Anaplasmosis is an infectious disease caused by the bacterium Anaplasma phagocytophilum, which is transmitted to humans through the bite of infected ticks. It primarily affects white blood cells, leading to symptoms such as fever, chills, headache, and muscle aches. The disease is most commonly found in certain regions, particularly in the northeastern and north-central United States. Early diagnosis and treatment with antibiotics are essential to prevent complications. If left untreated, anaplasmosis can lead to more severe health issues, including respiratory failure or organ damage.