Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum. Fever, chills, muscle aches, brain fog, and headache are common symptoms, but bleeding issues, organ failure, and respiratory failure can occur in the later stages of the illness. While nearly every infection causes white blood cells to increase, white blood cells go down with anaplasmosis. Elevated liver enzymes and low platelets are other diagnostic indicators of infection.