What does jungle rot mean?

Slang term for a venereal disease, and/or form of crotch itch.

Definition

Also used to denote a fungal infection, usually one encountered by soldiers serving in tropical areas, where the feet would get wet, and not be allowed to dry properly, creating a fungal infection around the toes.

Duo meaning, among service personal, especially those who have served in tropical zones, such as Viet Nam.

Was popularized during WWII, by Marines serving on Guadalcanal Island.