Before revision:  The rate of cooperation within a population is directly linked to the rate of spread of the disease . Unfortunately, evolutionary game dynamics predict that all individuals evolve to 'defect. ' Here, we combine the disease dilemma with the compartmental model used for diseases which do not confer immunity .
After revision:  The rate of cooperation within a population is directly linked to the rate of spread of the disease , cooperation evolves under certain conditions. For diseases which do not confer immunity .