Kansen 5 - The Daybreak Episode 1

Oogami Island is normally a peaceful isle with lush green scenery, but is now a place of depraved wanton lust. The contagion Unknown - Level 4 has become epidemic. 3 girls, Hyuuga Natsu, Ochi Akari, and Hanazawa Airi find themselves trapped in a sports facility where they are assaulted by the infected.