cryptosporidium exposure associated with crabbing within urban baltimore watersheds cynthia...

Cryptosporidium exposure associated with crabbing within urban Baltimore watersheds

Cynthia McOliver, MPH

Johns Hopkins University Bloomberg School of Public Health

2007

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

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

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)

Results: Part 1

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Sam

ple size (N

)

Type of recreational water activity reported

Figure 1. Self-reported recreational water contact in patients of the JHU Moore AIDS Outpatient Clinic, Baltimore, MD

Pilot Survey Followup Survey

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

Results: Part 2a: Soft Crabs

Figure 2. Raw counts of viable Cryptosporidium oocysts from control handwashes

n = 3

4

11

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3

11

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Control #1Handwash set 1

Control #1-Handwash set 2





Handwash sample type

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Figure 3. Raw counts of viable Cryptosporidium oocytsts from hands of soft crab handlers (n= 2)

19

43

21

1

0

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Handler 1 pre crab-handling Handwash

Handler 1 post crab-handling Handwash

Handler 2 pre crab-handling Handwash

Handler 2 post crabhandling Handwash

Results: Part 2b: Middle branch/Patapsco River Blue Crabs

Figure 4. Cryptosporidium in blue crab samples from Middle Branch-Patapsco River

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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

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

cryptosporidium exposure associated with crabbing within urban baltimore watersheds cynthia...

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