Submitted to: American Society of Parasitology
Publication Type: Abstract Only
Publication Acceptance Date: 3/11/2003
Publication Date: 8/14/2003
Citation: Fayer, R., Lewis, J., Trout, J.M., Santin, M.D., Zhou, L., Xiao, L., Howard, D., Palmer, R.C., Ludwig, K.A. 2003. Cryptosporidium found in the watershed, estuarine, and coastal waters of the United States. [Abstract]. Meeting of American Society Of Parasitology, August 1-6, 2003, Halifax, Nova Scotia. p. 2.
Technical Abstract: Previous studies have shown that oysters at 13 sites in Maryland's Chesapeake Bay, 9 open to commercial harvesting, were contaminated with Cryptosporidium oocysts. A 3 yr study found increased numbers of contaminated oysters following rainfall events. Molecular studies identified 4 Cryptosporidium species in oysters. Oocysts were detected in cattle and adjacent runoff from fields. Oocysts also were detected in shellfish growing waters impacted by sewage outfalls, septic systems, and wildlife, reflecting the presence of human and animal fecal contamination. Potential environmental and public health concerns prompted a wider study into coastal waters. Oysters and hard clams were obtained from retail markets in 2001 and 2002. Shellfish were examined at 49 collection sites (33 oyster and 16 clam) from New Brunswick, Canada and Maine to Florida to Texas. Oocysts were detected in shellfish from New Brunswick, 11 of 13 Atlantic, and 1 of 4 Gulf coast states. Of 1225 oysters and clams examined by IFA microscopy 4% harbored Cryptosporidium. Cryptosporidium DNA was detected by PCR in 35.2% of 185 pools of Atlantic shellfish and 1.7% of 60 pools of Gulf shellfish. Cryptosporidium parvum, C. hominis, and C. meleagridis, all infectious for humans, were found in shellfish from 59% (29/49) of the sites by either microscopy or molecular assays. This one-time sample, acquired during a period of drought, is thought to under estimate the prevalence of Cryptosporidium in these coastal waters.