OVERVIEW OF BUMPER CAR DISEASE - IMPACT ON THE NORTH-AMERICAN LOBSTERFISHERY

Recent (1993) landings of American lobsters (Homarus americanus) were valued at $294 million (Can.) in Canada and $213 million (Can.) in the United States, However, post-harvest losses are estimated at $50-75 m illion (10-15%) annually, The lobster fishery is one of the few remain ing viable traditional fisheries in eastern North America, ''Bumper ca r'' disease of lobsters, caused by the scuticociliate Anophryoides hae mophila, can cause significant losses in coldwater impoundments, Appar ently epidemics now occur more frequently and with greater severity; s urprisingly the epidemiology and economic impacts of ''bumper car'' di sease are not well documented. The ciliate A. haemophila is easily mai ntained in a cell-free, chemically defined, seawater-based medium at 5 degrees C. Cultured ciliates require longer and more parasites to kil l lobsters than those transmitted by intrahaemocoelic injection from l obster-to-lobster, Regardless of source of ciliates, the larger the in oculum, the more rapid the death of lobsters. The pathogenesis of ''bu mper car'' disease is unknown. Horizontal transmission could occur acr oss the thin cuticle of gills or via wounds in the exoskeleton present during moulting of lobsters. Because ciliates are initially sequester ed in lobster tissues for an extended period, they are detectable soon er by histological examination of tissues than by direct examination o r culture of haemolymph. Additional to indirect fluorescent antibody t esting and immunoperoxidase staining of tissues, utilizing monoclonal antibodies prepared to sonicated ciliates, the parasites are readily d etected with oligonucleotide probes based on ssu-rDNA of A. haemophila . The prevalence of A. haemophila should be re-evaluated, Ciliates seq uester in gill, heart and muscle tissues. Several disinfectants and ch emotherapeutants, licensed in North America for veterinary use in food -producing animals, are efficacious against A. haemophila in vitro. A definition of healthy vs ciliate-infected lobsters is being prepared, based on haematology and clinical chemistry of haemolymph. Our novel b ar-coded labelling system for aquatic organisms facilitates experiment al design and randomization protocols of lobsters, The model of ''bump er car'' disease will aid study of health and infectious disease proce sses of lobsters and other crustaceans. (C) 1997 Australian Society fo r Parasitology. Published by Elsevier Science Ltd.