28th ANNUAL EASTERN FISH HEALTH WORKSHOP April 21-25, 2003 Prevalence And Intensity Of Mycobacterial Infection In Striped Bass From The Chesapeake Bay: A Comparative Study Using Histology, Bacteriology, and Molecular Methods Ilsa M. Kaattari, Martha W. Rhodes, Howard I. Kator, Dave E. Zwerner, Wolfgang K. Vogelbein, and Stephen L. Kaattari Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA  23062 The current epizootic of mycobacteriosis in wild striped bass from the Chesapeake Bay has been investigated since 1997.  To date, investigators at the Virginia Institute of Marine Science have examined over 2,100 striped bass from numerous sites in the Chesapeake Bay. During 2001-2002, a study was conducted to concurrently compare three methods for detection of mycobacteriosis: histology, quantitative bacteriology, and PCR/Nested PCR amplification of a conserved segment of the 16S rRNA gene.  Fish were collected either from recreational fishing tournaments ranging from the mouth of the Bay (Virginia Beach) to the Potomac River or from haul seine net surveys done in the York River.  Fish were transported on ice to the laboratory and aseptically necropsied immediately upon return.  For the whole dataset (N=118), quantitative bacteriological culturing and PCR techniques detected similar high rates of infection.  Both methods were more sensitive than the histological method.  Overall, 75% of striped bass sampled showed splenic mycobacterial infection, with the predominant isolate being Mycobacterium shottsii, a new species phylogenetically determined to belong to the M. tuberculosis clade.  The molecular method of detection, PCR/Nested PCR, was thus successfully validated as a useful, sensitive, and rapid method of detection for mycobacteriosis in wild striped bass. Return to 28th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page