Babesia microti Life Cycle
The B. microti life cycle involves 2 hosts, a rodent, primarily the white-footed mouse, Peromyscus leucopus, and an Ixodes tick.
1. During a blood meal on a mammalian host, a Babesia-infected tick introduces sporozoites into the mouse host.
2. Inside the mouse host, sporozoites enter erythrocytes and reproduce asexually.
3. In the blood, some parasites differentiate into male and female gametes.
4–5. After gametes are ingested by a tick, the gametes transform into sporozoites.
6. Humans enter the life cycle when bitten by an infected tick. An infected tick introduces sporozoites into the human host during a blood meal.
7. Inside the human host, sporozoites enter erythrocytes and reproduce asexually.
8. Human-to-human transmission can occur through blood transfusions.
Image from the Centers for Disease Control and Prevention, Global Health, Division of Parasitic Diseases and Malaria.