their own properties.

Rhode Island is not alone in this effort. Every state from Texas to Maine has organized new or upgraded mosquito-abatement programs.

Connecticut, for instance, is giving about $500,000 to communities to buy larvicides, according to David Leff, deputy commissioner of Connecticut's Department of Environmental Protection. That's about 10 times the amount being spent on larvicides in Rhode Island.

Most of the states also have launched public education campaigns urging residents to clean up places where mosquitoes may breed, and to avoid mosquitoes during the hours they are out.

The Rhode Island Health Department has created a comprehensive Web site that includes facts about West Nile, a map of its occurrences last year, details of Rhode Island's plans for attacking the disease this year and suggestions on what citizens can do.

The site also has links to similar Web sites in other states, as well as the Centers for Disease Control and Prevention, which is tracking the disease on a regional basis.

The Web site is at http:www.health.state.ri.us/wnv/wnvhome.htm.

"There's no need for anxiety here. People need not be frightened," Gettman said. "We're wanting people to be aware of this. But it hasn't shown up yet. It may not show up at all. And we're doing what we can do to reduce the mosquito population."