Transmission consequences of coinfection: cytokines writ large?
Trends in Parasitology 23: 284-291.
Co-infection of a host by multiple parasite species is commonly observed in nature, and recent epidemiological work suggests that co-infection can enhance parasite transmission. This review proposes an immunoepidemiological framework to understand how within-host interactions during co-infection might affect between-host transmission. Cytokines, immune signaling molecules with a fundamental role in the amplification of anti-parasitic effector mechanisms, provide a useful way to simplify immunological complexity for this endeavour: as argued here, focusing on cytokines offers analytical tractability without sacrificing realism. Testable predictions about the epidemiological consequences of co-infection are generated by this conceptual framework.