Mango, this might sound strange, but could it be Toxoplasmosis? This is a virus and it settles (goes dormant) in the nervous system. Severe flu like symptoms.....in fact, the symptoms are harder than the flu. My boodhound, The General got it (from a cat in the neighborhood). The General didn't eat the cat, but evidently the cat's poop and cats are carriers, but not infected. I remember gardening one day and stepping in cat poop in my front yard. We both got it. I couldn't get out of bed for two days......muscle aches, felt like a train had hit me. About a week later The General couldn't move, was in pain and was temporarily paralyzed. The Vet did a spinal tap to detect the problem. Steriods (other stuff, too) fixed him up, but it was touch and go for him.
The Vet told me then that humans can get this and more than 40% test positive for the antibodies, which means we've been infected. This is also why pregnant women are not ever supposed to handle litter boxes, etc.
Anyway, upon reading your last post, it triggered this memory and this info. might help the physician! Best wishes and I sincerely hope his fever is down immediately! That's still very, very high! ;-)