Further contribution to the life history of Centrocestus formosanus (Nishigori, 1924) Price, 1932 (Trematoda: Heterophyidae) with special reference to a new first intermediate host from the South Western Ghats, India

Centrocestus formosanus is a zoonotic small invasive heterophyid fluke with worldwide distribution. Its three-host life cycle requires a thiarid snail as first intermediate host, fishes as second intermediate hosts and piscivorous birds and mammals as definitive hosts for completion. As far as is known, the only first intermediate host being utilized, globally, by this parasite is the snail, Melanoides tuberculata. In the present study, life cycle stages of C. formosanus were recovered naturally and successfully tested in the laboratory. Study also adds a new host to its life cycle, the snail Bithynia (Digoniostoma) pulchella, as the first intermediate host with natural infection. Parasitological descriptors (prevalence, mean intensity and mean abundance) of infection were measured for each host. Being an invasive parasite, addition of a new host to C. formosanus life cycle has notable ecological and evolutionary significance.