A person infected with "love" mutates a little, becomes more open and depraved. Mutations can be amplified by conditions and time. A person can infect others through kissing. Mutated infected will hide their changes and try to behave as usual, but at the same time unobtrusively infect. But sometimes the infected can reveal their true form and forcefully infect. No clues about infected. Mutations can change the entire body or only part of it.