The pathogenesis of <i>Hematodinium</i> spp. in decapod crustaceans – recent advances and unanswered questions

The dinoflagellates <i>Hematodinium</i> spp. are important endoparasites of a wide range of decapod crustaceans from across the globe. High prevalences of infection have been reported particularly in decapods of commercial importance including crabs and some lobster species. While such infections usually result in their death, the dynamics of these differ widely depending on location, the genotype of <i>Hematodinium</i> and host. This review aims to explore the interaction between these parasites and their hosts with particular emphasis on the diversity of host range, methods of detection, impact on fisheries and how this parasite multiplies within hosts without causing any apparent cellular immune response. Emphasis is placed on evaluating the future directions required to solve key unanswered questions of this increasingly important parasite.