Many people who are infected with Babesia microti feel fine and do not have any symptoms. Some people develop nonspecific flu-like symptoms, such as fever, chills, sweats, headache, body aches, loss of appetite, nausea, or fatigue.

Because Babesia parasites infect and destroy red blood cells, babesiosis can cause a special type of anemia called hemolytic anemia. This type of anemia can lead to jaundice (yellowing of the skin) and dark urine.

Babesiosis can be a severe, life-threatening disease, particularly in people who

  • Do not have a spleen;
  • Have a weak immune system for other reasons (such as cancer, lymphoma, or AIDS);
  • Have other serious health conditions (such as liver or kidney disease); or
  • Are elderly.

Complications of babesiosis can include

  • A low and unstable blood pressure;
  • Severe hemolytic anemia (hemolysis);
  • A very low platelet count (thrombocytopenia);
  • Disseminated intravascular coagulation (also known as “DIC” or consumptive coagulopathy), which can lead to blood clots and bleeding;
  • Malfunction of vital organs (such as the kidneys, lungs, and liver); or
  • Death.
Page last reviewed: May 17, 2018