Situation i andrew loves to go camping and hiking in the fall. about two weeks after his last camping trip, he noticed an expanding red rash on his arm. andrew is most likely suffering from

andrew is most likely suffering from: Lyme disease.
Lyme disease is a type of illness that's spread by a type of ticks called Borelia.  If someone got infected by this disease, they will show several symptoms such as muscle and joint ache, headache, rashes and in some cases it will cause fever.

It's considered to be association or connection