LONGEVITY AND EFFECTS OF TEMPERATURE ON THE VIABILITY AND POLAR-TUBE EXTRUSION OF SPORES OF GLUGEA-STEPHANI, A MICROSPORIDIAN PARASITE OF COMMERCIAL FLATFISH

Food contamination with respect to microsporidiosis in humans (associa ted with acquired immunodeficiency syndrome) and in marine fish farmin g deserves particular attention. For the first time, a study on the lo ngevity and resistance to both heat and freezing of the spores of a ve rtebrate microsporidian, Glugea stephani, parasitizing a commercial fl atfish was carried out. As judged on the basis of determinations of th e extrusion rate, the resistance of the spores to temperature stress w as remarkable. The extrusion rate, which can be directly related to in fectivity, was always lower than the viability (membrane integrity). I t should be pointed out that neither heat (60 degrees C for 30 min) no r freezing (-19 degrees C for 24 h) caused a complete reduction in the extrusion rate or viability. Consequently, the ingestion of poorly co oked or raw fish (even if previously frozen) represents a danger for a quaculture and, probably, for immunodepressed patients.