Subject: Doubts About Spraying---- To: Paul Helliker <phelliker@cdpr.ca.gov> Dear Mr. Helliker, I thought you might like to read an article that appeared today in NEWSDAY, 11/7/2000, entitled: Doubts About Spraying - Some experts call it ineffective against West Nile virus - by  DAN FAGIN - Staff Writer. On the ground and in the air, the war on West Nile virus is over in New York for this year. But some experts and activists are increasingly wondering whether one of the chief weapons, insecticide spraying, has made much of a difference in controlling the spread of the mosquito-borne virus. There have been just 13 confirmed West Nile-related illnesses this year in New York State, down from 69 last year. But the virus that was first confirmed in the United States just more than a year ago in Queens continues to spread geographically and has now killed birds in 11 northeastern states. Spraying has stopped for the year because the cooler weather has reduced mosquito activity. While scientists from the federal Centers for Disease Control and Prevention and other agencies are tracking the virus and have launched an all-out effort to understand how it spreads, virtually no research is under way on the effectiveness of spraying. Insecticide application, especially from the air, has been the most controversial aspect of the West Nile effort, spurring numerous lawsuits and protests around the region. In fact, 14 months after local governments throughout metropolitan New York began deploying spray trucks and helicopters to fight West Nile, health officials at all levels of government still have released only rough estimates, not specific data, about how effective spraying has been in killing disease-carrying mosquitoes. "We need to address this, because if we're just spraying all over and not doing a damn bit of good, then this is a waste of time and money, and it's also a hazard, said David Pimentel, a professor of entomology at Cornell University and a longtime pesticide researcher. Up to now, the debate over spraying has mostly centered on the health risks of products such as Anvil, Scourge and malathion. According to the U.S. Environmental Protection Agency, all three pose acceptably low health risks to people when sprayed at the very low dosages specified on the label. Increasingly, however, critics and some researchers are suggesting it's just as important to look at whether the sprays are an effective way of controlling West Nile. That's especially important, they argue, as evidence accumulates that the virus only rarely causes severe illness in the people it infects, and it can be transmitted by seven or more mosquito species, each with different breeding, flying and biting habits. Last week, researchers at the federal National Wildlife Health Center in Wisconsin added to the confusion over how best to control West Nile by confirming that mosquitoes are not the sole vector for the virus, which can also pass from bird to bird. "There's not enough evidence that all this spraying has changed the dynamic of the outbreak, and that's in part because the studies really haven't been done to find out, said Michael Hansen, the chief pesticide researcher at Consumers Union, which publishes Consumer Reports magazine. The architects of the campaign to control West Nile acknowledge the lack of scientific evidence. Getting it, they say, is a daunting challenge that is necessarily less urgent than understanding the details of how the potentially lethal virus is transmitted. In the absence of stronger evidence, advocates of spraying argue that the relatively low rate of severe human illness this year -- there have been no deaths in New York State in 2000 from West Nile, and just seven last year -- demonstrates that insecticides, along with public education and efforts to eliminate mosquito breeding sites, is keeping most people safe even as the virus spreads geographically. "We've always said there's no way we could break the transmission cycle in nature and stop this virus from spreading without doing a lot more spraying than would be acceptable to the public, said Dr. Stephen Ostroff, a senior CDC official who is coordinating a nationwide effort to control the virus. "So our perspective on the use of pesticides is that we're trying to reduce the risk of illness to humans, and there's no question that we've succeeded. "One could argue that the number of human cases would have been low anyway, even without spraying. We'll never know the answer to that, and I don't necessarily want to know, because I'm not going to recommend that local communities put people at risk by not using all of the appropriate control measures. Critics and supporters of insecticide spraying agree on
one thing: It's not the most efficient way to control mosquitoes. Studies have consistently shown that, on average, less than
one-tenth of 1 percent of the millions of droplets released from a helicopter or
plane during a typical spraying run actually hits a mosquito, according to
Cornell's Pimentel, who believes spraying is nonetheless justifiable in some
circumstances. In addition, he
said, if there are numerous trees, buildings or other obstructions in the area,
the spray cloud will almost certainly miss large areas of the target zone,
including mosquitoes inside buildings. For those reasons and others, the consensus among experts
is that educating the public about how to avoid being bitten, eliminating
breeding sites and killing larval mosquitoes with less-toxic sprays before they
take wing are all more efficient than trying to kill adult mosquitoes with
pesticides. But health officials in
New York City, Nassau, Suffolk and other local governments around the region
said even though they emphasized preventative measures this spring, by
midsummer, their surveillance efforts were showing that many mosquitoes and
birds around the region were infected, often in densely populated areas. At that
point, they said, spraying was the best control option left. The debate over whether they made the right choice is especially complicated because it's so difficult to measure or even define a successful pesticide application. "It's just not a straightforward thing to measure the efficacy of a large spray, because weather and other conditions can vary so much from place to place and from hour to hour, said Dominick Ninivaggi, who heads the mosquito-control program in Suffolk County, the most extensive in New York State. Local health officials say they have undertaken some small-scale experiments by trapping and counting mosquitoes before and after an area is sprayed. They haven't released their data because, they say, they're still analyzing it. "We agree that effectiveness is an important question, and we intend to answer it, said Dr. James Miller, West Nile coordinator for the New York City Health Department. Suffolk also says its data isn't ready for public disclosure, and Nassau officials did not return phone calls. Though they haven't released any data, Miller and other New York City officials estimate that in the city, mosquito counts after a spraying are "up to 85 percent lower than they were beforehand. And Deputy Commissioner Carl Johnson of the state Department of Environmental Conservation, which regulates pesticide use around the state, said local governments have anecdotally reported "60 to 80 percent reductions after spraying. Some mosquito-control experts from outside the region, however, are skeptical. "I find it hard to think that they could consistently get 85 percent control spraying in an environment with so many trees and houses and other obstructions. But I'd really have to look at the data to know for sure, said Judy Hansen, a past president of the American Mosquito Control Association who has run the mosquito-control program in Cape May County, N.J., for 40 years. "The people in New York ought to be very cautious about saying they're getting 85 percent control, agreed Ray Parsons, who runs Houston's program and was a consultant to Rockland County this year. Trap experiments in residential areas in Florida, the state with the most extensive mosquito-control experience, generally show a reduction of about 30 percent after a spraying, "and that's also about what we get in Houston, Parsons said. Figuring out whether spraying is keeping people from getting sick is even more difficult than determining how well it's killing mosquitoes. The CDC is in the midst of an extensive West Nile study
aimed at measuring human infection rates in portions of Staten Island, Babylon
and Stamford, Conn. But the agency isn't even attempting the daunting
statistical task of looking for a link between the infection rate in each
community and the amount of insecticides sprayed there.
"The simpler questions about infection rates need to be answered
first, said the study's director, Dr. Anthony Marfin of the CDC. Several years ago, Pimentel reviewed spraying records in Memphis, Dallas and several other southern cities to see if the number of St. Louis encephalitis cases declined significantly after spraying. Pimentel said he concluded that the question couldn't be answered scientifically because there weren't enough diagnosed cases to be statistically meaningful. West Nile, he said, triggers severe illness even more rarely than the St. Louis virus, so it will be even more difficult to design a meaningful study to gauge the effectiveness of spraying. Another dilemma is that one of the most scientifically
sound way of studying the problem -- by comparing two nearly identical
communities with high infection rates -- would require leaving one of those
communities unsprayed despite evidence that people who live there are infected
with the virus. "That's just
not going to happen, said Johnson of the state DEC. "It's a risk no one in
public health would ever take. Well Mr. Helliker, it simply amazes me that those in
"public health" continually ignore all of the known and unknown
risks associated with your "registered" POISONS!
If your "registered" POISONS actually were "85%
effective" in "controlling" pest problems, why do we still have
any "pests" left to bite us, after all of the repeated POISON
sprayings? What bothers me most of
all is even if you could kill every single mosquito, the research from Beloit,
Wisconsin clearly proves you STILL will have West Nile Virus!
Will you then kill all of the birds? |
