Lonnie Gonsalves NOAA Cooperative Oxford Laboratory

Introduction Genus Description: TB vs. EM Microbial ecology Pathogenic mycobacteria in fish The Chesapeake Story Fish impacts Human impacts Continued research

Tuberculosis Complex M. tuberculosis, M. bovis, M. africanum, M. caprae, M. canettii, M. pinnipedii, and M. microti M. leprae

Environmental Mycobacteria Over 120 species outside of TB complex and M. leprae Aerobic, gram positive, acid-fast, non-motile, saprophytic Diverse environments: Marine and fresh water, treated municipal water, industrial hot water systems, hot tubs Multiple vectors: Insects, protozoa, amoeba Extremely hardy Chemical resistant Biofilm formation Primarily non-pathogenic

Pathogenic Mycobacteria in Fish 160+ fish species susceptible to infection Aquaria, aquaculture, and wild fish Fishbase.org

Mycobacterium spp. in wild fish (Jacobs et al a )

Symptoms External lesions Emaciation Pigment changes Visceral red foci “Pop eye” Enlarged/gran ular spleen Granuloma *Inter-specific variation in virulence and host response*

Macrophages: Home Sweet Home Intracellular survival ROS/chemical-resistant cell wall Prevent phago-lysosome maturation Alter inflammatory response Granuloma formation

Granuloma Formation Co et al. 2004

Granuloma Formation

Routes of Transmission Ingestion (Harriff, Bermudez, and Kent 2007) Water column (Li and Gatlin 2005) Open wounds Attachment of amoeba Transovarian (Conroy 1966)

Mycobacteriosis in the Chesapeake Bay Outbreak of dermal lesions in 1997 Attention from multiple research groups VIMS COL UMD-College Park MD DNR Mycobacterium spp. causative agent (Heckert et al. 2001; Rhodes et al. 2001) Age dependent infection rates (Kaatari et al. 2005) Prevalence > 70% in older fish M. shottsii primary isolate in striped bass Detected in archived tissues 1984 (Jacobs et al. 2009)

Prevalence over time

Mycobacteriosis in Striped Bass by Age 1998-present Mark Matsche, Maryland Department of Natural Resources

Mycobacteriosis by Age (Kataari et al. 2005) Collected in the Chesapeake Bay

Prevalence of lesions in wild- caught striped bass (Overton et al. 2003)

Alternative Hosts Kane et al. 2007

Impact on Fishery Rise in natural mortality during ongoing epizootic (Crecco 2003; Kahn 2004; Jiang et al. 2007) Increased estimates of myco.-induced mortality (Gauthier et al. 2008) Ubiquitous, not novel

Why Now? Nutrition Reduced growth Changes in foraging behavior

Nutrition and Progression of Mycobacteriosis (Jacobs et al b )

Why Now? Nutrition Reduced growth Changes in foraging behavior Water quality Nutrients Hypoxia Affect on alternate fish species

Impact on the Human Health Diseased fish less marketable Human health risk? Consumption of striped bass is NOT considered a disease risk Associated with handling fish/water contact health.asp

Conclusion Mycobacterium spp. infection increased Increased natural mortality within time frame Slow death Relatively low risk of human infection IF proper precautions considered Impact on other key fish stocks? Factors contribute to disease prevalence?

Questions?