Mortality Secondary to Milky Hemolymph Syndrome Attributed to a Rickettsia-Like Organism in Two Japanese Spider Crabs (Macrocheira kaempferi) Housed in a Public Display Aquarium in North America
Abstract
Rickettsia-like organisms (RLOs) have caused significant disease and losses in aquaculture systems of molluscs and decapod crustaceans, but are not reported in display aquaria. Infections with a variety of different rickettsia-like organisms (RLO) have been previously identified in numerous marine invertebrates, especially molluscs and decapod crustaceans.1-3 The term RLO is a morphologic designation for several unrelated intracellular, gram-negative, alphaproteobacteria that form intracytoplasmic inclusions in tissues. While some RLO infections are incidental findings, others, such as withering abalone syndrome caused by Candidatus Xenohaliotis californiensis, can have devastating consequences on wild populations or aquaculture systems.4 Japanese spider crabs, Macrocheira kaempferi (JSCs), are a large, charismatic species displayed at many institutions within the Association of Zoos and Aquariums (AZA) and around the world. This case report details two mortalities in Japanese spider crabs (Macrocheira kaempferi) in an aquarium setting in North America. Treatment with enrofloxacin and oxytetracycline was performed on one crab which died despite treatment. Diagnostic investigations of a healthy conspecific included water testing and hemolymph sampling for cytology and PCR analysis for RLOs.
*Presenting author
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