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

FLORENCIA CREMONTE; PABLO BALSEIRO; ANTONIO FIGUERAS

DISEASES OF AQUATIC ORGANISMS

INTER-RESEARCH

Año: 2005 vol. 64 p. 85 - 90

0177-5103

A study was conducted into the health status of natural populations of the venerid clamPitar  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.