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about screwworm eradication.
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USDA Celebrates Research That Eradicated the
Screwworm By Alfredo Flores
August 28, 2002
TUXTLA GUTIERREZ, MEXICO, Aug. 28--U.S. Department of Agriculture officials today
joined Mexican agriculture officials in commemorating the 30th anniversary of
the Mexican-American Commission for the Eradication of Screwworm and in
recognizing the commission's success in eradicating the pest from the United
States and Mexico.
"The successful eradication of the screwworm from the United
States and Mexico has saved numerous lives and prevented countless losses in
the livestock industry throughout North America," said Agriculture Secretary
Ann M. Veneman. "The commission should be commended for its valiant efforts and
resounding success--not only in these two nations, but throughout Central
America as well."
On Aug. 28, 1972, the Mexican-American Commission for the
Eradication of Screwworm was formed at the request of Mexican livestock
producers, to carry the program south to the Isthmus of Tehuantepec. The
commission, made up of an equal number of members from Mexico and the United
States, includes USDA employees from the Animal and Plant Health Inspection
Working with the commission, APHIS managed to establish a
barrier at that point in 1984, but cases remained in Mexico until 1986. The
Mexican-American commission, in cooperation with other commissions formed with
each Central American country, has eradicated the screwworm from virtually all
of Central America down to the Isthmus of Panama. Today a permanent sterile fly
release barrier is maintained in Panama between the Panama Canal and the
The commission eradicated the pest through methods including
sterile fly dispersal, surveillance, quarantine, and wound treatment. The
principle approach still used in this eradication program is the sterile insect
technique (SIT), a form of biological control.
USDA's Under Secretary for Marketing and Regulatory Programs
Bill Hawks is leading the USDA delegation and is speaking at today's
International Screwworm Symposium and Celebration Day.
Knipling developed the sterile insect technique. More about Knipling...
The Acting Administrator of USDA's Agricultural Research Service
(ARS), Edward B. Knipling is also
addressing symposium participants. His father, the late ARS entomologist Edward
F. Knipling, along with the late ARS entomologist Raymond C. Bushland,
developed SIT to suppress screwworms by sterilizing male flies with low-dose
irradiation and releasing them to mate with fertile females. Such matings do
not produce fertilized eggs, so numbers of insect offspring plummet
Other speakers included retired Congressman Kika de la Garza
(D-Texas), who served 13 years as Chairman of the House Agriculture Committee;
Dr. Gustavo A. Rodriguez Heres and Dr. John B. Welch, current directors of the
commission; and U.S. Ambassador to Mexico Jeffrey Davidow.
The commission worked with partners such as the Southwest Animal
Health Research Foundation (SWAHRF) to successfully eradicate the screwworm
from the United States.
USDA officials estimate that U.S. livestock producers benefit by
more than $900 million each year from the screwworm eradication program.
The National Agricultural Library (NAL) has produced a 10' by 10' exhibit for
the symposium and distributed a CD-ROM and brochures from its
Special Collections--all of
which describe the story of screwworm eradication. More information on NAL's
Screwworm Eradication Collection can be found at:
Screwworms are parasites that can cause great damage to domestic
livestock and other warm-blooded animals. The larvae of this pest enter open
wounds of the host animal and feed on the raw flesh. Rare cases of humans being
infested with screwworm have been reported. The United States has been free of
screwworm since 1966.