Although the effect exerted on fish by fluke cercariae developing in fish as intermediate hosts is fairly well known, cercariae of flukes requiring intermediate hosts other than fish occur in fish ponds in much higher numbers. To study the effect of these latter cercariae on fish fry, a few days old common carp fry (Cyprinus carpio) were exposed to cohorts of xiphidiocercariae or echinocercariae shed by one or two snails acting as intermediate hosts. The observed pathogenicity of these cercariae was compared to the well-known pathogenic effect ofDiplostomumcercariae. AlthoughDiplostomumcercariae proved to be the most pathogenic, occasionally also the other two types of cercariae could kill the common carp fry by invading their body. Xiphidiocercariae ingested by the fish penetrated the intestinal wall and developed into metacercariae within the body of the fry. They could also get into the musculature through the skin. The much larger echinocercariae invaded the gill cavity where they became encapsulated, thus hampering gill function and leading to fish mortality due to oxygen deficiency.Diplostomumcercariae were more pathogenic than the cercariae of the other two flukes in that they were shed by the intermediate host in very large numbers. Although much less xiphidiocercariae and echinocercariae emerged from the intermediate host snails thanDiplostomumcercariae, the former could kill the fish fry already in lower numbers. These findings prove that fluke cercariae nonspecific to fish may exert pathogenic effects on fish, and presumably contribute to the early mortality of young fry placed out into fish ponds.
Authors:L. Majoros, G. Kardos, I. Pócsi, and B. Szabó
Data of Candida albicans and non-albicans Candida species isolated during the 1997-2000 period in the Medical and Health Science Center of the University of Debrecen are analysed. The number of yeast isolates increased from 408 to 1213 per year during this period. Dominance of C. albicans has been persistent, but a slight increase of C. glabrata and C. krusei could be observed. Distribution of different Candida species isolated from 16 body sites indicates that C. albicans seems to be still the most aggressive Candida species. Investigation of 244 urinary Candida isolates (parallel with bacterial cultures) suggests that tha aetiological role of Candida species in the pathogenesis of urinary tract infections can be hypothesized if colony forming unit (CFU) number of yeasts is higher than 104/ml and bacteria are present in low CFU number or are absent. Antifungal susceptibility testing of C. albicans, C. glabrata, C. tropicalis and C. krusei against Flucytosine, Amphotericin-B, Miconazole, Ketoconazole and Fluconazole suggests that Amphotericin-B is still the most effective antifungal agent. Finally, the problems in judging the aetiological role of isolated Candida species in the pathogenesis of different types of diseases are critically discussed.
Authors:K. Heckner, G. Majoros, A. Kraft, and R. Landsberg
The lowering of the photocorrosion ofn-GaP in 1M KOH in the presence of several redox systems was investigated using neutron activation analysis. After thermal neutron irradiation of GaP and annihilation of irradiation induced defects by annealing processes the photodissolution was investigated by measuring the activity of the corresponding electrolyte solutions. The dependence of the stabilization of the photoelectrode on concentration and redox potential of the reduced form of the redox couples I–, Fe (CN)
was measured. It was found that the stabilization is growing with growing concentration and lowering of the redox potential of the corresponding redox couple.