Perkinsus sp. infection risk for Manila clams, Venerupis philippinarum (A. Adams and Reeve, 1850) on the Pacific Coast of North and Central America.ABSTRACT Manila clams (Venerupis philippinarum, A. Adams and Reeve 1850) are an important aquaculture aquaculture, the raising and harvesting of fresh- and saltwater plants and animals. The most economically important form of aquaculture is fish farming, an industry that accounts for an ever increasing share of world fisheries production. species on the west coast of North America North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. and are also cultured in Europe, Asia, and other locations. Clams cultured on the west coast of North America are thee of Perkinsus sp. infections, while clams from certain Asian and European sources are infected. Infection in Korean Manila clams is reportedly associated with high morbidity and mortality Morbidity and Mortality can refer to:
An agent that binds directly to a predefined sequence of nucleic acids. Mentioned in: Legionnaires' Disease DNA probe, n See deoxyribonucleic acid probes. for in situ hybridization in situ hybridization A method for localizing a sequence of DNA, mRNA, or protein in a cell or tissue; the use of a DNA or RNA probe to detect a cDNA sequence in chromosome spreads or in interphase nuclei or an RNA sequence of cloned bacterial or cultured . The use of this probe is validated and reported for the first time. As a result of this finding, no importation of this clam stock took place. It is urgently important to make widely known the risk of the spread of this disease into the clam stocks of the west coast of North and Central America Central America, narrow, southernmost region (c.202,200 sq mi/523,698 sq km) of North America, linked to South America at Colombia. It separates the Caribbean from the Pacific. to prevent such an introduction. In addition, we report new information regarding the prevalence and intensity of this disease in juvenile clams available for export, as well as pathologic features of the disease. KEY WORDS: Venerupis (Tapes) philippinarum, juvenile clam infection, Perkinsus sp., DNA probe, in situ hybridization INTRODUCTION Manila clams (Venerupis philippinarum, A. Adams and Reeve 1850) are an important aquaculture species on the west coast of North America. More than 7 million pounds of littleneck clams, predominantly V. philippinarum, were produced in Washington. California, and Oregon in 2000 (Pacific Coast Shellfish Growers Association 2003), and additional production occurs in British Columbia, Canada. Although Alaska produces native littleneck clams, Protothaca staminea (Conrad 1837), Manila clams are exotic, and importation for aquaculture purposes is prohibited. Venerupis philippinarum is also an important aquaculture species in Europe and Asia, and is infected with Perkinsus sp. on both continents. Specifically, Perkinsus atlanticus occurs in Europe (Navas et al. 1992), a P. atlanticus-like parasite occurs in Japan (Hamaguchi et al. 1998), and Perkinsus sp. occurs in Korea (Choi & Park 1997) and China (Liang et al. 2001). Consistent with the close homology homology (hōmŏl`əjē), in biology, the correspondence between structures of different species that is attributable to their evolutionary descent from a common ancestor. noted between DNA sequences at several P. atlanticus and Perkinsus olseni loci loci [L.] plural of locus. loci Plural of locus, see there by diverse investigators, Murrell et al. (2002) assert these parasitic species to be synonymous, with taxonomic priority to the P. olseni name. In contrast, clams from the west coast of North America are free of Perkinsus sp. infections. A survey of Manila clam health and conditions on the west coast of North America (Pacific Shellfish Institute 2001), and the required examination of over 3000 clams for health certifications from 1991 to 2002, showed no evidence of Perkinsus sp. infection. Moreover, such infections have not been reported elsewhere on the west coast during routine annual examinations and frequent health examinations of brood stocks and seed clams since 1985. In addition, Perkinsus sp. Infection has not been reported in the native littleneck clam P. staminea or any other bivalve bivalve, aquatic mollusk of the class Pelecypoda ("hatchet-foot") or Bivalvia, with a laterally compressed body and a shell consisting of two valves, or movable pieces, hinged by an elastic ligament. species from the west coasts of North or Central America. Manila clams may be imported as a live market product from Korea, Japan, or other Asian countries into North America. In 1998, we evaluated the health status of juvenile Manila clams from Korea that had been proposed for importation into Mexican waters, where they would gain size before shipment to the United States, either to market destinations or to receiving waters for further grow out. The examination of clams was performed as a preliminary assessment for a producer considering the importation of Korean Manila clams. We report the finding of a high prevalence of a Perkinsus sp. causing significant tissue damage in juvenile Korean Manila clams. As a result of this finding, no importation of this clam stock took place. It is urgently important to make widely known the risk of the spread of this disease to west coast North American North American named after North America. North American blastomycosis see North American blastomycosis. North American cattle tick see boophilusannulatus. clam stocks to prevent the introduction of this debilitating de·bil·i·tat·ing adj. Causing a loss of strength or energy. Debilitating Weakening, or reducing the strength of. Mentioned in: Stress Reduction and lethal clam parasite. In addition, we report here new information regarding the prevalence and intensity of this disease in juvenile clams that are available for export, as well as pathologic features of the disease. Finally, a novel genus-Perkinsus DNA probe for in situ hybridization (ISH ISH In Situ Hybridization ISH Isolated Systolic Hypertension ISH Irish Sport Horse ISH Intermediate System Hello ISH International Society of Hypnosis ISH Information Super Highway ISH International Superhits (Green Day album) ) assays on histologic samples is described. Taxonomic references to the Manila clam (also commonly referred to as the Japanese littleneck clam) in the scientific literature are particularly confusing. We have designated the species as V. philippinarum in accordance with the Committee on Scientific and Vernacular Names of Molluscs within the Council of Systematic Malacologists, American Malacological Union (American Fisheries Society 1998). The common name Manila clam is also found in the literature, apparently in reference to the same species, associated with scientific designations of Tapes philippinarum, Ruditapes philippinarum, Tapes semidecussatus, and Tapes japonica japonica (jəpŏn`əkə): see quince; camellia. . MATERIALS AND METHODS A total of 64 Manila clams [16-32 mm shell length (SL)] from Inchon Bay, South Korea, were clinically examined in February 1998 and were fixed whole in Davidson's shellfish fixative fixative /fix·a·tive/ (fik´sit-iv) an agent used in preserving a histological or pathological specimen so as to maintain the normal structure of its constituent elements. fix·a·tive adj. (Shaw & Battle 1957). These tissues were processed for routine histologic examination histologic examination The study of a tissue specimen by staining it and examining it by LM. See Light microscopy. . A representative tissue section containing parasites was evaluated by ISH. The genus-Perkinsus DNA probe was designed to specifically target SSU SSU Small Subunit SSU Sonoma State University SSU Savannah State University (Savannah, Georgia) SSU Shawnee State University (Ohio) SSU Salisbury State University rRNA sequences of Perkinsus species by aligning the available SSU rRNA gene sequences, while not hybridizing to the sequences of closely related parasite taxa taxa: see taxon. including dinoflagellates dinoflagellates minute aquatic protozoa; they produce red pigment and toxins which are taken up by shellfish without apparent ill effect, but the toxin is not metabolized and the shellfish may poison animals if eaten. and apicomplexans. An SSU rRNA gene sequence is not available for Perkinsus qugwadi. The resulting probe Perksp700DIG (5'-CGCACAGTTAAGTRCGTGRGCACG-3') was 5' end-labeled with digoxigenin (Sigma-Genosys, The Woodlands. TX). ISH assays were performed as previously described (Stokes & Burreson 1995, Stokes & Burreson 2001), except that 125 [micro]g/mL pronase was used for permeablization, instead of proteinase proteinase /pro·tein·ase/ (pro´ten-as?) endopeptidase. pro·tein·ase n. A protease that begins the hydrolytic breakdown of proteins usually by splitting them into polypeptide chains. K, for a 30-min digestion, and a probe concentration of 7 ng/[micro]l was used for hybridization hybridization /hy·brid·iza·tion/ (hi?brid-i-za´shun) 1. crossbreeding; the act or process of producing hybrids. 2. molecular hybridization 3. . The probe was tested on an array of Perkinsus sp.-infected, paraffin-embedded tissues (Table 1), including Perkinsus marinus in Crassostrea virginica, P. atlanticus in Ruditapes decussatus, P. olseni in Haliotis laevigata, Perkinsus andrewsi in Macoma balthica, Perkinsus sp. in Vereurupis philippinarum from Japan. Perkinsus chesapeaki in Mya arenaria, Perkinsus mediterraneus n. sp. in Ostrea edulis (Casas et al. in press), Perkinsus sp. in Chama pacificus, and P. qugwadi in Patinopecten yessoensis. Probe specificity was validated by testing tissue sections of the blue crab Callinectes sapidus, which was infected with the parasitic dinoflagellate dinoflagellate Any of numerous one-celled, aquatic organisms that have two dissimilar flagella and characteristics of both plants (algae) and animals (protozoans). Most are microscopic and marine. Hematodinium sp. (Shields 1994), Hematodinium sp.-infected Norway lobster Nephrops norvegicus (Field & Appleton 1995), Haplosporidum nelsoni-infected and Haplosporidum costale-infected C. virginica oysters, and spot prawn prawn: see shrimp. Pandalus platyceros, infected by an undescribed haplosporidian-like protozoan protozoan (prō'təzō`ən), informal term for the unicellular heterotrophs of the kingdom Protista. Protozoans comprise a large, diverse assortment of microscopic or near-microscopic organisms that live as single cells or in simple parasite (Bower & Meyer 2002). Replicate sections of nonspecific nonspecific /non·spe·cif·ic/ (non?spi-sif´ik) 1. not due to any single known cause. 2. not directed against a particular agent, but rather having a general effect. nonspecific 1. ISH assay signal controls of each sample were tested identically, except that they received hybridization buffer without probe during the overnight hybridization step. RESULTS Histologic Evaluation of Infected Clams The prevalence of juvenile clams infected with the presumptive pre·sump·tive adj. 1. Providing a reasonable basis for belief or acceptance. 2. Founded on probability or presumption. pre·sump Perkinsus sp., was 59 of 64 (92%), based on histologic examination. The protozoa were systemically distributed in a variety of organs, most typically in subepithelial areas of the gills, and frequently in the mantle and labial labial /la·bi·al/ (la´be-al) 1. pertaining to a lip or labium. 2. in dental anatomy, pertaining to the tooth surface that faces the lip. la·bi·al adj. palps. Parasites were often associated with tissue hemocytosis (Fig. 1) and occurred as single or multiple trophozoites (Fig. 2). In severe infections, the parasites were more abundantly distributed in the tissues, including the vascular sinuses around the digestive diverticula diverticula /di·ver·tic·u·la/ (di?ver-tik´u-lah) [L.] plural of diverticulum. Diverticula A diverticulum of the colon is a sac or pouch in the colon walls which is usually asymptomatic (without . Broad areas of the subepithelial connective tissues were composed of solid masses of parasite cysts in the most severe infections. In many cases, the parasites were contained within a thin-walled cyst cyst, abnormal sac in the body, filled with a fluid or semisolid and enclosed in a membrane. Cysts can be congenital but are usually acquired, the most common locations being the skin and the ovaries. formed by one to several host cells (Fig. 3). Such encapsulations contained up to 10 protozoan cells and associated hemocytosis. The parasites were often characterized by the presence of an eccentric vacuole (Fig. 1 and 3), characteristic of Perkinsus sp. trophozoites. [FIGURES 1-3 OMITTED] Confirmation of Perkinsus sp. by ISH The genus-Perkinsus SSUrRNA gene probe Perksp700DIG demonstrated strong hybridization to Perkinsus sp. cells in all of the tissue sections, except those of P. qugwadi infecting P. yessoensis (Table 1 and Fig. 4A-I A-I General Audiences (Catholic movie rating) ). No hybridization to parasite cells of other genera was observed. ISH of parasite cells in tissue sections of infected Korean Manila clams with this genus-Perkinsus probe confirmed the genus level affiliation of the parasites in our sample of juvenile Korean Manila clams (Fig. 5). [FIGURES 4-5 OMITTED] DISCUSSION We report the confirmation by ISH assays and histology of Perkinsus sp. infections in Manila clam seed proposed for the introduction into Mexican waters and the subsequent transport to growout sites on the Pacific coast of the United States. This is the first confirmation by a molecular diagnostic probe of Perkinsus sp. infection of Korean Manila clams As a result of these findings, the plan for importation of these clams was rejected by the shellfish producer, and no Korean seed clams were imported to the west coasts of Mexico or the United States. However, the ready availability of such infected seed clams from Korean or Japanese producers requires vigilance to ensure that no such importations take place into areas that are free of the pathogen, such as the west coasts of North and Central America. Reports of lethal Perkinsus sp. infections in European and eastern Asian Manila clams from latitudes as far north as that of northern Oregon, confirm the high likelihood that such infections, if introduced, could persist and be transmitted, with damaging results to both wild and cultured clam stocks along the Pacific coasts of North and Central America. This study demonstrated that infection prevalence in seed clams ranging from 16 to 32 mm SL can be nearly 100% and that high parasite intensities cause significant histologic damage to the organs of infected clams, particularly the gills. Choi and Park (1997) studied five species of Korean clams for infections by Perkinsus sp. using Ray's fluid thioglycollate medium thioglycollate medium one used for culturing anaerobic bacteria. (Ray 1966) and found infected Manila clams along the south coast of Korea. While no infection occurred in clams of <15 mm SL, nearly 100% infection prevalence occurred in clams of >20 mm SL. Park et al. (1999) reported mass mortality of Manila clams along the west and south coasts of Korea over a period of several years, which was associated with Perkinsus sp. infections. They reported 100% infection prevalence in 142 clams from Komsoe Bay on the west coast of Korea with moderately severe mean parasite intensities of 2.87 based on the infection intensity scale of Choi et al. (1989). A negative correlation was found between the intensity of Perkinsus sp. infections and the clam condition index, while clam size was positively correlated with infection intensity. Maeno et al. (1999) reported Perkinsus sp. parasites in Manila clams from an inner bay of the western part of Japan in April 1998, using genus-Perkinsus-specific antibodies. These authors concluded that the parasites were Perkinsus sp. based on a positive reaction with both single and clustered trophozoites. Hamaguchi et al. (1998) have reported the first detection of Perkinsus sp. in Japanese Manila clams. Anecdotal information that we received from the Korean supplier of the seed clams and their Japanese customers indicated that the Manila clam seed had been transported from the Korean source to Japan for at least 20 y with no unusual mortalities or loss of growth reported. This anecdotal report and the multiple reports of the Perkinsus sp. parasite occurring about 1997 or 1998 in Japan and Korea suggest that it could have been a new introduction to the Korean clams, as well as the Japanese clams, at about this time. Manila clams and other bivalve species from Europe reportedly have been infected with Perkinsus sp., as follows: P. atlanticus from the Mediterranean coast of Spain (region of the Ebro Delta, Tarragona, Spain) infected R. philippinarum (Sagrista et al. 1996); Manila clams from the Lagoon of Venice in northeast Italy infected with a Perkinsus sp. (DaRos et al. 1998); and P. atlanticus infected the carpet shell clam (R. decussatus) from European locations (Ordas et al. 2000). Villalba et al. (2000) reported a significant correlation between the SL of R. decussatus and P. atlanticus infection intensity. No clams of <20 mm SL were infected, and the highest seasonal parasite intensities occurred in spring and late summer to early autumn. The relationship of Perkinsus sp. in European waters to the Perkinsus sp. found in Korea and Japan is unknown at this time. Nonetheless, this and other studies cited in this report indicate the presence of this damaging parasite in Korean and Japanese Manila clams, confirmed first in this study by histology and then definitively by the Perkinsus sp.-specific probe presented for the first time in this article. This knowledge can be used to prevent the unintentional introduction of this parasite to west coast of North and Central America. We urge that the science presented in this article be applied by shellfish growers, and by natural resource and conservation managers to prevent such a damaging introduction.
TABLE 1.
ISH assay results with genus-Perkinsus SSUrRNA probe,
Perksp700DIG.
Parasite Host Sample
Perkinsus sp. V. philippinarum 98-SH14-5
Perkinsus sp. V. philippinarum 98051504-2
P. atlanticus R. decussatus 685a
P. olseni H. laevigata ST389-35
P. chesapeaki M. arenaria CHBRMa-14
P. andrewsi M. balthica MB3a2
P. marinus C. virginica 221, 556-15
P. mediterraneus O. edulis 08 and 016
Perkinsus sp. C. pacificus CH02882
P. qugwadi P. yessoensis 6492-A5
Haplosporidium nelsoni C. virginica 201, 239
H. costale C. virginica 196, 774
haplosporidian-like sp. P. platyceros 90-568J
Hematodinium sp. C. sapidus 98-513
Hematodinium sp. N. norvegicus 990427Nnor-1
[+ or -] Probe Sample
Parasite Hybridization Source
Perkinsus sp. + R. A. Elston
Perkinsus sp. + Y. Maeno
P. atlanticus + C. Azevedo
P. olseni + C. L. Goggin
P. chesapeaki + C. Dungan
P. andrewsi + F. G. Kern
P. marinus + K. S. Reece
P. mediterraneus + A. Villalba
Perkinsus sp. + C. L. Goggin
P. qugwadi - S. M. Bower
Haplosporidium nelsoni - E. Burreson
H. costale - E. Burreson
haplosporidian-like sp. - S. M. Bower
Hematodinium sp. - J. D. Shields
Hematodinium sp. - G. Stentiford
Parasite Reference
Perkinsus sp. this article
Perkinsus sp. Maeno et al. 1999
P. atlanticus Azevedo 1989
P. olseni Goggin et al. 1989
P. chesapeaki Dungan et al. 2002
P. andrewsi Coss et al. 2001
P. marinus Mackin et al. 1950
P. mediterraneus Casas et al. in press
Perkinsus sp. Goggin et al. 1989
P. qugwadi Blackbourne et al. 1998
Haplosporidium nelsoni Haskin et al. 1966
H. costale Couch 1967
haplosporidian-like sp. Bower & Meyer 2002
Hematodinium sp. Shields 1994
Hematodinium sp. Field & Appleton 1995
ACKNOWLEDGMENTS N. A. Stokes, K. L. Hudson, K. Apakupakul, and R. M. Hamilton provided expert technical assistance in the performance of ISH assays. Perkinsus sp.-infected mollusc mollusc members of the phylum Mollusca, which comprises about 50,000 species. Includes snails, slugs and the aquatic molluscs—oysters, mussels, clams, cockles, arkshells, scallop, abalone, cuttlefish, squid. histologic samples were generously provided by C. Azevedo, S. M. Bower, E. M. Burreson, C. L. Goggin, F. G. Kern, and Y. Maeno. Parasitic dinoflagellate-infected crustacean crustacean (krŭstā`shən), primarily aquatic arthropod of the subphylum Crustacea. Most of the 44,000 crustacean species are marine, but there are many freshwater forms. tissue samples were provided by J. D. Shields and G. D. Stentiford. This work was supported in part by National Oceanic and Atmospheric Administration Noun 1. National Oceanic and Atmospheric Administration - an agency in the Department of Commerce that maps the oceans and conserves their living resources; predicts changes to the earth's environment; provides weather reports and forecasts floods and hurricanes and (NOAA NOAA abbr. National Oceanic and Atmospheric Administration Noun 1. NOAA - an agency in the Department of Commerce that maps the oceans and conserves their living resources; predicts changes to the earth's environment; ) Sea Grant funding of project NA86RG0037 to CFD CFD - Computational Fluid Dynamics . This work is also a result of research sponsored in part by NOAA Office of Sea Grant, U.S. Department of Commerce, under grant No. NA96RG0025 to the Virginia Graduate Marine Science Consortium and the Virginia Sea Grant College sea grant college n. A college or university that receives government grants for oceanographic research. Program, and under grant No. NA016RG2207 to the Maryland Graduate Marine Science Consortium and the Maryland Sea Grant College Program. The U.S. Government is authorized to produce and distribute reprints for governmental purposes, notwithstanding any copyright notation that may appear hereon here·on adv. On this; hereupon. . VIMS VIMS Virginia Institute of Marine Science VIMS Visible and Infrared Mapping Spectrometer VIMS Visual Information Management System(s) VIMS Vehicle Information Management System VIMS Virtual Incident Management System contribution #2575. LITERATURE CITED American Fisheries Society. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd ed. American Fisheries Society Special Publication 26. Bethesda, MD. Azevedo, C. 1989. Fine structure of Perkinsus atlanticus n. sp. (Apicomplexa, Perkinsea) parasite of the clam Ruditapes decussatus from Portugal. J. Parasitol. 75:627-635. Blackbourne, J., S. M. Bower & G. R. Meyer. 1998. Perkinsus qugwadi sp. nov. (incertae sedis), a pathogenic protozoan parasite of Japanese scallops, Patinopecten yessoensis, cultured in British Colombia, Canada. Can. J. Zool. 76:942-953. Bower, S. M. & G. R. Meyer. 2002. Morphology and ultrastructure ultrastructure /ul·tra·struc·ture/ (-struk?chur) the structure beyond the resolution power of the light microscope, i.e., visible only under the ultramicroscope and electron microscope. of a protistan pro·tist n. Any of the eukaryotic, unicellular organisms of the former kingdom Protista, which includes protozoans, slime molds, and certain algae. pathogen in the haemolymph of shrimp (Pandalus spp.) in the northeastern Pacific Ocean. Can. J. Zool. 80:1055-1068. Casas, S. M., A. Grau, K. S. Reece, K. Apakupakul, C. Azevedo & A. Villalba. 2003. Perkinsus mediterraneus n. sp. a protistan parasite of the European flat oyster Ostrea edulis (L.) from the coast of Balearic Islands, Mediterranean Sea. Dis. Aquat. Org. in press. Choi, K. S. & K. I. Park. 1997. Report on the occurrence of Perkinsus sp.in the Manila clams, Ruditapes philippinarum in Korea. (Korean) J. Aquaculture 10:227-237. Choi, K.-S., E. A. Wilson, D. H. Lewis, E. N. Powell & S. M. Ray. 1989. The energetic cast of Perkinsus marinus parasitism parasitism: see parasite. parasitism Relationship between two species in which one benefits at the expense of the other. Ectoparasites live on the body surface of the host; endoparasites live in their hosts' organs, tissues, or cells and often rely in oysters: quantification of the thioglycellate method. J. Shellfish Res. 8:125-131. Coss, C. A., J. A. F. Robledo & G. R. Vasta. 2001. Description of Perkinsus andrewsi n. sp. isolated from the Baltic clam (Macoma balthica) by characterization of the ribosomal RNA ribosomal RNA n. See rRNA. ribosomal RNA (rī´bōsō´m locus, and development of a species-specific PCR-based diagnostic assay. J. Eukaryot. Microbiol. 48:52-61. Couch, J. A. 1967. Concurrent haplosporidian infections of the oyster, Crassostrea virginica (Gmelin). J. Parasitol. 53:248-253. DaRos, L., M. G. Marin, N. Nesto & S. E. Ford. 1998. Preliminary results on a field study on some stress-related parameters in Tapes philippinarum naturally infected by the protozoan Perkinsus sp. Mar. Env. Res. 46:249-252. Dungan, C. F., R. M. Hamilton, K. L. Hudson, C. B. McCollough & K. S. Reece. 2002. Two epizootic ep·i·zo·ot·ic adj. Affecting a large number of animals at the same time within a particular region or geographic area. Used of a disease. ep diseases in Chesapeake Bay commercial clams, Mya arenaria and Tagelus plebeius. Dis. Aquat. Org. 50:67-78. Field, R. H. & P. L. Appleton. 1995. A Hematodinium-like dinoflagellate infection of the Norway lobster Nephrops norvegicus: observations on pathology and progression of infection. Dis. Aquat. Org. 22:115-128. Goggin, C. L., K. B. Sewell & R. J. G. Lester. 1989. Cross-infection experiments with Australian Perkinsus species. Dis. Aquat. Org. 7:55-59. Hamaguchi, M., N. Suzuki, H. Usuki & H. Ishioka. 1998. Perkinsus protozoan infection in short-necked clam Tapes (= Ruditapes) philippinarum in Japan. Fish Pathol. 33:473-480. Haskin, H. H., L. A. Stauber & J. G. Mackin. 1966. Minchinia nelsoni n. sp. (Haplosporida, Haplosporidiidae): causative agent of the Delaware Bay oyster epizootic. Science 153:1414-1416. Liang, Y.-B., X.-C, Zhang, L.-J. Wang, B. Yang, Y. Zhang & C.-L. Cai. 2001. Prevalence of Perkinsus sp. in the Manila clam Ruditapes philippinarum along northern coast of Yellow Sea in China. Oceanol. et Limnol. Sinica 32:502-511. Mackin, J. G., M. Owen & A, Collier, 1950. Preliminary note on the occurrence of a new protistan parasite, Dermocystidium marinum n. sp. in Crassostrea virginica (Gmelin). Science 111:328-329. Maeno, Y., T. Yoshinaga & K. Nakajima. 1999. Occurrence of Perkinsus species (Protozoa, Apicomplexa) from Manila clam Tapes philippinarum in Japan. Fish Pathol. 34:127-131. Murrell, A., S. N. Kleeman, S. C. Barker & R. J. G. Lester. 2002. Synonymy syn·on·y·my n. pl. syn·on·y·mies 1. The quality of being synonymous; equivalence of meaning. 2. Study and classification of synonyms. 3. A list, book, or system of synonyms. 4. of Perkinsus olseni Lester & Davis, 1981 and Perkinsus atlanticus Azevedo, 1989 and an update on the phylogenetic phy·lo·ge·net·ic adj. 1. Of or relating to phylogeny or phylogenetics. 2. Relating to or based on evolutionary development or history. position of the genus. Perkinsus. Bull Eur. Assoc. Fish Pathol. 22:258-265. Navas, J. I., M. C. Castillo, P. Vera & M. Ruiz-Rico. 1992. Principal parasites observed in clams, Ruditapes decussates (L.), Ruditapes philippinarum (Adams et Reeve), Venerupis pullastra (Montagu), and Venerupis aureus The aureus (pl. aurei) was a gold coin of ancient Rome valued at 25 silver denarii. The aureus was regularly issued from the 1st century BC to the beginning of the 4th century AD, when it was replaced by the solidus. (Gmelin), from the Huelva coast (S.W. Spain). Aquaculture 107:193-199. Ordas. M., A. Ordas, C. Beloso & A. Figueras. 2000. Immune parameters in carpet shell clams infected with Perkinsus atlanticus. Fish Shellfish Immunol. 10:597-609. Pacific Coast Shellfish Growers Association. 2003. West Coast shellfish production. Olympia, WA: Pacific Coast Shellfish Growers Association. Available at: www.pcsga.org. Park, K. I., K. S. Choi & J. W. Choi. 1999. Epizootiology of Perkinsus sp. found in the Manila clam, Ruditapes philippinarum in Komsoe Bay, Korea. J. Korean Fish. Soc. 32:303-309. Pacific Shellfish Institute. 2001. Manila Clam Mortality and Health Evaluation. Final report to Saltonstall-Kennedy Program, National Marine Fisheries Service The U.S. National Marine Fisheries Service (NMFS) is a United States federal agency. A division of the National Oceanic and Atmospheric Administration (NOAA) and the Department of Commerce, NMFS is responsible for the stewardship and management of the nation's living marine , U.S. Department of Commerce on Grant No. Grant Number: NA96FD0194. Olympia, WA: Pacific Shellfish Institute. Ray, S. M. 1966. A review of the culture method of detecting Dermocystidium marinum, with suggested modifications and precautions. Proc. Natl. Shellfish Assn. 54:55-69. Sagrista, E., M. Durfort & C. Azevedo. 1996. Ultrastructural data on the life cycle of the parasite, Perkinsus atlanticus (Apicomplexa), on the clam. Ruditapes philippinarum, in the Mediterranean. Sci. Mar. Barc. 60:283-288. Shaw, B. L. & H. I. Battle. 1957. The gross and microscopic anatomy microscopic anatomy n. The study of the structure of cells, tissues, and organs of the body as seen with a microscope. of the digestive tract digestive tract n. See alimentary canal. Digestive tract The organs that perform digestion, or changing of food into a form that can be absorbed by the body. of the oyster, Crassostrea virginica (Gmelin). Can. J. Zool. 35:325-347. Shields, J. D. 1994. The parasitic dinoflagellates of marine crustaceans. Ann. Rev. Fish. Dis. 4:241-271. Stokes, N. A. & E. M. Burreson. 1995. A sensitive and specific DNA probe for the oyster pathogen Haplosporidium nelsoni. J. Eukaryot. Microbiol. 42:350-357. Stokes, N. A. & E. M. Burreson. 2001. Differential diagnosis differential diagnosis n. Determination of which one of two or more diseases with similar symptoms is the one from which the patient is suffering. Also called differentiation. of mixed Haplosporidium costale and Haplosporidium nelsoni infections in the eastern oyster, Crassostrea virginica, using DNA probes. J. Shellfish Res. 20:207-213. Villalba, A., S. M. Casas, M. J. Carballal & C. Lopez. 2000. Effects of perkinsiosis on the clam Ruditapes decussatus industry of Galicia (NW Spain). J. Shellfish Res. 19:649. RALPH A. ELSTON, (1) * CHRISTOPHER F. DUNGAN, (2) THEODORE R. MEYERS (3) AND KIMBERLY S. REECE (4) (1) AquaTechnics, PO Box 687, Carlsborg, Washington 98324; (2) Maryland Department of Natural Resources The Maryland Department of Natural Resources is a Government agency in the state of Maryland charged with maintaining natural resources such as state parks, public lands, state forests, and recreation areas. , Cooperative Oxford Laboratory, 904 S. Morris Street, Oxford, Maryland 21654; (3) Alaska Department of Fish and Game, PO Box 25526, Juneau, Alaska 99802: (4) Virginia Institute of Marine Science, PO Box 1346, College of William and Mary Noun 1. William and Mary - joint monarchs of England; William III and Mary II , Gloucester Point, Virginia Gloucester Point is a census-designated place (CDP) in Gloucester County, Virginia, United States. The population was 9,429 at the 2000 census. Geography Gloucester Point is located at (37.269907, -76. 23062 * Corresponding author. E-mail: aquatech@olypen.com |
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