Sennetsu fever or human ehrlichial infection is a rare bacterial infection caused by bacteria called Ehrlichia. Ehrlichia bacteria are transmitted through tick bites. Sennetsu fever can be a mild or a potentially life threatening disease. Symptoms usually appear within a few weeks of the tick bite and include sudden high fever, fatigue or feeling very tired, muscle pain, and headache. Other common symptoms may include chills, nausea, vomiting, diarrhea and red eyes. Most infected children and some adults develop a skin rash. During Sennetsy fever, the bacteria may target and kill white blood cells (part of our body's immune or defense system). If this happens the person will have a weaker immune system and may also become sick with other serious infections. Sometimes the bacteria will attack liver cells causing liver damage. Treatment of this disease involves antibiotics such as doxycycline or minocycline. For those who are allergic to these two drugs, rifampin is an alternative antiobiotic. The main prevention technique is tick control. Talk with your doctor if you or your child has been diagnosed with sennetsu fever to decide on the best treatment plan.