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Fasioloides magna is a trematode parasitizing in the liver parenchyma of ruminants. Its life cycle is associated with the humid environment and includes intermediate freshwater snail hosts from family Lymnaeidae. According to the ability of host to form a certain type of a pseudocyst during fascioloidosis, they can be,divided in three groups, specific definitive hosts (red deers, fallow deers, roe deers), nonspecific definitive hosts (cattle, wild boars and elks) and atypical hosts (sheeps and goats). Beside the natural infections also the experimental infections of other potential host species has been realized (chamois, llama and bighorn sheep and traditional laboratory animals such as mice, guinea pigs, rats and rabbits). In the context of different diseases, many changes in infected organism can occur. These can be qualitatively and quantitatively evaluated. Similarly, during fascioloidosis the changes associated with the presence of the parasite in the host's body is possible to monitor, e.g. antibody production, increase in the number of eosinophils, release of eggs in faeces, internal bleeding, or the level liver damage. The liver damage is corresponding primarily to biochemical parameters of blood, not only the liver enzymes, but also other blood components, like blood proteins, lipids,...

Although to date this fact has been widely neglected, avian plumage is inhabited by a wide range of bacteria able to utilize keratin, the basic structural unit of feathers. If these keratinophilic, so called feather-degrading bacteria (hereafter FDB) get out of control, it can lead to significant changes in the plumage structural properties, resulting in impaired thermoregulation, flight performance, and expression of plumage ornaments. These may have significant consequences on reproductive success and overall fitness of individual. Based on these facts, it is hypothesized that PDB pose strong selective pressure lying behind the evolution of defense mechanisms such as size and chemical composition of uropygial gland, deposition of pigments into the feathers, or molting strategies that have been observed to eliminate the negative effect of FDB. The aims of this bachelor thesis are, on the basis of available literature, to summarize findings related to overall diversity and characteristics of plumage bacteria, to evaluate their effect on quality of plumage and individual fitness, and also to assess a role of microorganism in the evolution of different life- strategies in birds. Finally, this bachelor thesis points out the shortcomings of recent studies and proposes the concept for future research...