Pneumocystis carinii causes primary infection in: (A) Rats, (B) Mice, (C) Humans, (D) Rabbits
Answer is A. There are two known species of Pneumocystis - Pneumocystis carinii, commonly found in rats and Pneumocystis jirovecii seen in humans. Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition