DAO 64:85-90 (2005)  -  doi:10.3354/dao064085

Occurrence of Perkinsus olseni (Protozoa: Apicomplexa) and other parasites in the venerid commercial clam Pitar rostrata from Uruguay, southwestern Atlantic coast

Florencia Cremonte1,*, Pablo Balseiro2, Antonio Figueras2

1Centro Nacional Patagónico (CONICET), Boulevard Brown s/nº, 9120 Puerto Madryn, Chubut, Argentina
2Instituto de Investigaciones Marinas (CSIC), Eduardo Cabello 6, 36208 Vigo, Spain

ABSTRACT: A study was conducted into the health status of natural populations of the venerid clam Pitar rostrata from Uruguay. Perkinsus sp. was detected in 22% of the clams. Severe hemocytic infiltration was detected in the tissues parasitized by this protozoan parasite. The sequencing of the ITS-5.8S gene cluster of the parasite confirmed that it belonged to the Perkinsus olseni species. Rickettsia or Chlamidia-like organisms were also found, with a prevalence of 11%, although without apparent host reaction; an unidentified species of Coccidia was found in the nephridia of 78% of the clams, with the intensity of infection ranging from moderate to high. A gregarine, Nematopsis-like organism was observed mainly in the epithelial cells of the intestine, without host response and with a prevalence of 56%. Of the metazoan parasites, trematodes were found in 11% of the individuals analyzed.

KEY WORDS: Perkinsus olseni · Pathology · Pitar rostrata · Venerid clam · Southwestern Atlantic coast

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