DAO 61:263-268 (2004)  -  doi:10.3354/dao061263

Response of American lobsters Homarus americanus to infection with a field isolate of Aerococcus viridans var. homari (gaffkemia): survival and haematology

A. L. Battison1,3,*, R. J. Cawthorn2, B. Horney1

1Department of Pathology and Microbiology, Atlantic Veterinary College, and 2Atlantic Veterinary CollegeLobster Science Centre, University of Prince Edward Island, 550 University Avenue, Charlottetown,Prince Edward Island C1A 4P3, Canada
3Present address: Atlantic Veterinary College Lobster Science Centre, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island C1A 4P3, Canada

ABSTRACT: American lobsters Homarus americanus were inoculated with a field isolate of the Gram-positive bacterium Aerococcus viridans var. homari, causative agent of gaffkemia, at 1 × 106, 1 × 104 or 1 × 102 colony forming units (CFU) kg–1 or with sterile 3% NaCl and maintained at 10 or 15°C until they died or were euthanised. Progression of disease in individual animals was monitored daily by total haemocyte count (THC) and haemolymph culture. Post-mortem examinations were performed on all lobsters. Effects of both ambient temperature and infective dose on survival time were observed. Marked bacteraemia occurred in all mortalities. Haemocytopenia (THC < 10 × 109 cells l–1) preceded death in most, but not all, mortalities.


KEY WORDS: Lobster · Homarus americanus · Gaffkemia · Aerococcus viridans var. homari


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