Fig. 4 in Myxosporean parasites in Australian frogs: Importance, implications and future directions

Fig. 4. Hypothetical life cycle and transmission routes of Cystodiscus species. Understanding of the life cycle and timing of infection will provide invaluable information to wildlife disease managers to mitigate the impact of myxosporean parasite. The majority of myxosporean parasite life cycles alternate between a vertebrate host and an invertebrate host, in the case of Cystodiscus it is frogs and an unknown invertebrate (green box) (1). The vertebrate host sheds myxospores (grey square, right) that infect an invertebrate host that produces actinospores (grey square, left) (2). Actinospores are the infective stages for vertebrate hosts (frogs). It is unknown at what stage of development amphibians are susceptible to infection (3), Cystodiscus spp. have been found in both tadpoles and adults. It is possible that spawn, tadpole, metamorph or an adult frog can be infected by actinospores (red arrows, green outlined square). It is unknown if infection can be shed during development or if it is passed on during metamorphosis or spawning (blue arrows, green outlined square).