Issue |
Parasite
Volume 5, Number 3, September 1998
|
|
---|---|---|
Page(s) | 263 - 271 | |
DOI | https://doi.org/10.1051/parasite/1998053263 | |
Published online | 19 September 2014 |
Mémoire
Histopathological alterations associated with Perkinsus spp. infection in the softshell clam Mya arenaria
Modifications histopathologiques associées à l'infection de la palourde à coquille lisse, Mya arenaria, par Perkinsus spp.
1
National Marine Fisheries Service, NOAA, Cooperative Oxford Laboratory, 904 South Morris St., Oxford, Maryland 21654-9724.
2
Virginia Institute of Marine Science, School of Marine Science, The College of William and Mary, Gloucester Point, Virginia 23062.
* Correspondence : Shawn McLauglin. Tel. : 410/226-5193 — Fax : 410/226-5925. Disclaimer : Reference to trade names does not imply endorsement by the National Marine Fisheries Service.
Received:
23
March
1998
Accepted:
25
June
1998
Softshell clams (Mya arenaria) collected from the Chester River in the upper Chesapeake Bay showed the presence of Perkinsus spp. in ~ 1 2 % (28/240) of clams examined. The infection seems to run a mild course with the host prevailing in encapsulating invading parasites. The gills appear to be the major site of infection; however, the parasite was also found in the digestive gland, gonads, and kidneys and occasionally in the tissue and sinuses of adductor muscles. Typically, clusters of protozoal cells were embedded in an amorphous PAS-positive substrate and were surrounded by one or more layers of granulocytes. In heavy infections, both free and encapsulated Perkinsus spp. cells were observed in affected tissue forming aggregations of different sizes. Within the tissues of M. arenaria, the parasite propagated by schizogony. The presence of large encapsulations in vital organs such as the gills and gonads may adversely affect growth and fertility of affected clams.
Résumé
La présence de Perkinsus spp. a été constatée dans environ 12 % (28/240) des palourdes (Mya arenaria) récoltées dans le fleuve Chester, dans la partie haute de la Baie de Chesapeake. L'infection semble d'évolution bénigne chez l'hôte, avec encapsulation des parasites. L'infection parait essentiellement localisée aux branchies; cependant, le parasite a également été observé dans les glandes digestives, les gonades et le rein, et occasionnellement dans le tissu et les sinus des muscles adducteurs. Des grappes de cellules protozoaires sont typiquement incluses dans un substrat amorphe PAS positif et entourées d'une ou plusieurs couches de granulocytes. Dans les infections importantes, on observe à la fois des cellules de Perkinsus spp.encapsulées et des cellules libres dans le tissu atteint, formant des aggrégats de différentes tailles. Le parasite se propage dans les tissus de M. arenaria par schizogonie. La présence d'encapsulations de grande taille dans des organes vitaux comme les branchies et les gonades est susceptible d'affecter la croissance et la fertilité des palourdes atteintes.
Key words: Softshell clam / Perkinsus spp. / histopathology / gills / encapsulation
Mots clés : palourde à coquille lisse / Perkinsus spp. / histopathologie / branchies / encapsulation
© PRINCEPS Editions, Paris, 1998, transferred to Société Française de Parasitologie
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