Babesiosis is a rare parasitic disease that can be passed to humans by deer ticks.

Babesiosis may not always cause symptoms. When symptoms are present, they usually start 1 to 4 weeks after the tick bite. Symptoms of babesiosis include:

• A general feeling of illness (malaise).
• Decreased appetite.
• Tiredness.
• Fever, chills, and sweats that come and go.
• Muscle aches (myalgias).

Babesiosis usually is treated with antibiotic medicines.