a lot of people
Malaria is a protozoa.
algae
There are no bacteria on other bacteria. Some bacteria do attack other bacteria by piercing their cell wall and injecting proteins. Viruses can attack bacteria. They are called bacteriophages.
protozoa is a unicellular, usually obligate intracellular parasite. bacteria has a rigid cell wall,peptidoglycan or LPS. and protozoa doesn't have it.