The parasitic dinoflagellate Hematodinium infects marine crustaceans

Hematodinium is a type of parasitic dinoflagellate that infects marine crustaceans globally. The parasite lives mainly in the hemolymph or hemocoels of affected hosts, and results in mortalities due to malfunction or loss of functions of major organs. In recent years, the parasite had developed into an emerging epidemic pathogen not only affecting wild populations of economically valuable marine crustaceans in western countries but also the sustainable yield of aquaculture of major crabs in China. The epidemics of the parasitic diseases expanded recently in the coastal waters of China, and caused frequent outbreaks in aquaculture of major crab species, especially Portunus trituberculatus and Scylla paramamosain. In addition, the pathogen infected two species of co-cultured shrimps and multiple cohabitating wild crabs, implying it is a significant threat to the sustainable culture of commercially valuable marine crustaceans. In particular, the polyculture system that is widely used along the coast of China may facilitate the spread and transmission of the pathogen. Thus, to provide a better understanding of the biological and ecological characteristics of the parasitic dinoflagellate and highlight important directions for future research, we have reviewed the current knowledge on the taxonomy, life cycle, pathogenesis, transmission and epidemiology of Hematodinium spp. Moreover, ecological countermeasures have been proposed for the prevention and control of the emerging infectious disease.