Babesia - Life Cycle

Life Cycle

The life cycle of Babesia microti, which is typical of parasites in that genus, requires a biological stage in a rodent or deer host, and is transmitted by ticks of the family Ixodidae between these hosts. To begin, the ticks introduce the sporozoites into the rodent when taking a blood meal. Sporozoites enter erythrocytes in the blood and begin the cyclical development between trophozoites and merozoites. Rather than producing more trophozoites, some merozoites produce gametocytes. The tick definitive host takes up the gametocytes when attached for a blood meal. The gametes are fertilized in the gut of the tick and develop into sporozoites in the salivary glands. The sporozoites are introduced into a human upon inoculation at the bite of an infected tick. Even as an incidental host, the phase changes which occur in the parasite are the same within humans as in the biological hosts. Babesia can be diagnosed at the trophozoite stage, and can be transmitted from human to human either through the tick vector or through blood transfusions.