Which of the following diseases is caused by a protozoan?
Influenza
Babesiosis
Blastomycosis
Syphilis
Correct answer: Babesiosis
Solution
Babesiosis is caused by Babesia species, which are protozoan parasites that infect red blood cells. The other choices are caused by a virus (influenza), fungus (blastomycosis), and bacterium (syphilis).