Nearly 60 cattle are dead in Colorado after an outbreak of anthrax, but officials are confident the disease has been contained.
The outbreak occurred at a ranch in Logan County and marked the first confirmed incidence of the disease in Colorado in 31 years. Anthrax outbreaks are not uncommon in the Western states and the risk of infection is minimal outside the affected ranch, said Colorado state veterinarian Keith Roehr, DVM.
Scientists from the Colorado State Veterinary Diagnostic Laboratory in Fort Collins confirmed the disease in the carcass of one of the deceased animals. Officials said they are certain “beyond a reasonable doubt,” based on the clinical signs, that the other cattle died from anthrax as well.
Officials quarantined the ranch, and cattle at nearby ranches are scheduled for vaccinations, and some may take prophylactic antibiotics as a precaution. Because no cattle left the Logan County ranch in the months before detection of the clinical signs of anthrax, infected cattle likely did not enter the food chain, according to the Colorado Department of Agriculture.
Drought conditions may have created a favorable environment for bacterial growth, Dr. Roehr said. The disease is caused by the spore-forming bacterium Bacillus anthracis. Livestock can become infected by ingesting spores while grazing.
Anthrax is considered a serious disease because it can cause the rapid die-off of a large number of animals, often with no illness detected in the dead animals, according to the Colorado Department of Agriculture.
People with open wounds can contract the disease by handling infected livestock or livestock products.
Veterinarians in Colorado should have anthrax on their minds when making differential diagnoses on cattle with clinical signs of the disease, Roehr noted. Clinical signs include fever, respiratory difficulty, excitement followed by depression, lack of coordination, vomiting, diarrhea, bloody discharges, convulsions and death, according to the American Veterinary Medical Association.