County Puts The Bite On West Nile
Health officers have given 13 Power Point presentations so far to 415 people including one manager of a local golf course, and 25 more such gatherings are scheduled for this month.
The county’s “Train the Trainer” program has trained 22 people so far, creating sort of a speakers bureau, whose members can provide disease prevention measures to anyone wanting to learn how to manage the virus.
Two other elements of the plan, surveillance and mosquito control, are underway, too.
The reporting and mapping of dead crows — a few have already been spotted — is being done through the department’s Web site at www.accesskent.com/westnile.
The department is also offering information on how to control the mosquito population and has negotiated a bulk rate on the price of larvacide. Residents can get details and place an order by calling 336-3030.
The plan emerged from a February meeting that the department held with health officials and environmental specialists from a dozen public health departments in West Michigan.
“The plan came about from looking at the most current information we had about West Nile.
“What we knew about it had a basis in science and we made our recommendations based on the current state of the science,” said Cathy Raevsky, administrative health officer for Kent County.
“We recognized that we had to be flexible, as the science changes — as it sometimes will,” she added.
The science changes because West Nile is a fairly new disease, first detected in 1999. The virus had its biggest outbreak in 2002, infecting thousands of residents in 41 states.
West Nile is largely considered to be an urban disease because the primary carrier, the Culex pipiens mosquito, prefers cities to rural areas. The Culex has a flight range of a mile, but seldom strays more than a few hundred feet from its breeding site — usually a standing pool of dirty water — and it breeds every three weeks.
More than two-thirds of those infected in the county last year lived in a city.
“A big part of our program is surveillance. We know it is an urban disease,” said Mary Swanson, assistant county administrator. “We are spending our dollars on educating people on how to protect themselves.”
Raevsky told the Business Journal the county considered adding a program to the plan that would have sprayed the adult Culex, but chose not to do that.
Their concern was that doing so might result in more harm than good, especially for residents who might be allergic to the chemicals in the spray and for those who have upper respiratory problems. The spraying could have also killed insects that are beneficial for the environment.
Instead, the county decided to attack only the offspring.
“You can’t just kill the adults and expect to have any huge impact. But killing the larvae does stop the next generation,” said Raevsky.
“They like to breed in, basically, small pools of very nasty, dirty water. That’s why they tend to be in tires in the backyard, in birdbaths, because the water just stands there. And that is why our educational programs emphasize the personal protection aspects,” she said
Raevsky added education is the most cost-effective measure of the plan. Getting residents to dump pools of standing water, or remove items that can hold water from their properties is a bargain anytime — but even more so when public budgets are tight.
The 2003 health department budget is $27.3 million, a figure up by 3 percent from last year but almost $600,000 less than health officials requested.
Raevsky said a few agencies within the department are footing the bill for the West Nile campaign, as a specific budget wasn’t created for the plan.
With money not being a major issue, perhaps the toughest West Nile nut that the department may have to crack could come next fall when health officials will have to determine whether their plan succeeded.
“That is extremely difficult to say because there are a lot of unknowns,” said Raevsky.
“If we have a lot more cases here that doesn’t mean that what we did was a failure. That may mean what we did had a lot of impact and we actually prevented what may have been a much, much worse season.”
The weather this summer and the size of the mosquito population are just two of the unpredictable variables the county will face in making that determination.
If it rains regularly and the resulting rainwater washes out stagnant pools of standing water, there could be fewer mosquitoes in the county. If it is hot, humid and dry like last summer, dawn and dusk will again be mealtimes for mosquitoes.
Another unknown is exactly how many crows mosquitoes killed last year. Some evidence shows the county doesn’t have as many crows this year as it had last year, when 57 cases and four deaths were reported. Fewer crows could mean less human suffering.
But the most mysterious factor of all for the county are the people who were infected last year, but didn’t become ill. Raevsky said the county doesn’t know how many were bitten, but had their immune systems negate the effect of the bite. That aspect alone could leave the county with a false-positive result for the plan.
“You could have a horrible year for mosquitoes, a horrible year for West Nile, but if everybody is already immune, you’re not going to have any human disease,” she said.
“It’s extremely complicated,” she stressed.
“There are probably variables that we may not know anything about that may impact on this, too.”