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    Sheet no 52 Sheet no 52 Document Transcript

    • ICES Identification Leaflets for Diseases and Parasites of Fish and Shellfish Prepared under the guidance of the ICES Working Group on Pathology and Diseases of Marine OrganismsFiches dIdenMcation des Maladies et Parasites des Poissons, Crustacks et MollusquesPrCparCes sous les auspices du Groupe de Travail CIEM sur la Pathologie et Maladies des Organismes marins LEAFLET NO. 52 Gaffkemia, a bacterial disease of lobsters: Genus Homarus FICHE No 52 Gaffkkmie, maladie bactkrienne gknkraliske du homard JAMES E. STEWART and L. J. MARKS Department of Fisheries and Oceans Bedford Institute of Oceanography PO Box 1006, Dartmouth, Nova Scotia, Canada B2Y 4A2 Edited by / ~ d i t k e par s GILLES OLIVIER during his association with / pendant son association avec Fisheries and Oceans Canada Halifax, Nova Scotia, Canada B3J 2S7 INTERNATIONAL COUNCIL FOR THE EXPLORATION OF THE SEA CONSEIL INTERNATIONAL POUR LEXPLORATION DE LA MER P a l ~ g a d e 4 , DK-1261 Copenhagen K, Denmark / Copenhague K, Danemark 2 1999 ISSN 0109-2510
    • Figure 1. Hemolymph smear from an infected lobster showing typical A. viridans (var.) homari morphology, particularly the forma-tion of tetrads; x ca. 1600 (a) Gram stain, (b) IFAT.Figure 1. Frottis de lhemolymphe dun homard infect6 montrant la morphologie typique dA. viridans (var. homari), particuliere-ment la formation de tetrades. (a) coloration de Gram, (b) immunofluorescence indirecte.Gaffkemia, a bacterial disease of lobsters: genus Gaffkkmie, maladie bactkrienne gknkraliske duHomarus homardHost species EspPce h8teLobsters of the genus Homarus (Homarus americanus Les homards du genre Homarus (Homarus americanusand Homarus vulgaris or gammarus) et Homarus vulgaris od garnmarus) Nom de la maladieDisease name Gaffktmie, maladie du sang ou "pink tail"Gaffkemia, less commonly blood disease or pink tail ~tiolo~ieEtiology Infection bactkrienne gknCralisCe par le Gram-positifSystemic infection by the Gram-positive bacterium Aerococcus viridans var. homari precedemment nommeAerococcus viridans (var.) homari, previously named Gaffi~aGafJya homari Conditions de milieu Inconnues. Un site dentrke, suite a une perforation deAssociated environmental conditions lenveloppe de chitine permettant ainsi lacces du germeNo specific conditions required. A portal of entry d lhtmolymphe, est essentiel puisque cette bacttrie negained by breaching the continuous chitinous sheath posskde pas de pouvoir envahisseur. Le temps requisthereby permitting access to the hemolymph of the host entre linfection et la mort est directement relie a laanimal is essential, since the pathogen has no invasive temperature de leau et ce, a partir de 3°C. Densiteproperties. Time between infection and death is elevee, diminution de la teneur en oxygine, variation decontrolled by temperature at 3°C and above. Crowding, saliniti. et un environnement dtfavorable sont toutes desreduced oxygen, salinity changes, and generally poor causes favorisantes qui augmentent la chance de creerenvironments enhance wounding and reduction in the des sites dentree et reduisent la resistance naturelle deshost animals condition and thus aid the spread of the animaux, constquemment elles aident a la transmissioninfection and reduce the time between infection and de la maladie et rkduisent le temps entre linfection et ladeath. mort.
    • Geographical distribution Distribution gkographiqueHas been detected among wild lobsters throughout the Signale dans les populations de homards vivant enlobster range in North America and in Europe, specifically milieu naturel, aussi bien en Amerique du Nord quenin France and the United Kingdom. Has occurred among Europe, plus particulierement en France et en Grandelive stored lobsters on both sides of the Atlantic Ocean. Bretagne. Des Cpizooties ont etk signalees chez les homards gardes en captivite en Amerique du Nord et enSignificance Europe.Lobsters infected with even a few cells (ca. 5 bacterial cells/kg body weight) of a virulent strain of A. viridans (var.) Importancehomari invariably die. On occasion, the disease undoubt- Les homards meurent suite une infection experimen-edly has an important but undetermined impact on wild tale de seulement quelques cellules bacteriennes (cinqstocks of lobsters. It can be highly damaging to live stored bacterieslkg poids vif) dune souche virulente dA.lobsters, periodically causing severe losses. viridans var. homari. Cette maladie aurait probablement, i Ioccasion, un impact important sur les populations deControl homard vivant en milieu naturel mais cet impact resteNone among wild stocks. Reduced temperatures, encore indetermine. De fortes mortalites ont deja eteprotection against wounding, and constant culling of observees chez les homards gardes en captivite.weak lobsters reduces the impact among lobsters storedlive. Uninfected animals protected against wounding, by Prophylaxie et traitementbeing housed in units in which physical separation is Non realisables sur les homards vivant en milieupossible, are proof against transmission of the disease. naturel. Chez les homards maintenus en captivite, lesThe pathogen in the early stages of the infection can be facteurs suivants peuvent minimiser Iimportance de lacontrolled by antibiotics. Disinfection of storage facil- maladie: baisse de temperature, protection des animauxities following an epizootic is essential if future contre tout facteur pouvant les blesser ainsi que Ielimi-outbreaks are to be restricted or controlled. Vaccination nation constante des animaux faibles ou malades. Leswith an immunogen prepared from virulent strains of A. animaux sains ne sont pas infectes sils sont protegesviridans (var.) homari has provided protection against contre toute blessure par leur isolement dans des casesinfection in laboratory and field trials. individuelles, ou il ny a aucun contact physique, demontrant ainsi le faible potentiel de transmission duGross clinical signs pathogene. Au debut de linfection, le pathogene peutNone apparent in the early to mid-stages of the infection. 6tre contr6le par ladministration dantibiotiques. LaIn later stages. the lobsters become weak and assume a - , desinfection des cages, ou les animaux sont gardes, estspread-eagled position, or, through overbalancing, topple essentielle apres une epizootie pour Cviter de nouvelleshelplessly on to their backs shortly before death. When infections. Un vaccin &labor& partir dune souche viru- alobsters in an advanced stage of the infection are lente Aerococcus vividans var. homari protege contre laremoved from the water, they die within 20 to 30 minutes. maladie suite a des experiences en laboratoire et des essais de terrain.HistopathologyIn deliberately infected lobsters (H. americanus), hemocyte Signes cliniques macroscopiquesaggregations were observed in hemal spaces, throughout Aucun signe visible au debut et au stade intermediairethe tissues, increasing in number and size with time. Early de linfection. Dans les stades plus avances, les homardsphagocytosis of bacteria by fixed phagocytes in hemal sont affaiblis et ont tendance a se replier sur eux-m&messpaces of the hepatopancreas was followed by premature ou montrent des troubles dequilibre, dans certains cas,release of differentiating hemocytes, resulting in popula- les homards se retournent sur le dos peu de temps avanttions composed mainly of large stem cells. By the midpoint de mourir. Lorsque les homards sev2rement infecttsof the infection the phagocytes lysed and the freed bacteria sont retires de Ieau: ils meurent rapidement (20-30reached levels of 1 x lo8 to 1 x 109/gin the hemolymph min).and hepatopancreas. Hemolymph clotting is impaired,thereby prolonging the time for clot formation and Histopathologieresulting eventually in elimination of clotting. All other Lors dinfections experimentales du homard (H. ameri-tissues appear normal and unaffected. canus) on observe des amas dhemocytes dans lhemo- lymphe et dans les divers tissus, leur nombre augmenteComments et les amas sintensifient plus la maladie progresse. LaDiagnosis in the late stages can be accomplished by phagocytose initiale des batteries par les macrophagesdirect Gram stain of hemolymph smears (Fig. I), co- de 1hepatopancrt.a~ suivie dun relachement prima- estagglutination, or by an indirect fluorescent antibody ture dhemocytes difftrencies ce qui laisse une popula-
    • technique (IFAT), In the early stages, the infection can tion dhemocytes majoritairement composee de largesbe detected in cultures grown from hemolymph by cellules souches. Au stade intermediaire de linfection, laapplication of IFAT, co-agglutination, or by examina- lyse des phagocytes entrafne la liberation des bacteriestion of cultured bacteria. The typical appearance dont le nombre peut atteindre de 1 x lo8 a 1 x 109/gconsists of Gram-positive cocci in tetrad formation. dans lhemolymphe et 1ht.patopancrt.a~.Le systkme deThese bacteria are catalase-negative and exhibit beta- coagulation est affectee lors de linfection, en premierhemolysis on sheep blood agar. It has been determined lieu la coagulation est plus lente jusqua sa disparitionthat there is no toxin involved; death can result from totale. Tous les autres organes ont toutefois une appar-hemorrhaging following wounding in the late infection ence normale.stages or, failing that, through depletion of reservesresulting in massive dysfunction of the hepatopancreas. Remarques Le diagnostic, dans le dernier stade de linfection, estKey references effectuk par des techniques bactt5riologiques telles que laRbfbrences bibliographiques coloration de Gram dun frottis dhemolymphe (Fig. I),Johnson, P. T., Stewart, J. E., and Arie, B. 1981. le test de co-agglutination ou encore par immunufluor- Histopathology of Aevococcus vividans var. homavi escence indirecte. Au debut de linfection, il est possible infection (Gaffkemia) in the lobster, Homarus amevi- de deceler la presence de bacteries par la culture de lhi- canus, and a comparison with histological reactions molymphe. Les frottis de ces cultures montrent typique- to a Gram-negative species, Pseudoinonas pevolens. J. ment la presence de coques Gram-positif en formation Invertebr. Pathol., 38: 127-148. de tktrade. Ces bacttries sont negatives pour le test de laKeith, I. R., Paterson, W. D., Airdrie, D., and Boston, catalase et produisent une htmolyse beta sur gklose L. D. 1992. Defence mechanisms of the American contenant des erythrocytes de mouton. I1 a etC lobster (Homavus americanus): vaccination provided demontrk quaucune toxine nest impliquee dans la protection against gaffkemia infections in laboratory pathologie. Lors des stades avances de linfection, la and field trials. Fish and Shellfish Immunol., 2: 109-1 19. mort des homards est attribuke a des hemorragies asso-Marks, L. J., Stewart, J. E., and Histein, T. 1992. Evalua- ciees aux blessures ou au dysfonctionnement de lhkpa- tion of an indirect fluorescent antibody technique for topancreas suite a lepuisement des reserves. detection of Aevococcus vividans (var.) homavi, pathogen of homarid lobsters. Dis. aquat. Org., 13: Key laboratories 133-138. Laboratoires de rbferenceSaxegaard, F., and Histein, T. 1978. Identification of Department of Fisheries and Oceans, Bedford Institute Aevococcus vividans by means of co-agglutination. of Oceanography, PO Box 1006, Dartmouth, Nova Acta vet. Scand., 19: 604606. Scotia, Canada B2Y 4A2Snieszko, S. F., and Taylor, C. C. 1947. A bacterial disease of the lobster (Homarus americanus). Science, 105: 500. This series is edited by / Cette skrie sera editee par:Stewart, J. E., and Arie, B. 1973. Depletion of glycogen and adenosine triphosphate as major factors in the Dr Sharon E. McGladdery death of lobsters (Homavus amevicanus) infected with Fisheries and Oceans Canada Gaffkya homavi. Can. J. Microbiol., 19: 1103-1 110. Gulf Fisheries CentreStewart, J. E., and Arie, B. 1974. Effectiveness of vanco- PO Box 5030 mycin against gaffkemia, the bacterial disease of Moncton, N.B., Canada E l C 9B6 (ElC 5K4) lobsters (genus Homavus). J. Fish. Res. Bd Can., 31: 1873-1879.Stewart, J. E., Arie, B., Zwicker, B. M., and Dingle, J. R. 1969. Gaffkemia, a bacterial disease of the lobster, Homavus anzericanus: effects of the pathogen on the physiology of the host. Can. J. Microbiol., 15: 925-932.Stewart, J. E., Cornick, J. W., Spears, D. I., and McLeese D. W. 1966. Incidence of Gaffkya homavi in natural lobster (Homavus amevicanus) populations of the Atlantic Region of Canada. J. Fish. Res. Bd Can., 23: 1325-1330.Stewart, J. E., Dockrill, A,, and Cornick, J. W. 1969. Effec- tiveness of the integument and gastric fluid as barriers against transmission of GafJkya lzomavi to the lobster Homarus americanus. J. Fish. Res. Bd Can. 26: 1-14.