Did the friend get a positive diagnosis?
She saw a doctor (in Bishop or Mammoth, where she is living), got a diagnosis, and received drugs. I do not know what tests they did, or did not, do. My friend is a long time (decades) backpacker ... has done the JMT 4-6 times solo in large sections ... fairly sophisticated about this stuff.
Cottonwood is cattle country.... Was he/she treating the water?
Her actual route was Cottonwood Lakes TH-New Army Pass-Lower Soldier Lake-Cottonwood Pass TH. This trip was in August, and I was not on it (i.e., it was not the trip she did later with me over Labor Day).
She uses grapefruit extract to treat water, and nothing else. Makes me nervous, but that is what she does.
She is not a newbie to backpacking, as alluded to above. Rather, she is an old hand and is fairly sophisticated about where she chooses to fill up.
How many days after the start of the trip did the first symptoms occur?
I do not know. I do know that it was after the trip because she mentioned that.
I believe it was either 5 days/4 nights, or 4 days/3 nights, based on what she told me were her campsites.
Thanks,
Karin