Final answer:
Plasmodium malariae is the malaria parasite known to specifically affect old red blood cells, whereas P. falciparum, the most deadly form, infects RBCs of all ages.
Step-by-step explanation:
The type of malaria that affects old red blood cells (RBCs) is caused by the Plasmodium malariae parasite. Unlike P. falciparum, which infects RBCs of all ages and is the most deadly, P. malariae specifically targets older RBCs. This characteristic is part of the parasites' strategy to survive within the host, and it also influences the clinical manifestations and treatment approaches for the infection. P. falciparum is responsible for the majority of severe malaria cases and deaths, and it infects red blood cells indiscriminately, leading to a high rate of cell turnover and severe symptoms. Management of malaria involves antimalarial drugs and supportive care, as malaria can lead to anemia, organ failure, and death if left untreated.