THINGS I'VE SEARCHED: Wiki'd "Zoonotic Illnesses" (thinking a vector-borne illness would be a good choice) and searched the resulting relevant diseases (including, but not limited to, leptospirosis, Western Equine Encephalitis, and rabies). Googled various combinations of "1800s" "vector-borne" "disease" "illness" "historical" etc. Read relevant sections of multiple 1800s historical disease websites (sorry, the links are on my other computer) and books (that I own).
SETTING: United States, Washington territory, 1870-1880. Area is mostly wooded (though being cut down for logging), with a small town beginning to spring up at the edge.
CHARACTER: Male, 20-25, strong and healthy. Lives in a log cabin most of the time, and at a camp in the mountains occasionally. Works as a logger. Rides horses frequently. Drinks, doesn't smoke, sexual habits unknown. (If anyone can think of any other info that might be relevant, chances are I either know it, or can make it up.)
The disease MUST:
-- be infectious (as opposed to intrinsic), but CANNOT be easily communicable. The sick character has to be the only one struck down by the illness.
-- not be the result of injury; must come about unexpectedly.
-- be serious enough that people around him would fear he might die.
-- be able to be recovered from without long-term aftereffects, even in the absence of professional medical attention. (The doctor will be reachable by telegram, to give suggestions or instructions, but not at the scene.)
-- not be of a recurring type (like malaria).
-- cause a fever, preferably a reasonably high one.
-- preferably not involve gastrointestinal symptoms, as they would complicate things in multiple ways.
I've been thinking that Rocky Mountain Spotted Fever might work, but I'm not sure if there was RMSF as far west as what's now Washington State in the late 1800s, and I'm also having trouble finding any information about it dating to before current medical knowledge (treatment, survival rate, etc).
(And yes, for the record, I do know that it's quite likely that no one in my story is going to know the name of the illness--chances are, the character will be said to have "a fever" or "the fever"--but I still need to know what I'm giving him, so the symptoms and prognosis make sense.)
Thanks for any ideas/suggestions/opinions/links/etceter
EDIT: Apparently, sometime last night--I think as I was doing research on this, actually--my computer caught a virus that is now preventing me from using it at all. I PROMISE I will get back to each and every one of you, but it may not be until after the weekend. I am so sorry. Until then...thanks so much! :-)