Anthrax kills two cows in Becker County
The Minnesota Board of Animal Health confirmed Tuesday that two cows on a Becker County farm died last week of anthrax, the first anthrax cases in 2008.
Dr. Randy Lindeman, Frazee, who is the district veterinarian for the Board of Animal Health, said in a telephone interview that the infected herd was "in southwest Becker County," but declined to pinpoint the exact location.
After the dead cows were discovered on pasture, a blood sample was collected and sent to the North Dakota State University Veterinary Diagnostic Laboratory in Fargo. Tests confirmed the samples were positive for anthrax. The herd was not vaccinated for anthrax this year.
"In recent years, anthrax has been found in northwestern Minnesota but it is important to understand that western Minnesota does have a history of anthrax and producers should seriously consider anthrax vaccinations for grazing animals," said Board of Animal Health Senior Veterinarian Dr. Linda Glaser.
According to Lindeman, immunization of cows against anthrax "is cheap, safe and effective." Cattle producers should contact their local veterinarian for more information.
The infected Becker County herd will remain under quarantine for 30 days following the day the last death occurs from anthrax. However, Lindeman noted, anthrax is not viral in nature, and neighboring herds should not be affected.
Anthrax is a naturally occurring disease caused by the bacteria Bacillus anthracis, Lindeman continued.
To prevent further spread of the disease, the herd is usually moved to a different pasture, where "whatever the conditions were that caused this (disease) to manifest probably won't be replicated exactly in the next pasture -- even right across the fenceline," he said.
Because of this, Lindeman feels this latest outbreak of the disease will most likely be an isolated incident.
"I think this will prove to be an isolated case -- something of a fluke," he said.
All warm-blooded animals are susceptible to anthrax, but cattle, sheep, and goats are the most commonly affected species. In rare cases, humans can contract anthrax after handling or eating infected products, but this disease is not spread by animal-to-animal (or human) contact, Lindeman emphasized.
Animals are most likely to be affected by anthrax in the summer, while out on pasture.
"Typically what we have seen (of anthrax cases) in the past is in very dry or wet years," Lindeman noted. "In wet years, the water floats the spores up out of the soil and disburses them... in dry years, the animals have to graze closer to the ground, and can inhale dust that has anthrax spores."
Although it is unusual to see a case of anthrax so early in the year, these animals were on pasture in an area where cases had been detected in the past -- as is often the case, Lindeman said.
This is because the spores that contain the anthrax bacteria can lie dormant in the soil for a very long time.
"They are able to withstand the environment for years, perhaps even as much as decades," Lindeman said. When the soil is stirred up, the dormant spores can become active again.
Treatment of a cow infected with anthrax is pretty simple, Lindeman added -- but only if you catch it early enough.
"If it's in a vegetative state -- growing and multiplying inside the animal -- it is actually very treatable," he said. "It's easily killed with penicillin, but anthrax also produces several different toxins --toxins that can cause an animal to succumb pretty rapidly."
Any animal that dies suddenly of an unknown cause in western Minnesota should be treated as an anthrax suspect. Producers should contact their veterinarian immediately so blood samples can be submitted for testing.
If anthrax is confirmed, any remaining animals should be vaccinated and treated. Necropsies should not be performed on suspect carcasses, as the procedure can result in contamination of surrounding soil. All suspect cases of anthrax must be reported to the Minnesota Board of Animal Health at 651-201-6831.