Deterring Truly Infected Individuals
Dishonest signals of infection may help to keep legitimately infected
conspecifics at bay. Parasites often adaptively disrupt host defence
mechanisms against other infections (Wakelin 1984). For example,
helminths can suppress the immune response of their hosts in order to
improve their own survival (Maizels et al. 2004) which can cause
increased host susceptibility to other parasites (Helmby et al.1998; Su et al. 2005; Hartgers & Yazdanbakhsh 2006; Kamal & El
Sayed Khalifa 2006) or make the costs of infection more severe (Marshallet al. 1999; Graham et al. 2005). Thus, genuinely sick
individuals are predicted to exhibit heightened levels of disgust to
promote avoidance of further infection (Oaten et al.2009). By mimicking being
parasitized, a healthy individual could, therefore, deter truly infected
conspecifics and reduce their chances of becoming legitimately infected
(Loehle 1995).