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United States Department of Agriculture

Agricultural Research Service

Healthy Animals Newsletter

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Issue 13, December 2002
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Research Targets Livestock Pests

ARS uses various strategies to deal with different arthropod-borne viruses (arboviruses) and parasites. Researchers might seek to stop a pathogen a pest is carrying, treat a resulting disease or focus on managing populations of the pest itself. They might take all of these approaches and more.


An ARS National Program, Arthropod Pests of Animals and Humans (#104), addresses problems concerning a range of insects, including ticks, flies and mosquitos. Researchers are concerned with pests indigenous to the United States, while also seeking methods to assess and suppress potential risks from invasive pests outside U.S. borders.

Arthropod-borne pathogens pose potential risks for epidemic disease to the U.S. livestock industry. The presence of some disease-carrying pests can lead to restrictions on the exportation of animals and animal products from the United States, and can lead to higher prices in the domestic market.

Sterile male screwworm fly: Link to photo informationScrewworm flies' flesh-eating maggots parasitize livestock, wildlife and humans. ARS researcher Edward F. Knipling first developed a theoretical sterilization technique in 1937 to control the screwworm. The technique involves irradiating male insects, then turning them loose to mate with wild fertile female insects. These matings don't produce fertilized eggs, so numbers of insect offspring drop dramatically.

Knipling demonstrated in the early 1950s that the male screwworm could be sterilized. His colleague, Raymond C. Bushland, proceeded to develop this idea, which eventually resulted in the eradication of screwworms from the United States, Mexico and Central America. Today, the technique is used worldwide to eradicate outbreaks of other pests such as Mediterranean fruit flies and tsetse flies.


Researchers at ARS' Midwest Livestock Insects Research Unit in Lincoln, Neb., are working to develop a male-only strain of screwworms to mate with females in the wild. They are also preserving screwworm germplasm and enhancing screwworm rearing for eradication programs. A new field diagnostic kit developed at the lab differentiates screwworm fly maggots from similar fly species that are not so harmful to cattle.


Knipling is remembered as the "founding father" of areawide integrated pest management (IPM). Realizing total eradication is not feasible for most pests, he developed the concept of using specific insect parasites, predators, and other tactics over a broad area to keep pest populations below the point where they are a financial burden on farmers and ranchers. Kept at low levels, pests are more responsive to biological, rather than chemical control.


At the Knipling-Bushland U.S. Livestock Insects Research Laboratory in Kerrville, Texas, the legacy of these pioneers continues as ARS works to control the cattle fever tick with a variety of methods. Research has identified two independent mechanisms by which the ticks become resistant to a class of pesticides. The Kerrville scientists are also developing and improving laboratory tests to identify pesticide-resistant ticks. The scientists have patented an invention, known as the four-poster, that uses bait to lure deer to self-apply pesticide to their heads, where most ticks feed. This device will help control cattle fever in the Southwest and Lyme disease in the Northeast.


The Kerrville researchers are teaming with scientists at the ARS Animal Disease Research Unit in Pullman, Wash., in spearheading the first tick genome project. They hope to learn more about the protozoa in the Babesia genus that causes cattle fever.


The Arthropod-Borne Animal Diseases Research Laboratory in Laramie, Wyo., is another ARS lab working to diagnose and control domestic livestock diseases transmitted by arthropods. Currently, the most economically important arthropod-borne disease of U.S. livestock is bluetongue disease (BLU). The biting midge transmits BLU and the related epizootic hemorrhagic disease (EHD) viruses to ruminant livestock. The presence of BLU viruses in the U.S. has resulted in restrictions on the movement of livestock and livestock germplasm to BLU-free countries. The Laramie research unit is assessing the role of arthropods in the transmission of these viruses and others, such as West Nile virus. They developed the first single genetic test to distinguish all five types of the virus that causes bluetongue in the U.S. and developed rapid tests that distinguish bluetongue from EHD.


Pesticides and drugs used for the control of pests and pathogens can pose threats to the health of animals and humans. ARS is developing safe, effective and user-friendly methods to detect, monitor and control pests in ways that are safe for the environment.


For more information, contact the following researchers:


Philip J. Scholl, Lincoln, Neb.
John E. George, Kerrville, Texas
Richard T. Mayer, Laramie, Wyo.

Research Briefs

A breakthrough test developed by ARS scientists allows for detection of bovine tuberculosis with just one blood sample. The assay also works for some other mammals.
Wade R. Waters
(515) 663-7756
Mitchell V. Palmer
(515) 663-7474

ARS scientists and cooperators sequence the genome of the bacterium causing Johne's disease.
John P. Bannantine
(515) 663-7340

Vivek Kapur
(612) 625-7736

Researchers at ARS trying to increase the number of offspring pigs produce in the United States have found that Meishan pigs of Southern China have an abundance of a hormone that aids in the production of sperm.
Johny Joe Ford
(402) 762-4184
Gary A. Rohrer
(402) 762-4365

ARS scientists helped a high school class save a sheep flock with a genetics-based strategy that uses an innovative test for a debilitating disease of the nervous system.
Katherine O'Rourke
(509) 335-6020

Scientists from around the world are joining ARS in developing a Bacterial Artificial Chromosome (BAC) map to help identify genes that affect production traits in cattle and aid in sequencing the bovine genome.
Steven M. Kappes
(402) 762-4109

John Keele
(402) 762-4251

ARS scientists and cooperators discovered a mutated sheep gene that might help researchers further map the human genome and provide clues to the role of certain genes in human health.
Brad Freking
(402) 762-4278

Farm-raised channel catfish receive protection from a deadly fish parasite with a new treatment against its vector.
Andrew J. Mitchell
(870) 673-4483
Link to videoVideo


Awards

Benjamin M. Rosenthal of the Parasite Biology, Epidemiology and Systematics Laboratory has won ARS' T.W. Edminster Research Associate Award for his top-ranked proposal to study how similar parasitic species are related to one another and how to tell them apart.

Landmark research on livestock parasites recently earned former ARS researcher K. Darwin Murrell a place in the agency's Science Hall of Fame. Murrell and two other ARS scientists were inducted into the agency's annual program recognizing outstanding career achievements in agricultural science.

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ARS Animal Health Research Laboratories

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Last Modified: 2/6/2007
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