There is one thing that amazes me in this world, diseases can get diseases. This works on more than one level, let me explain.
The microbe that causes malaria can itself be infected by a virus called a phage. The virus will kill the microbe just like a virus kills cells but this virus is not interested in your cells.
When you catch the cold virus your body makes antibodies, these are proteins that attach to the virus and block the viruses ability to infect cells. This is like catching a disease because the proteins interfere with the virus functions.
all I can say is wow