South Dakota
mosquitoes are well known thanks to the construction of the Gavins Point
Dam near Yankton in the 50's.
Mosquitoes breed in water and public health officials then were worried
that some mosquito species may increase in numbers along with the dam
construction.
Mosquitoes were surveyed near the Lewis and Clark Reservoir in 1954 (just
prior to the closing of the dam), in 1956 (just after closing of the dam),
and in 1958 when the reservoir pool reached normal operating level.
The early mosquito surveys were a cooperative effort of the U.S. Army Corp of
Engineers, the U.S. Public Health Service, South Dakota Department of
Health, and the Nebraska Department of Health.
This interesting historical account can be found in a publication entitled
"Mosquito Study, Lewis and Clark Reservoir, Summer of 1960"
authored by John Edman who was then a Research Assistant at the University
of Nebraska in Lincoln.
Dr. Edman is currently Director of Vector-Borne Disease Research and
Professor of Entomology at the University of California-Davis.
To date, the most complete publication about South Dakota mosquitoes is
"South Dakota Mosquitoes and Their
Control" authored by former Entomologist Dr. Richard W. Gerhardt
and published by the SDSU Agricultural Experiment Station in 1966.
Dr. Gerhardt went on to work for the Centers for Disease Control (CDC) in
Atlanta, GA after his stint as Associate Professor of Entomology at SDSU
in the late 60's.
South Dakota has 43 species of
mosquitoes. And nineteen of these species have already been found positive for the West Nile virus elsewhere
in the United States, and may therefore act as potential vectors of the West
Nile encephalitis in the state.
Update
August 1, 2002:
The first West Nile virus positive mosquitoes in South Dakota were
collected
from Brookings County between July 8 to July 11, 2002 by the SDSU
Mosquito Surveillance Team headed by Dr.
Mike Hildreth.
According to Mike, the WNV-positive mosquitoes were Culex
tarsalis. Culex tarsalis is present
in every single SD county.
Update
August 13, 2002:
Culiseta
inornata and Mansonia (Coquillettidia)
perturbans have been found WNV-positive somewhere in the United
States. These two species are known to be present
in South Dakota.
Update
September 23, 2002:
The CDC has recently updated their
list of mosquito species found positive for the West Nile Virus.
Based on the CDC report and comparing the species list with what mosquito
species we have here in South Dakota, we now have a total of 19
mosquito species that can potentially transmit the West Nile Virus in
the state.
A WNV-positive mosquito species does not immediately incriminate that
particular species as a competent vector of the virus that causes West
Nile encephalitis in humans. Vector competence can only be confirmed
by controlled disease transmission studies. Any volunteers?
References:
Edman, J. 1961. Mosquito study, Lewis and Clark Reservoir,
Summer of 1960. Nebraska
State Department of Health, Division of Sanitation. Lincoln.
Gerhardt, R. 1966.
South
Dakota mosquitoes and their control. South Dakota State University
Agricultural Experiment Station Bulletin 531. Brookings.
CDC Division of Vector-Borne Infectious Diseases.
|
