Infectious diseases affect many populations and it should be natural to avoid contacts with infected individuals to prevent contagion. Recognizability of infected individuals is essential for infection avoidance. In the case of sexually transmitted infections, such avoidance is accomplished by choosing a healthy mating partner. We find that different mating strategies arise as a consequence of evolution of infection avoidance. Considering infection avoidance as host willingness to accept infection risk upon encountering a potential yet infected mating partner, we show that evolutionary bistability occurs: either no avoidance evolves or a degree of avoidance is attained at which the host population ends up disease-free. In the latter case, evolutionary suicide may even occur so that the host population goes extinct. Infection avoidance may also be driven by a degree of infection visibility and therefore thought of as a parasite trait. In that case, parasite crypticity (and hence no avoidance) evolves provided there is no cost on the degree of infection (non-)visibility. Considering a virulence-visibility trade-off leads to parasite crypticity, too, and no virulence. On the other hand, an intermediate degree of infection visibility becomes an evolutionary attractor if a transmissibility-visibility trade-off is adopted, or when the transmissibility-visibility trade-off and the virulence-visibility trade-off act simultaneously.

传染病影响许多人群，应避免与受感染者接触以预防传染，这是自然而然的。感染个体的可识别性对于避免感染至关重要。对于性传播感染，可以通过选择健康的伴侣来避免。我们发现，由于避免感染的进化，出现了不同的交配策略。将避免感染视为宿主在遇到潜在但已感染的交配伴侣时愿意接受感染风险的证据，我们表明发生了进化的双稳性：要么没有避免，要么达到某种程度的避免，使得宿主群体最终无病。在后一种情况下，进化性自杀甚至可能发生，从而使宿主种群灭绝。一定程度的感染可见性也可能导致避免感染，因此将其视为寄生虫性状。在这种情况下，只要不增加感染（不可见）程度的成本，就可以发展出寄生虫的隐秘性（因此无法避免）。考虑到毒性与可见性之间的权衡也会导致寄生虫的隐秘性，并且没有毒性。另一方面，如果采用可传播性与可见性之间的权衡，或者同时采用可传播性与可见性之间的权衡，则中等程度的感染可见性将成为进化的吸引子。考虑到毒性与可见性之间的权衡也会导致寄生虫的隐秘性，并且没有毒性。另一方面，如果采用可传播性与可见性之间的权衡，或者同时采用可传播性与可见性之间的权衡，则中等程度的感染可见性将成为进化的吸引子。考虑到毒性与可见性之间的权衡也会导致寄生虫的隐秘性，并且没有毒性。另一方面，如果采用可传播性与可见性之间的权衡，或者同时采用可传播性与可见性之间的权衡，则中等程度的感染可见性将成为进化的吸引子。