Cabin Fever (2003)

Five students decide to top off their final college year by heading into the mountains to a rented cabin for a summer of frolicking in the wilderness. Unknown to them, a mysterious flesh eating virus has infected a local hermit who seeks refuge with the teens in their cabin. With symptoms ranging from uncontrollable rage to vomiting copious amounts of blood, the gang accidentally kill the hermit while fending him off... only problem being, one of them has contracted the virus, and it's only a matter of time till the fever spreads among them.