Submitted to: Society of Protozoologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/10/2003
Publication Date: 6/17/2003
Citation: Fayer, R., Lewis, E.J., Trout, J.M., Xiao, L. 2003. Atlantic and gulf coast multi-state study of cryptosporidium in shellfish.[Abstract]. Society of Protozoologists Meeting. June 15-19, 2003, Glenden Beach, Oregon. p.1
Technical Abstract: Scientists from the USDA, NOAA, Johns Hopkins Univ. and the CDC previously found Cryptosporidium oocysts in oysters at 13 sites in Chesapeake Bay, MD; 9 open to commercial shellfish harvest. A 3 yr study found more infected oysters following rainfall events. Molecular studies identified 4 Cryptosporidium species in oysters, 2 found in outbreaks affecting humans. These findings reflect the presence of human and/or animal feces possibly from sewage outfalls, septic systems, or farm runoff into shellfish growing waters. Potential environmental and public health concerns prompted a wider investigation. To determine the prevalence of Cryptosporidium in U. S. coastal states, USDA, NOAA, and CDC scientists obtained oysters and hard clams from retail markets in 2001 and 2002. Twenty five shellfish were examined at each of 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. As a one-time sample, acquired during a time of drought, these results may or may not be indicative of the long-term prevalence of Cryptosporidium in coastal shellfish.