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United States Department of Agriculture

Agricultural Research Service

Healthy Animals Newsletter

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Issue 9, August 2001
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The Role of Wildlife in Animal Disease Control

While many livestock and poultry diseases can be researched and controlled exclusively by working with the specific animal of concern, others can only be understood by incorporating wildlife into the research and risk assessment.

For example, raccoons serve as a source of rabies infection in the Midwest, while birds play a key role in the transmission of West Nile virus to horses and humans. ARS studies the role of wildlife in several diseases important to agriculture: tuberculosis, brucellosis, lyme disease, malignant catarrhal fever, transmissible spongiform encephalopathies, pine needle abortion, avian influenza, and Newscastle disease.

In some cases, wild animals serve as a direct reservoir for the infectious agent. Bison and elk in Yellowstone National Park carry the bacterium that causes brucellosis in cattle. In 1956, 124,000 cattle herds tested positive for brucellosis. This year, there are no known cattle herds with brucellosis thanks to a cooperative USDA and state eradication program. But as long as bison and elk serve as havens for the bacteria, there’s always potential for the disease spilling back over to cattle.

Other eradication programs, such as for bovine tuberculosis, also suffer from wildlife carriers. The existence of these diseases causes trade barriers. These barriers won’t be overcome until the disease is not only eradicated from livestock, but scientists can devise methods to prevent reintroduction from wildlife.

Studying wildlife also helps researchers assess the risk that a disease will spread. Avian viruses such as those that cause influenza, Newcastle disease, and avian pneumovirus can pass back and forth between wild and domestic birds. But only some virus strains cross species. By understanding which viruses are likely to spread with wild birds, researchers can develop strategies to reduce exposure and transmission.

Also, when scientists identify a new virus in poultry, they can look at their data on wild birds to help discover the virus’ origin, as well as the likely direction in which it will spread.

And the research may one day help local economies. For example, deer infected with tuberculosis in Michigan and elk with chronic wasting disease in the West create hunting-related restrictions that greatly dampen local economies as well as threaten agriculture. MCF affects many animal species, especially exotic deer and related animals in zoological parks.

Research on chronic wasting disease may help define if and how a prion disease can cross species-- key to overcoming trade issues associated with spongiform encephalopathies and helping to ensure that the United States remains BSE-free.

Because wildlife and the diseases they carry do not observe human boundaries, ARS has a key national research role--along with the USDA’s Animal and Plant Health Inspection Service--to help state agricultural agencies manage disease outbreaks. ARS also has the containment facilities that allow them to study infected animals and the disease agents, as well as veterinarians with specific expertise in these diseases.

For more information on ARS wildlife disease research, contact:

Diana Whipple or Keith Murray, (515) 663-7200

Don Knowles, (509) 335-6022

David Swayne, (706) 546-3433

Research Briefs

ARS scientists have cracked the biochemical code of the chicken herpesvirus that causes Marek's disease--that could help in creating new vaccines against the poultry disease.
Sanjay Reddy
(517) 337-6830

Piglets grew about 12 percent faster in their first 18 days of life than did other pigs when they were given a one-time injection of the anti-inflammatory agent dexamethasone, according to ARS research.
Jeffrey Carroll
(573) 882-626

Measuring immune system messengers--called cytokines--is answering basic questions about how pigs and cattle respond to infection or stress. Researchers can use information from this ARS research to design targeted therapies that stimulate the desired response.
Joan Lunney
(301) 504-8201

An ARS research project to determine the prevalence of anaplasmosis, babesiosis, and theileriosis in Morrocan livestock will help producers in that country as well as help standardize testing procedures for these diseases internationally.
Willard Goff
Donald Knowles
(509) 335-6029

ARS' patented "four-poster" device is the basis for controlling ticks on white-tailed deer in the Northeast. In Maryland, populations of blacklegged tick nymphs dropped 59 to 71 percent.
J. Mathews Pound
(830) 792-0342
John Carroll
(301) 504-9017

ARS animal ethologists hope to help prevent accidental crushing behavior in pigs and encourage less agressive behavior in cattle while feeding. They are seeking clues to these behaviors by undetected observation of the animals.
Julie Morrow-Tesch
(806) 742-4214

New clues about the role of hormones and genetics in birth weight may help reduce dystocia in heifers. ARS research on birth weight, feeding, and sire contribution have already helped breeders greatly reduce the problem.
Michael MacNeil
(406) 232-4970


These ARS researchers have been honored recently for their achievements:

ARS Honor Awards:

Mohammad Koohmaraie , Meat Animal Research Center, for developiing first rapid tests for detecting pathogens on beef, pork, and poultry carcasses, as well as techniques for reducing E. coli O157:H7 in red meat.

S. Karl Narang and David Swayne, Southeast Poultry Research Laboratory, as part of the West Nile Virus Team, for outstanding and dedicated efforts in developing a strategy for addressing issues related to surveillance, diagnostics, and prevention of the West Nile Virus in the Western Hemisphere .

Bailey Mitchell, Southeast Poultry Research Laboratory, received a Federal Laboratory Consortium award for designing an electrostatic space charge system that removes dust and microorganisms from the air of poultry-producing facilities.

About This Newsletter

ARS Animal Health Research Laboratories

Healthy Animals Archive

Last Modified: 2/6/2007
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