Nashua (N.H.) Telegraph
August 12, 2005

With summer comes threat of mosquito-borne viruses

QUOTABLE: "At the heart of this debate, moreover, is a concept
scientists refer to as 'the precautionary principle,' an ethic of
public health that weighs risks and benefits in the context of high

By Hattie Bernstein

Death by mosquito bite sounds like the title of a vacation thriller.

It's not.

Since the summer of 1999 when the West Nile virus made its first
appearance in North America, state public health officials have been
urging vigilance, debating and undertaking pesticide spraying programs,
and recommending a number of other preventive measures to reduce or
eliminate the risk of being bitten.

But are these measures necessary considering that nobody in New
Hampshire has ever died from West Nile virus?

"The risk is very small, but not getting bitten, the risk is even
smaller," said Dr. Alex Granok, an infectious disease specialist
affiliated with Southern New Hampshire Medical Center and St. Joseph
Hospital. "A simple precaution can eliminate the risk."

Likewise, these precautions protect against eastern equine
encephalitis, another disease carried by mosquitoes that was reported
in New Hampshire late last week after three birds tested positive for
it in Concord and Manchester. EEE, state officials said, can cause more
serious illness than West Nile virus.

But the odds, which are weighted by age and immune status, favor most
state residents.

"In an area with a lot of West Nile virus, there's a 6 percent
infection rate in mosquitoes," Granok said. "In an area where it's
highly prevalent - and New Hampshire is not - 94 percent of mosquitoes
won't have it."

State officials said 35 percent of those bitten by a mosquito carrying
EEE will become ill and die.

But while the experts agree that an ounce of prevention is worth the
proverbial pound of cure, they also differ over some critical aspects
of prevention. At the heart of this debate, moreover, is a concept
scientists refer to as "the precautionary principle," an ethic of
public health that weighs risks and benefits in the context of high

While West Nile virus is rare, it can be deadly. On the other hand,
precautions such as spraying with pesticides may reduce the mosquito
population but produce longer-term results effecting humans, animals
and the environment that are serious or irreversible.

This principle, based on consideration of tradeoffs between uncertain
risks, is a difficult one to grasp given the pressure on government
officials to act quickly in the face of a public health threat. It is
also difficult to communicate to a public hungry for answers.

What most people want is a simple answer to a complicated question:
Will the mosquito that bites me kill me?

Granok said 80 percent of those bitten by an infected mosquito will
have no symptoms, although about 1 percent of those infected will
develop serious central nervous system disorders and about 10 percent
of those will die. Furthermore, the risk is weighted toward those who
are 65 or older.

Others agree, saying a few small changes in behavior - emptying
birdbaths in the yard, repairing screens, using a pesticide repellant
during outdoor activities, and wearing long-sleeves and long pants -
significantly reduce the risk of infection and death.

"In general, the risk is pretty low. But that said, it makes all the
sense in the world to take normal precautions," said Joel Tickner,
research assistant professor in the Department of Work Environment at
the University of Massachusetts Lowell. "Should you go to the extent of
not going outside? Absolutely not. But it's not so little that you
wouldn't take reasonable precautions."

That's also the thinking of Nashua public health officials, who since
June have been collecting mosquitoes and sending them to the state
health department lab for analysis. Heidi Peek, deputy health officer
for the city's environmental health department, said her office had
collected 432 mosquitoes as of Aug. 4 and none tested positive for West

"Generally, West Nile, EEE is unusual in people," said epidemiologist
Paul Etkind, deputy director of the Nashua division of public health
and community services. "We pay attention because it can be a fairly
severe illness - small numbers but severe consequences."

Etkind's position reflects that of state epidemiologist Dr. Jose
Montero, who late last week announced his department had confirmed the
presence of West Nile virus in a bird found in Pembroke. Montero also
noted that three birds in the Concord and Manchester areas had tested
positive for eastern equine encephalitis.

As of late last week, state officials reported that 13 birds and 747
mosquito pools had been sent to the state lab for testing. There have
been no positive mosquito pools, horses or human cases of the diseases
in the state so far this year, according to officials.

But while the odds of getting either West Nile or EEE are low, many,
particularly those engaged in outdoor activities like hiking, camping
and kayaking, are taking heed.

"They're making decisions to go with a little more potent bug
repellant," said Kat Conley, manager of Eastern Mountain Sports in
Nashua. "They're judging whether to go with a little more and not be as
susceptible or go natural and be more susceptible. I see people
weighing that decision daily."

Conley has done the same.

Before heading outdoors, she sprays her clothing and gear with a
pesticide made expressly for this purpose. She also rubs a small amount
of another type of repellant on her face and covers her head with a

"I prefer treating clothing and gear, not putting (repellant) on my
skin," she said, adding that she tells customers who prefer the skin
sprays to apply them after rubbing in their sunscreen and to reapply
after sweating profusely or spending time in water.

Copyright 2003, Telegraph Publishing Company, Nashua, New Hampshire