Who discovered malarial parasite

Driving after drinking is not advised because due to intoxication

Why is it that during changing weather, one is advised to avoid closed, crowded and airconditioned places like cinema halls etc. ?

Arthritis is the disease of

Person $^{\prime}A^{\prime}$ cannot step out of his house. He has to spend his entire life in sterile isolation otherwise, he would quickly contract a fatal infection. This person has almost no effective immune system. This disease is also called as baby in a bubble syndrome. Identify the disease, this person $^{\prime} A ^{\prime}$ is suffering from