Felsmann MZ, Michalski MM, Felsmann M, Sokół R, Szarek J, Strzyżewska-Worotyńska E. Invasive forms of canine endoparasites as a potential threat to public health -A review and own studies. Ann Agric Environ Med. 2017; 24(2): 245-249. doi: 10.5604/12321966.1235019 AbstractDogs serve as the vectors of serious zoonotic parasitic diseases. In the month of May 2012 -2014, 339 dog faeces samples from seven public sites in Chełmno, a town in northern Poland, were collected and examined to determine the gastrointestinal parasite fauna of dogs. Each faecal sample was dissected with a needle, checked for tapeworm segments and examined for parasite eggs and oocysts using the flotation and decantation method and a modified Baermann technique. Differences were observed in the degree of parasite species occurrence. The most dominant were Toxocara canis and Ancylostomatidae. The detected species included: T. canis and Toxascaris leonina eggs (23.4% and 10.2%, respectively), as well as eggs from the Ancylostomatidae family (16.2%), Trichuris vulpis eggs (6.6%), Taenia type eggs (4.6%), Dipylidium caninum (5.2%) and Cystoisospora (Isospora) spp. oocysts (10.9%).

We investigated environmental impacts on rainbow trout (Oncorhynchus mykiss) reared at fish farms with either extensive technology, in a flow-through system (FTS, n = 3), or intensive technology, in a recirculating aquaculture system (RAS, n = 3). All fish were fed the same rations. Fish were caught in spring and autumn (body mass, 501–750 g) from these six farms. We performed macroscopic (intact fish) and microscopic (gills stained with haematoxylin/eosin) examinations. Lesions were categorised based on the type and location of structural abnormalities. The histopathological index (HAI) was calculated, and each lesion was scored. Fish reared in FTS or RAS were compared for the prevalence of morphological lesions. Gill epithelial hypertrophy and hyperplasia comprised 73% (RAS) to 79% (FTS) of all morphological abnormalities. In spring and autumn, lesions comprised, respectively, 11 and 18% (FTS) and 16 and 10% (RAS) mucous and chloride cell abnormalities and 8 and 4% (FTS) and 10 and 3% (RAS) blood vessel abnormalities. Diffuse, irreversible gill lesions were observed sporadically in all fish. Gill epithelium received the most exposure to environmental pathogens. HAIs indicated that normal gill architecture and minor lesions predominated in all fish. However, among trout caught in spring, moderate and extensive changes in gills occurred more commonly with RAS (34%) than with FTS (17%). Trout caught in autumn displayed no great differences. These results indicated that FTS prepared fish better than RAS for wintering. Moreover, we showed that gills were an excellent biomarker for analysing the impact of extensive and intensive production environments on rainbow trout.

The most popular rainbow trout (Oncorhynchus mykiss, Walbaum 1792) production technologies include both an extensive method with the flow through system (FTS) and an intensive method with the recirculating aquaculture system (RAS). Their impact on the fish was evaluated with a morphological assessment of the gills, as these are organs susceptible to environmental changes. Trout of 350 -500 g body mass were caught for trial in spring and autumn, with 36 fish originating from 3 fish farms with the FTS system and an equal number from 3 RAS fish farms (n = 6). The fish were macroscopically examined and the gills were investigated microscopically (haematoxylin and eosin staining). Hypertrophy and hyperplasia were most commonly detected, amounting to 89% of all structural abnormalities. These lesions were slightly more common in the FTS, especially in autumn, whereas the changes to the blood vessels in the gills were observed more frequently in the rainbow trout from the RAS system than in the fish obtained from the FTS technology (the difference was statistically significant). The morphological lesions in the mucous cells of the gills were detected at a comparable severity regardless of the technology or production season. The predominantly low values of the histopathologic indices, which described the microscopic lesions in the gills of fish from the FTS and RAS systems, showed that the examined organ was most often free of lesions or demonstrated only minor morphological damage regardless of the production technology.

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