I went overland through the ME, Pakistan, India/Ceylon in 1963, and periodically, (every few years or so), have a recurrence of what I suspect might be malaria, but have never been able to verify it.*
It starts with an overwhelming urge to stretch every bone in my body, then progresses to saturated sheets from sweating, thence to uncontrollable shivers.
*A few years ago, in Ottawa, I visited a walk-in clinic while in the aftermath stage, (can't go anywhere while it's happening), and consulted with a doctor originally from India who, from his experiences there, said it sounded like malaria.........blood tests were run but nothing was identified, (which, from researching, I've found is not uncommon...numerous tests can be run before getting a positive hit).