In the rudd aged two years and infected with Ligula intestinalis plerocercoids the relation between its body weight and lenght (longitudo corporis) was described as W=0.0129xL. The analogous relationship in healthy fish was W=0.0166xLAt a relative infection intensity of 7.99 per cent, the infected fish were about 29.5 per cent lighter than the healthy ones. The difference between the mean body length of infected and healthy fish was not significant (p<0.05). The infection occured mainly in early spring. Plerocercoids showed a regular increase of weight during the year. An average infection extensiveness was 31.6 per cent and it underwent seasonal changes with vertices in early summer and autumn. Fish infected with more than one plerocercoid displayed an increased death rate in summer months.
Soil contantination with Toxocara spp. eggs in the Katowice area and its environs. Toxocara spp. is a nematode which causes ,,larvae migrans visceralis'' syndrome in human, especially in children. Cats and dogs are the source of infective eggs of this parasite in human environment. The eggs appear in a soil of urban and rural areas in large number. We have investigated samples of a soil from the recreation areas in Katowice city and its suburbs. The goal of this study was to determine the degree of soil contamination with eggs of Toxocara spp. Of 157 samples examined 79 (50%) contained the eggs. The highest number of eggs has been found in samples collected from landscapes, particulary from the lawn and playgrounds.