Babesia is a genus of protozoa that infect the blood and cause a parasitic, hemolytic disease known as babesiosis. Transmission is via the Ixodes tick, the same species that often carries Borrelia burgdorferi (the cause of Lyme disease), and thus coinfection with these two parasites may occur in a patient. The endemic region is the northeastern United States. People who contract babesiosis suffer from malaria-like symptoms, such as hemolytic anemia and fever. Individuals without a spleen are at increased risk for severe disease. Microscopic analysis may show a ring form or "maltese-cross" within red blood cells. Treatment is with Atovaquone and azithromycin.