Ehrlichiosis is an infectious disease caused by bacteria from the genus Ehrlichia, which are transmitted to humans through bites from infected ticks. The disease primarily affects white blood cells, leading to symptoms such as fever, headache, fatigue, and muscle aches. Diagnosis is typically made through blood tests, and treatment usually involves antibiotics like doxycycline. If left untreated, ehrlichiosis can lead to severe complications, including respiratory failure or organ damage. Preventive measures include avoiding tick bites by using insect repellent and wearing protective clothing in wooded or grassy areas.