Controlling anaplasmosis by Bob L. Larson, DVM Anaplasmosis is a disease of cattle that has historically been a problem in the southern parts of the United States. Reports of cattle affected by the disease have gradually spread north so that now, cattlemen in many important beef-producing areas need to be aware of this problem. The disease is caused by a parasite that attaches to red blood cells which causes the animal's body to destroy the cell. If enough red blood cells are destroyed, anemia can result.
Blood samples taken from affected animals appear to be watery.
Sometimes affected animals become excited and aggressive when not enough oxygen reaches the brain. Cattle of any age can become infected, but the severity of illness increases with age. In cattle that are three years of age or older, the death rate is 30 to 50 percent in animals that display clinical signs. Anaplasmosis is primarily spread from animal to animal by insects that take large blood meals, such as ticks and horseflies. Other biting insects such as stable flies and mosquitoes can also transmit the disease, as can human activities such as dehorning, tattooing or vaccinating which could transfer the blood of an infected animal to another individual.