Volume 3, Number 44 - January 29, 2004
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Brucellosis-free status lost
Wyoming State Veterinarian Dr. Jim Logan announced in a Thursday morning press conference that a second group of cattle infected with brucellosis had been discovered in a Worland feedlot and Wyoming will soon lose its brucellosis-free status, although state officials planned to argue the matter.
Logan said although the state has been dealing with one infected herd near Boulder since November, he had begun to get the feeling that Wyoming "had dodged a bullet."
Then the news came in from the state vet lab last Tuesday that six more cattle had been found that tested positive for the disease. If there is any good news, it's this: the cattle originated in the original Boulder herd and the feedlot they were found on is a terminal feedlot, so at least that impact will be minimal.
The Worland feedlot is currently under quarantine. The 530 animals that have come into contact with the six infected cattle may not be moved until they are slaughtered.
Logan explained that as part of the epidemiological traceback from Doc Jensen's herd at Boulder, it was learned that 12 head of cattle in the Worland feedlot had left the Jensen herd on Oct. 27. Since leaving the Jensens', the cattle had changed ownership at least two times, landing in the feedlot where they were being fattened for eventual slaughter. Tests revealed that six of the 12 animals originating in the Boulder herd had very high titer reactions. All of the animals, with the exception of one, had been vaccinated. The cattle were mixed aged, so some had been vaccinated with the Strain 19 vaccine, and others had been vaccinated with the RB51 vaccine.
Although the cattle originated in Jensen's herd, the change of ownership to a feedlot meant that the infected animals technically became Wyoming's second infected herd.
"It will result in a loss of Wyoming's brucellosis-free status," Logan said, but Wyoming won't officially lose its status until a notice has been published in the Federal Register, a process that will take about two weeks to occur.
Because the loss of the status is imminent, Logan said, Wyoming needs to begin to satisfy additional brucellosis testing requirements. Testing will need to occur within 30 days prior to a change of ownership on all test-eligible cattle (sexually intact animals at least 18 months old) within the state's borders. Exemptions to the testing requirements include animals going directly to slaughter.
While the loss of the brucellosis-free status is a downgrade to Class A status, it's not a devastating to the livestock industry in Wyoming, "It is certainly a blow that we didn't need to have," Logan said. Class A status means that Wyoming cattle will be held to a different level of testing than prior to the class-free status.
The impact will be felt statewide for at least a year, Logan said. The impact will be the cost of testing all breeding animals prior to change of ownership, which Logan said is a "huge factor in marketability."
Wyoming has been classified as brucellosis-free for 18 years.
Logan said all the traceback work from the original herd is "very close" to being complete, although he is still awaiting word from Nebraska animal health officials on a final traceback.
"Apparently they went to slaughter," Logan said.
"To the best of our knowledge, all the animals (from the Jensen herd) have been accounted for," Logan said. He added that the epidemiological investigation "won't end until we're 100 percent satisfied that all the animals have been accounted for."
Logan said that late the night before the press conference, he had notified all the states of the change in Wyoming's situation.
Logan said he predicted that within the next year, "The livestock industry will step up to the plate and do what's necessary."
After a year of having no additional cattle test positive for the disease, Wyoming can again apply for its brucellosis-free status.
During that time, Logan said, Wyoming can work on educational efforts, working with livestock producers and industry groups to have producers implement best management practices to prevent the disease from re-occurring in the high risk area, which includes wherever there are elk feedgrounds, including Teton, Lincoln and Sublette counties. These include vaccination, testing, prudent purchasing and "spatial and temporal separation of livestock from wildlife."
"It doesn't mean the vaccination isn't effective," Logan said, emphasizing that the vaccine is about 70-80 percent efficacious. Since the cattle had been vaccinated, Logan said, they had apparently had "a huge overwhelming dose of the field strain bacteria," which could have occurred as the result of a single elk abortion event.
Logan said there isn't much the Jensens could have done to have kept from having their herd become infected, aside from moving, since their private ranch is adjacent to an elk feedground.
"At this stage of the game, we can definitely say that there was not a cattle source," Logan said of the Boulder herd infection. In the absence of the addition of infected cattle into Jensen's herd, Logan said, obviously the search for the source of the infection must turn to wildlife and the adjacent elk feedground.
Logan said he has asked the Wyoming game and Fish Department to test elk at the Muddy Creek elk feedground adjacent to the Jensen ranch near Boulder. If there are positive reactors to the test, Logan said, some elk will be euthanized and tissues samples taken for culturing. Testing is expected to begin this week.
The original 31 animals in Jensen's herd that were found to be infected were taken to the state vet lab in Laramie where they were euthanized, tissue samples were taken, and the carcasses were autopsied and incinerated. The remainder of the Jensen's breeding herd was sent to slaughter.
It should be emphasized that this is not a food safety issue. The infected animals were not put into the human food chain, and even if they had been, brucellosis is a bacteria that is killed in the normal cooking process.
"There is no risk of brucellosis being transmitted from food to people," Logan confirmed.
Logan said a federal station review of Wyoming's brucellosis status will come at his request, but it's not known when, except it will likely take place some time this year.
The state administration also reportedly planned to request APHIS reconsider downgrading Wyoming's brucellosis classification, since both infected herds are the result of the disease occurrence in a single herd. Since a change of ownership had occurred at least twice for the six cattle that tested positive on a Worland feedlot last week, under federal regulations, those animals constitute a second infected herd, even though the animals had originated in the Boulder herd discovered to be infected in November.
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