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Fasciolosis, caused by the liver fluke (Fasciola hepatica) is an important issue for both human and animal health. The disease evokes economic losses which are a consequence of impaired animal productivity leading to higher costs of meat and milk production, as well as liver condemnation. The goals of this thesis were to: (1) elaborate a molecular method--PCR for the detection of F. hepatica DNA in intermediate and definite hosts; (2) estimate the usefulness of a recombinated cysteine proteinase produced in E. coli in the form of inclusive bodies in serological diagnosis of F. hepatica infection in definite hosts, using an enzyme-linked immunosorbent assay (ELISA); (3) conduct field research on the prevalence of infection among intermediate and definitive hosts (cattle) in chosen regions of Poland, utilizing the elaborated methods. Based on the results obtained in this study, it was established that it is possible to detect F. hepatica DNA in the feces of definite hosts with the elaborated PCR method. The amplification of a 124 base pair tandem repeat allows the detection of fluke larval stages in intermediate hosts within 12 hours of exposure and F. hepatica infection in definite hosts (by the 5th week in rats, 8th week in sheep and 10th week in cattle). Therefore, the PCR test is more sensitive than traditional microscopic methods. Furthermore, it was determined that, the recombinated cysteine proteinase in the form of inclusive bodies, after solubillization exhibits antigenic properties of the native protein and the ELISA method based on this antigen may be useful as a tool for diagnosing fasciolosis in sheep and cattle, in both serum and milk samples. The test achieves a greater sensitivity and specificity than an ELISA based on native excretory-secretory antigens. The results of field research indicate that Fasciola hepatica is a frequent parasite of cattle in central and eastern Poland. The mean prevalence was 34.86% (+/- 16.95) in all studied areas. The prevalence among intermediate hosts varied greatly (0-100%). The elaborated tests were proved to be valuable, mutually complementing diagnostic tools, applicable to different epidemiological situations.

Flow cytometry analysis of leukocytes response in rats immunized and infected with Fasciola hepatica. In the present experiment the differences in blood leucocytes between rats immunised intranasally with cDNA encoding F. hepatica GST, challenged with the parasite (group 1) and non-immunised infected rats (group 2) were compared. The number of leukocytes were estimated by flow cytometry on the 1, 5, 9 week after infection. Changes in the level of blood lymphocytes and monocytes were similar, with an increasing tendency in both groups. The level of eosinophils decreased to the 9th week after infection in both groups, however the number of these cells was seven times higher in control rats than in immunised rats.

The trematode F. hepatica is an internal parasite of many species of animals including men. In ruminants, fasciolosis is an economically important disease often resulting in a chronic and sub-clinical infection. The mechanisms of immune responses of final hosts to this infection are still poorly understood. Experimental and clinical studies reported so far suggest that both humoral and cellular effectors of the immune response are important to control the duration of F. hepatica infection. However, there are considerable variation both inter-species and between various strains of the same species in regulation of the response as well as abilities to develop resistance to subsequent infections.

On the background of informations about frequency of appearance Fasciola hepatica L. among cattle in Poland in the time from 1995-1997, as well es in the former period, there is presented in the article an estimative apperiation of economical losses caused by staggers disease among cattle. The highest extensiveness of invasion of F. hepatica L. among cattle was noticed in the fifties and sixties manty in the north-eastern Poland. Losses caused by confiscation of a liver to amounted to 1 197 031 zł in 1995, 1 277 154 zł in 1996 and 1 312 078 zł in 1997.