Fig. 4

Scheme of immune responses in bovines infected with Babesia parasites. A Schematic of innate immunity. Innate immune responses in young calves are characterized by the swift activation of macrophages and the abundant release of interferon-γ (IFN-γ) and nitric oxide (NO). Young, naive calves have a natural resistance to Babesia infection and typically survive exposure to Babesia-infected ticks in endemic areas. In contrast, adult animals are more susceptible to Babesia infection, which often results in acute and fatal babesiosis. However, if animals survive the acute infection, they may develop chronic babesiosis and produce life-long protective immune responses. Additionally, the innate immune response is more pronounced in young animals compared to adult animals. B Schematic of adaptive immunity in persistently infected or vaccinated animals with live attenuated vaccine. Macrophages and protective neutralizing antibodies are deemed critical for controlling parasitemia in these animals