ANNAPOLIS – The state Department of Agriculture is caught between two demanding groups on the West Nile virus issue: the worried public and protective environmentalists.
With two human cases of the virus announced in Maryland last week, the first ones in the state, the public demand for mosquito spraying is high. At the same time, the chemical used on West Nile carrier mosquitoes can threaten wildlife in the Chesapeake Bay, environmentalists say.
The department says it’s struck a balance between the two groups that is working to protect the public health and coastal wildlife.
Department of Agriculture officials will increase mosquito spraying in the coming weeks to try to prevent the spread of West Nile to another human victim.
A 72-year-old Baltimore man is in serious but stable condition at Sinai hospital and health officials said Thursday they are 98 percent sure the man has the West Nile virus.
On Friday, state health officials disclosed that a 63-year-old woman from the Eastpoint area of Baltimore County also had tested positive for the virus after being sick since late August. Her condition, they said, is improving.
Until this week, the agriculture department did not often spray specifically to eliminate mosquitoes carrying the West Nile virus, said Don Vandrey, department spokesman. The state frequently does spray at the request of communities to kill large mosquito populations.
What concerns scientists and citizens is the government is not assessing the risk of spraying the pesticide compared to the risk of people contracting the virus.
There’s a strong risk of doing more harm than good by spraying more than is necessary for a virus that affects so few in the population, said Kim Coble, a Chesapeake Bay Foundation scientist.
“The potential risks from pesticides is just too great,” she said.
Reading the label alone of the pesticide permethrin, the chemical of choice to eradicate mosquitoes, is enough to cause concern about the methods used to spray it. “This product is extremely toxic to fish and other aquatic organisms,” the label says. “Do not apply directly to water or to areas where surface water is present or to intertidal areas below the mean high water mark.” While the department says it avoids spraying near water, Coble said no one is really monitoring applications. Plus, she said, the effects of the spraying are unknown. “The impact of that kind of thing is really not tracked,” Coble said. But the bottom line, said Coble, is whether the spraying is effective. She said it’s not because mosquitoes literally have to fly right into the spray to be killed.
However, Vandrey said spraying has proven effective.
“We know we are getting much lower mosquito counts,” he said.
He also said spraying in Baltimore has been done on Federal Hill, which is near the waters of the bay. Effective or not, the reason the department sprays for West Nile virus is that the public demands it. Next year, however, Vandrey said there likely will be less spraying for mosquitoes.
“Each year, the level of anxiety and interest drops dramatically. The public concern for West Nile Virus is actually greater than the threat,” he said.
The most effective way to control mosquito populations is to get rid of standing water said Lynn Goldman, professor at Johns Hopkins University, who added that the public needs to be more aware of such control measures.
In addition, there are safer pesticides that can be used, she said, but they are more expensive.
George Gee, part of the crane restoration ecology team at the Patuxent Wildlife Refuge, said he is not concerned about the effect of the pesticide on birds or other wildlife.
“It’s one of the least problematic ones out there,” he said. “A lot more herbicides that we use on our lawns are probably more dangerous than that.” — 30 – CNS-9-7-01