title: Giardia duodenalis cysts of genotype A recovered from clams in the Chesapeake Bay subestuary, Rhode River.
abstract: Filter-feeding molluscan shellfish can concentrate zoonotic and anthroponotic waterborne pathogens. Cysts of Giardia sp. were detected by immunofluorescent antibodies in tissues of the clams Macoma balthica and M. mitchelli from Rhode River, a Chesapeake Bay (Maryland) subestuary. Molecular tests identified the cysts as Giardia duodenalis Genotype A, the most common genotype recovered from humans. Macoma clams are burrowers in mud or sandy-mud substrata and preferentially feed on the surface sediment layer. Waterborne Giardia cysts settle rapidly to the bottom in slow-moving waters and contaminate the sediment. Macoma clams do not have economic value, but can serve as biologic indicators of sediment contamination with Giardia sp. cysts of public health importance. These clams can be used for sanitary assessment of water quality.
authors.affiliation: Department of Molecular Microbiology and Immunology, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.
authors.forename: T K
authors.initials: TK
authors.lastname: Graczyk
authors.forename: R C
authors.initials: RC
authors.lastname: Thompson
authors.forename: R
authors.initials: R
authors.lastname: Fayer
authors.forename: P
authors.initials: P
authors.lastname: Adams
authors.forename: U M
authors.initials: UM
authors.lastname: Morgan
authors.forename: E J
authors.initials: EJ
authors.lastname: Lewis
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000469:parasitology*; D017931:DNA Primers / Q000737:chemistry; D016054:DNA, Protozoan / Q000737:chemistry; D019084:Fluorescent Antibody Technique, Indirect / Q000662:veterinary; D005838:Genotype; D016829:Giardia lamblia / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D005873:Giardiasis / Q000635:transmission*; D006458:Hemolymph / Q000469:parasitology; D008396:Maryland; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012623:Seawater; D017422:Sequence Analysis, DNA; D014876:Water Pollution
chemical_list: D017931:DNA Primers; D016054:DNA, Protozoan