story to find out more.
John Ewart (left),
an aquaculture/fisheries specialist (University of Delaware), and ARS
microbiologist Gary Richards examine freshly harvested oysters on board the
Center for the Inland Bays' work boat before transport to the laboratory.
Click the image for more information about it.
Research Reveals Functions of Harmful Shellfish
Pathogens By Jim
Core March 4, 2005
Providing safer shellfish is the goal of Agricultural Research Service
(ARS) scientists who are studying the
means by which pathogenic bacteria enter shellfish.
In the United States, two pathogenic bacteria from the genus
Vibrio are of concern: V. vulnificus and V.
parahaemolyticus. These bacteria are naturally found in shellfish and
seawater, particularly when water temperatures are warm, and can lead to
serious health concerns.
ARS scientists at the
Safety of Aquaculture Products Center of Excellence in Dover, Del., are
studying these bacteria with the goal of keeping them out of shellfish.
Richards, a microbiologist and the center's lead scientist, wants to
identify Vibrio enzymes that may help the organism enter shellfish--and,
eventually, a human host.
Richards, who leads a group of scientists from
Delaware State University and the
National Institutes of Health, recently
discovered in V. vulnificus an enzyme called phosphoglucose isomerase.
This enzyme could provide a way for Vibrio to spread more easily.
He also detected the enzyme in virtually all species of Vibrio
tested, but not in non-Vibrio pathogens. The enzyme is capable of
producing what are called vasoactive peptides, which could contribute to rapid
spread of V. vulnificus in humans. A study of V. vulnificus in
oysters suggests that strains virulent to humans may be more invasive to--and
The Dover center, a field location of the ARS
Regional Research Center in Wyndmoor, Pa., also studies methods to detect
norovirus and the hepatitis A virus in shellfish. It also develops
high-pressure processing techniques to inactivate enteric viruses in
This research may provide better diagnostic capabilities and treatment
strategies to further reduce shellfish-related illnesses.
more about this research in the March issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.