News 2011
Where Have the Blue Crabs Gone? AFDC Seminar
Tue, 17 May 2011
Aquaculture and Fisheries Development Centre,
School of Biological, Earth and Environmental Sciences,
Seminar Series
Where Have the Blue Crabs Gone? New Approaches to Disease Discovery in Blue Crabs and other Aquatic Species
Marc E. Frischer
http://www.skio.usg.edu/people/frischer/
Professor, Skidaway Institute of Oceanography, Savannah, Georgia, USA
Professor II, University of Bergen, Norway (UNI Research)
Wed 18 May 1.00 pm G13 Cooperage
Recently (1997-2004) in coastal Georgia USA and much of the eastern USA coast blue crab (Callinectes sapidus) populations were severely impacted by an epizootic caused by the parasitic dinoflagellate Hematodinum sp. Because of this drought associated disease event and the difficulty of studying this parasite and its disease ecology, we developed several parasite-specific PCR-based diagnostic assays that allow the rapid and unambiguous detection and quantification of Hematodinium in blue crabs, in water, and in other animal reservoirs. This assay has simplified the investigation of the life cycle and etiology of hematodinium-disease. However, it is apparent that newly emerging or newly identified diseases in estuarine and marine ecosystems are increasingly responsible for negatively affecting ecosystem health, wild fisheries, and aquaculture, and it remains a great challenge to identify and investigate these unknown and emerging disease agents. Recently, we developed a new approach for detecting and identifying known and unknown parasites of the blue crab. Denaturing high-performance liquid chromatography (DHPLC) is used in combination with peptide nucleic acid (PNA) blocking oligonucleotides to detect PCR amplified 18S rDNA gene fragments from parasites against a background of host (crab) DNA. The validity of this assay was confirmed in the blue crab/Hematodinium model system. During these studies several new blue crab infections were detected including infection by a Kinetoplastid tentatively classified in the family Bodonidae. To our knowledge this is the first report of this group of parasites in any decapod crab. Kinetoplastid parasites are common in many vertebrate species including fish and humans.