Friday, May 30, 2003 at 1:48 PM
West Nile Virus season is just around the corner and many Northeast Ohio health districts are grappling with the big question - to spray or not to spray? Last year's outbreak hit Ohio hard. Public health officials in many communities decided to spray pesticides on adult mosquitoes, hoping to reduce the chance of infection in humans. But spraying was met by a public outcry from some residents concerned about the immediate and possible long-term health effects of the chemicals. This year, some health departments have chosen to focus their control efforts on killing mosquito larva before they hatch with chemicals that are relatively benign. Others still plan to incorporate spraying into their total pest management strategy. ideastream's Karen Schaefer reports on the thinking behind the different responses to this summer's West Nile Virus threat.
Last year, West Nile Virus hit Ohio hard - harder than any public health official had expected. In Cuyahoga County alone, 211 human cases were confirmed and 14 people died. The County’s health district - the largest in the region - decided to do a sero-survey, taking blood samples from about 1,200 residents to find out just how many people actually got West Nile Virus without noticing any symptoms. Assistant Administrator Terry Allen says the results were surprising.
Terry Allen: We found that between 4 and about 6 1/2% of residents were exposed to WNV. That equates to perhaps 50-80,000 people in Cuyahoga County that were exposed last year.
Allen admits that one way of looking at those figures is to see that the number of deaths in the infected population was extremely low. But Allen views the numbers differently.
Terry Allen: We search for something called herd immunity, that is, if you think of a herd of animals, that if a large number of animals are exposed that are in the herd, that it would reduce the potential for an outbreak to occur. We know that, for certain diseases, if you were to inoculate a certain percentage of the population - 80% for instance - you’re not likely to see an outbreak of disease. So in our case, with 50-80,000 people exposed… with 1.4 million people in the county, we have a long way to go to reach that.
Allen is concerned that a new outbreak of West Nile could infect thousands of people who weren’t exposed last year and could cause even more deaths. So he says the county has decided to take all possible precautions - including spraying a pesticide on adult mosquitoes in areas where human cases are reported.
Barry Zucker: You have to put this in context. Most counties in Ohio do not spray for mosquito control.
That’s Barry Zucker, president of the Ohio Coalition Against the Misuse of Pesticides. He’s one of many county residents who oppose spraying.
Barry Zucker: What the doctors tell us and what the medical studies tell us is that there are real and potential health consequences from pesticides - everything from upper respiratory diseases to possible neurological damage to possible increase in breast cancer. The bottom line is that pesticide spraying for adult mosquitoes does not work.
Bill Tomko: Our concerns relative to the county board of health was they didn’t really have any data that indicated that the spraying would do any good. And we became quite concerned that it was being done to have the appearance of action in order to quell the emotional response of, well, you know, do something, protect me, as opposed to really address the underlying cause.
Bill Tomko is president of the village council of Chagrin Falls. His community is one of many in the region that have decided not to spray.
Bill Tomko: My first reaction is just to extrapolate from the medical profession when you’re looking at spraying versus not spraying, first do no harm. The better way to do it is to apply individual protection measures and to go after the breeding of the mosquitoes themselves, which is what we adopted to do in Chagrin Falls by adopting a larvicide program.
Tomko says his community will pepper catch basins and areas of standing water with a chemical briquette that kills only mosquito larva. Combined with a reduction of breeding sites, continued surveillance, and a public information campaign about the need for personal protection, Tomko hopes to keep residents safe from infection. Last year, no one in Chagrin Falls got sick. But Cuyahoga County Health Director Tim Horgan says, with the high infection rate seen last year in urban areas, he just can’t take that risk. So in addition to larvicide, surveillance, and all the rest, Horgan says the county will use pesticide sprays if conditions warrant. He warns that even residents on the county’s no-spray list could see pesticide spraying in their neighborhoods this summer.
Tim Horgan: We might have areas where’s there’s a number of houses on an individual street where people would rather not be sprayed. And then we might have a case or two of human disease right in that area. If that happens to us this year, we’re going to notify people on the list, let them know we’re going to be there. But I think we’re going to try to go in and make sure that area gets sprayed and that’s very consistent with the recommendations of the CDC.
But even the head of the Centers for Disease Control admits there’s not enough good scientific evidence to be sure spraying works. So while some health districts like Cuyahoga County and the city of Cleveland plan to spray, others - like Chagrin Falls, Shaker Heights and Oberlin - do not. What all health officials do agree on is that taking personal responsibility for protection against mosquito bites is essential for keeping West Nile at bay. In Cleveland, Karen Schaefer, 90.3.
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