J. Parisitol. 88(5), 2002, pp. 856-863

American Society of Parisitologists 2002

HISTOLOGICAL ANALYSIS OF TREMATODES IN DREISSENA POLYMORPHA:

THEIR LOCATION, PATHOGENICITY, AND DISTINGUISHING MORPHOLOGICAL CHARACTERISTICS

Franck Laruelle, Daniel P. Molloy¹, and Vitali A. Roitmant²

CEDRE. Rue Alain Colas, BP 20413-29604 Brest Cedex. France email: dmolloy@mail,nysed,gov

ABSTRAC'T: Four families of trematodes were observed in histological sections during a 1992-1997investigation of the parasites of zebra mussels, Dreissena polymorpha. These included Aspidogastridae. i.e., Aspidogaster, Echinostomatidae, Bucephalidae, i.e., Bucephalus polymorphus and Gorgoderidae, i.e., Phyllodistomum folium. This article describes the precise location of these trematodes in the tissues of D. polymorpha, provides graphic evidence of their effect on the organs they inhabit, and highlights the distinguishing morphological characteristics. Evidence of defense reaction of host to trematodes infection, i.e. encapsulation of Aspidogaster and necrezation of B. polymorphus is also presented and is the first such report for zebra mussels. The histological photomicrographs included represent the first comprehensive series published on trematodes infection of zebra mussels. These images, in conjunction with morphological descriptions presented, should assist researches in identifying the 4 major trematodes taxa that they are likely to encounter in the tissue sections of zebra mussels.

Received 9 August 2000; revised 11 December 2001; accepted 9 April 2002.

¹To whom correspondence should be addressed. Division of Research and Collections. New York State Museum. The State Education Department, Albany. New York 12230.

² Deceased. Institute of Parasitology. Russian Academy of Sciences. Leninsky Prospect 33. Moscow 117071. Russia.