TO:
Mayor Mundy
City Council
City Manager
This brief memorandum is intended to raise public
awareness of the sources of the mosquito nuisance we face each summer, and more
effective steps each of us can follow to reduce the nuisance.
Until about eight years ago, the City of Sycamore
annually paid a private contractor to perform a variety of services including
the spraying of larval development sites and the more general “fogging” of
residential subdivisions. This service cost the City about $16,000 to $20,000
per year. In the preparation of the FY99-00 Budget, the benefit of such
treatments was researched in detail and the Council elected to cease spraying.
Among the sources contacted were the Illinois Department of Public Health, the
DeKalb County Health Department, and the Centers for Disease Control and
Prevention. More recent research confirms the results of the earlier review.
According to the independent analysis of
professional entomologists familiar with the mosquito nuisances in our area, the
pests we would be spraying are of two basic types: the floodwater mosquito and
the vector mosquito. Floodwater mosquitoes are among the most vicious biters and
usually appear about two weeks after a period of heavy rains. They can travel up
to 10 miles from where they hatch along prevailing winds. In a city surrounded
by tens of thousands of acres of farmland spotted by brackish water and
meandering streams, the effective abatement of such pests by spraying is simply
impractical. Vector mosquitoes are of two types: the Culex which bite from dusk
to dawn, and the tree-hole, which bite during the day. Culex mosquitoes breed in
bird baths, gutters, moist planting areas, old tin cans, and any location that
holds water. Both of the common vector types of mosquitoes have a narrower
habitat than the floodwater mosquitoes, but winds can carry them for several
miles. Again, in a small urban area proximate to vast agricultural land, the
spraying of such pests is going to have limited, if any, effectiveness.
Any community has to be aware of mosquito-borne
diseases. The most dramatic of these is probably encephalitis. Culex mosquitoes
can carry one strain of this disease which they pick up by biting birds affected
with the virus. Tree-hole mosquitoes carry the strain that has been more
prevalent in Illinois. This latter type infects small woodland animals such as
chipmunks and squirrels and when passed to humans the result can be severe
headaches and high fever. The most susceptible humans are children, older
adults, and persons with compromised immune systems. The last major encephalitis
outbreak in Illinois was 1975, when 47 deaths were reported. Since the
mid-1990s, less than a dozen cases of actual encephalitis were confirmed among
Illinois residents. If local health providers or County officials reported any
instances of confirmed encephalitis symptoms, our city and adjoining cities
could elect to spray any known larval sites, if they could be identified.
Another risk posed by mosquitoes under certain
circumstances is the transmission of West Nile virus. Culex mosquitoes also
carry this disease by feeding on infected birds and transmitting the virus to
humans and animals through bites. West Nile virus has been in the national news
since 1999, when the first case was detected in the Western Hemisphere. The
first case was identified in the Chicago area in 2001. The virus cannot be
transmitted from person to person, or from a pet to a human.
The Centers for Disease Control and Prevention
explain that the best protection against exposure to more serious symptoms as
well as the more general nuisance of mosquito bites is some common sense
measures:
Ø
Eliminating
places where mosquitoes breed, such as standing water on flat roofs or in rain
gutters, bird baths, stored boats, pet bowls, children’s wading pools, hollow
stumps, ornamental water gardens, etc.
Ø
Keeping
weeds and grasses cut short—these shady places are resting places for
mosquitoes.
Ø
Spraying
shrubbery around homes prior to prolonged activity in and around them.
Ø
Limiting
outdoor exposure, particularly that of children, in prime mosquito areas.
For its part, the City’s Public Works department places larvicidal briquets in the City’s catch basins when standing water is present over a prolonged period. Training in the use of such preventive action has been provided to the City’s Public Works employees by the DeKalb County Public Works department. The recent storms scoured the City’s catch basins of any mosquito infestations in such drainage structures, but monitoring will continue. For the present, the greatest risk of bites is in yard areas and the common sense steps noted above will serve us better than any spraying.
CC: Department Heads
Local Media