A few Mid-Michigan residents have complained to me that they
don’t know what to make of the reports in the news about West Nile Virus. They tell me they are hearing that it is the
worst West Nile year ever, yet they don’t think they have ever met anyone who
has had the disease. People say they
don’t know whether they ought to be worried, or just ignore it. Let me tell you
what I feel: I feel deeply appreciative
of the US Center for Disease Control’s (CDC) amazing ability to track rare and
novel diseases, knowing that someday, when a truly deadly new disease appears,
we will be warned and ready. Meanwhile,
I’m going to enjoy Michigan’s outdoors without undue fear.
West Nile Virus first appeared in the US in 1999 and is now
widespread. It is transmitted by the Culex mosquito and makes a variety of
mammals and birds ill. Most years there
are a few dozen human deaths from the disease in the US. It also kills horses and birds. There is no vaccine for the disease for
humans, but horse owners should get their animals vaccinated. Most people who get bitten by the Culex
mosquito never have any symptoms and may become immune to the disease. A few
people who get bitten become sick and go to the doctor and on rare occasions may
die. When you hear about the number of “cases” of West Nile Virus, it is these
people who have become very ill and have been tested who you are hearing about.
Not included in the number of cases are the thousands who actually had the
disease but had no symptoms.
This year the number of cases and deaths will likely be
double what we usually see. No one is
sure of the reason--maybe the mosquitos are doing better in the warmer weather.
There have been about 100 cases in
Michigan so far, and 4 deaths. Remember
that about 1,000 people are killed in car crashes in Michigan every year, and
nearly 30,000 die from heart disease.
Comparing the numbers you can see that even with the increase, West Nile
is not a big a threat at this time.
People ask if we should spray for mosquitos or put chemicals
in ponds to kill larvae. Some
municipalities in Texas have started doing that. In general, this is likely to
do more harm than good. Effective
mosquito control programs are carefully managed, and have good historical data
to guide local governments on what works, what is harmful to the environment,
and what is just a waste of money. It is
almost always the case that rushed anti-mosquito programs don’t kill enough mosquitos
to make a difference. If West Nile deaths
continue to climb, mosquito control could be part of a prudent response. But it would have to be done wisely to have
any real benefit, and to avoid harm to the environment.
There are some people who should not get bitten by mosquitos, because West Nile Virus could harm
them. The very old, infants, and people
with illnesses like diabetes, a heart condition or an immune disorder should
take precautions including wearing long sleeves, using repellant, and staying
indoors at dawn and dusk. Everyone else
should remember that healthy outdoor exercise will prolong their lives and head
out the door confidently. Don’t let the
headlines scare you into staying inside.