USDA ends some brucellosis research

Select agent restrictions cited in the change
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Animal health authorities ended a brucellosis research project in two states after determining that regulations on biological threats require conducting any further work in secure laboratories.

Joelle R. Hayden, spokeswoman for the Department of Agriculture’s Animal and Plant Health Inspection Service, said the agency stopped research in Colorado and Montana on the effects of birth control on spread of brucellosis among bison and elk.

"That work proceeded as far as our current regulations allowed in the field, and the information gathered is being reviewed for potential publication," she said in a message. "APHIS will continue to support and collaborate with entities such as the USDA’s Agricultural Research Service and universities on brucellosis research, as they are better positioned to handle certain aspects of the research, especially with Brucella abortus listed as a select agent."

APHIS and the Centers for Disease Control and Prevention control access to select agents, biological agents or toxins that pose severe threats to public, animal, or plant health or products. B abortus is zoonotic and a substantial threat to livestock, and it is found among wild bison and elk in and near Yellowstone and Grand Teton national parks.

Montana’s state veterinarian, Dr. Martin Zaluski, said the USDA had been using a double-fence facility north of Yellowstone in Corwin Springs, Montana, to conduct brucellosis studies. The disease is spreading in the western U.S., he said, and recent research projects could have provided new tools to control that spread, tools that would not result from work in a laboratory.

With increasing incidence of brucellosis in cattle and domestic bison herds in the GYA in the past few decades due to transmission from elk, significant resources are needed to address a problem that is expanding in scale and scope. …

"Revisiting Brucellosis in the Greater Yellowstone Area," a report published in May 2017 by the National Academy of Sciences

Brucellosis causes abortion and weakness among calves, and it spreads through contact among animals and through infected remains from birth or abortion, APHIS information states. Reducing the pregnancy rate in wildlife could reduce disease transmission.

Dr. Keith Roehr, state veterinarian for Colorado, said his state had been home to brucellosis studies for at least two decades. An outdoor facility in Fort Collins had been used for research involving elk and bison before the decision. Large animals thrived in that environment better than he expects they would in a contained laboratory.

Dr. Roehr said he was familiar with studies on brucellosis transmission by elk and vaccines that could reduce spread of the pathogen from wild elk to other wildlife or livestock. Without new tools for disease prevention, he expects brucellosis will spread and endanger greater numbers of animals.

The National Assembly of State Animal Health Officials, in a July 14, 2017, letter to Agriculture Secretary Sonny Perdue, said brucellosis is an expanding zoonotic disease and the assembly was troubled by the decommissioning of brucellosis research in Montana and Colorado.

"Findings from prior research efforts have directly affected decisions relating to management of brucellosis including needed separation in time between the use of lands by infected wildlife and subsequent use by cattle, potential for remote vaccination of wildlife, and most recently, the ability of bull bison to transmit brucellosis," the letter states.

The assembly noted that the APHIS decision followed publication in May 2017 of the National Academy of Sciences report "Revisiting Brucellosis in the Greater Yellowstone Area." The report indicates infections in cattle and farmed bison are becoming more common, and brucellosis control efforts need to be focused on reducing transmission from wild elk.

The NAS-published report’s recommendations include conducting research that could help manage or reduce the risk of B abortus transmission. The research community should develop an improved brucellosis vaccine for cattle and bison and a vaccine and vaccine delivery system for elk, it states.

Other studies should improve understanding of brucellosis disease ecology, epidemiology, economics, detection, infection biology, and host immunity, the report states.

"With increasing incidence of brucellosis in cattle and domestic bison herds in the GYA in the past few decades due to transmission from elk, significant resources are needed to address a problem that is expanding in scale and scope; without the changes and investments necessary to aggressively address this problem in a coordinated and cost-effective manner, brucellosis may spread beyond the GYA into other parts of the United States resulting in serious economic and potential public health consequences," the report states. "Efforts to reduce brucellosis in the GYA will depend on significant cooperation among federal, state, and tribal entities and private stakeholders as they determine priorities and next steps in moving forward."

North Dakota’s state veterinarian, Dr. Susan Keller, who was the animal health assembly’s president when the letter was sent, said in an interview that the changes enacted by the USDA should be subject to a public comment period. She also questioned whether the change would increase safety.

The Agriculture Bioterrorism Protection Act of 2002 requires review of the select agents and toxins list every two years. Hayden noted that, in January 2016, APHIS officials published notice that they were proposing removal of B abortus and B suis from the select agent and toxins registration list, along with the Pasteur strain of Bacillus anthracis, Peronosclerospora philippinensis, Phoma glycinicola, and Sclerophthora rayssiae.

"There are either no viable samples in the U.S., no climate conducive to growth, or there is adequate treatment available for these agents," agency officials wrote. "By removing them from select agent regulations, APHIS is removing many of the restrictions on the possession, use and storage of these items.

"Of note, removing Brucella abortus from the select agent list will allow for additional research into vaccines for brucellosis."

​A bison calf in Yellowstone National Park (​Courtesy of U.S. National Park Service)

However, in the Jan. 19, 2017, Federal Register, APHIS and the CDC published separate notices indicating the agencies had decided against the proposed changes to the select agents and toxins list.

Dr. Keller said states with brucellosis have lost control options as depopulating stray wildlife has become unpalatable to the public. Landowners who bought their property for encounters with wildlife have refused entry during depopulation efforts, she said.

Separating wildlife and livestock—by area or time in an area—is a primary brucellosis prevention method, Dr. Roehr said. Infections still occur, and vaccines for wildlife would benefit livestock and livestock owners.

In October 2017, leaders of the U.S. Animal Health Association adopted a resolution urging allowances for brucellosis studies conducted under field conditions in endemic areas and using natural disease transmission. They also urged removing the select agent listing for B abortus.

USAHA information indicates researchers are no longer able to study vaccine responses to natural infections in cattle, elk, or bison, and brucellosis pathogenesis studies are possible only at a biosafety level 3 facility run by the USDA Agricultural Research Service in Ames, Iowa.

The USAHA resolution cites select agent regulations and a joint memorandum issued in August 2017 by the Department of Health and Human Services and the USDA. The APHIS memorandum states that, by Federal Select Agent Program policy, animals infected with select agents cannot be removed from nature to expose other animals to the agents, and naive animals cannot be moved to natural environments with the intent of exposing those animals to select agents existing in the environment.

Dr. Zaluski said the studies conducted in Montana and Colorado would be impossible in a BSL 3 facility. No such facility has the capacity to study, for example, 80 bison in containment, he said.

He also said that the brucellosis agent becomes more available to unauthorized people as natural infections increase.