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Cryptosporidium exposure associated with crabbing within urban Baltimore watersheds Cynthia McOliver, MPH Johns Hopkins University Bloomberg School of Public Health 2007
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Introduction : Recreational Water Activities Recreational water activities are important to people and communities all across the United States –Fishing/angling, crabbing, boating, swimming and related activities In our area, the Chesapeake Bay and its tributaries support both recreational activities and subsistence activities Baltimore waters such as the Baltimore Harbor, Patapsco, Jones Falls and Gunpowder are popular sites Photo credits: Top: http://www.nps.gov/cbpo/planyourvisit/outdooractivities.htm; Middle: Personal photo; Bottom: US Fish and Wildlife Service Eufaula National Wildlife Refuge in Alabama
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Baltimore, MD: Urban setting for fishing and crabbing Our waters are receiving pathogens (bacteria, viruses, parasites eg Cryptosporidium) from many sources: –Point source: Human waste water treatment effluents –Nonpoint sources: Combined and sanitary sewer overflows Storm/rain event runoff Animals/pets Some of these pathogens cause human sickness such as gastroenteritis from foodborne/waterborne exposure Photo credit: top, leaking sewage main, http://www.ci.baltimore.md.us/government//minority/images/MBEoutreachWWP.pdf; Bottom: Immunofluorescently stained Cryptosporidium oocysts, H.D.A Lindquist, U.S. EPA
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Studies: Part 1 Question: Are persons with HIV/AIDS at risk of exposure to Cryptosporidium from recreational water contact? –Questions regarding type/frequency/location of water contact, residence, age, ethnicity, consumption of local catch, GI symptoms, handwashing etc –Premise: Persons with HIV/AIDS and other immunosuppressions are likely to develop severe/chronic illness from infections from Cryptosporidium (Colford et al., 1996 Am J Epidemiol. 1996 Nov 1;144(9):807-16; Chen et al., N Engl J Med. 2002 May 30;346(22):1723-31 ) –Recreational waters in Baltimore area, caught fish and handwashes from anglers have been found to be positive with Cryptosporidium (Roberts et al., J Toxicol Environ Health A. 2007 Sep;70(18):1568-76; Sunderland et al., Water Res. 2007 Aug;41(15):3483-9)
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Results: Part 1
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Studies: Part 2 Question: Is Cryptosporidium detectable from crabs (hard, soft), water samples, and handwashes? Experiment 1: Commercial Chesapeake soft crabs Experiment 2: Middle Branch Park-Patapsco River blue crabs
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Results: Part 2a: Soft Crabs
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Results: Part 2b: Middle branch/Patapsco River Blue Crabs
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Conclusions Recreational water contact and a high level of consuming self-caught or wild caught fish and crabs from local waters occurs in persons with HIV/AIDS in Baltimore. Blue crabs were shown to be contaminated with low levels of Cryptosporidium. Recreational water activities and handling of crabs are possibly a source of exposure to Cryptosporidium for persons with HIV/AIDS in our area. Sustaining the safety of our local waterways, food organisms and protecting human health requires cooperation between regulators, WWTP, local and state government, citizens, and watershed and other environmental organizations
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Acknowledgements The JHSPH Center for a Livable Future (Funding) Advisors: Dr. Ellen Silbergeld, Thaddeus Graczyk, a Dr. Richard Moore, Director; the patients and staff of the JHMI Moore Clinic, East Baltimore Leena Tamang, Field sampling & Lab analysis Carol Resnick (IRB help, survey design) Preety Gadhoke (survey design) Sean Evans, Hanna Blum, Marisa Caliri (survey administration and entry) Ruth Quinn & Ellen Wells (survey beta testers) Volunteers: Renee, Mark, Ellen, Priscilla & friend
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