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This study reveals the presence of hantaviruses in free-living rodents and insectivores in urban areas in the Czech Republic. A large number of hantavirus reservoir hosts were tested for hantavirus RNA in different tissues, using universal and specific primers for amplification of the large and medium fragments of hantavirus genomic RNA. Phylogenetic relationships of obtained nucleotide sequences of hantaviruses were reconstructed. Four different species of hantaviruses were detected, including two species pathogenic (or potentially pathogenic) for humans, suggesting a threat for public health. Additionally, inter-family spillover infections and hantavirus species-associated tissue tropism were recorded in rodent hosts.

The Trypanosoma theileri group are blood parasites of ungulates. Confirmed vectors of these protists are horseflies or sheep keds for T. melophagium, but these trypanosomes were also detected in deer keds, mosquitoes and phlebotomus. We targeted on the investigation of possibility mosquitoes acting as vectors and additionally we targeted on the prevalence of T. theileri in mosquitoes at selected locations in the Czech Republic due to previous positive detection there. The measured prevalence has reached 6,4 % in mosquitoes, 4 % in deer keds and 16,7 % in sheep keds. The aim of experimental infections was to discover a potential of mosquitoes and phlebotomus acting as vectors of the T. theileri. Phlebotomus perniciosus and three species of mosquitoes Culex pipiens molestus, Culex pipiens quinquefasciatus and Aedes vexans were used for those experiments. Furthermore, isolates of T. theileri and T. melophagium from different sources were used. The divergence among these isolates and among used species of insect was found. The best results were achieved with Ae. aegypti and isolates from mosquitoes, where prevalence had reached 90,8 %. The infected mosquitoes were used for prediuresis research which had shown infection forms of the trypanosomes in the urine liquid. The phylogenetic analyse of T....

Dermatophytes are a group of phylogenetically related microscopic fungi of the order Onygenales, the Arthrodermateceae family, capable of using keratin as a source of nutrition. Some species are important pathogens of vertebrates including humans. The aim of my bachelor thesis was to summarize the current knowledge about virulence factors of dermatophytes, taking into account their possible role in the host specificity. In the main part, I describe the virulence factors, pathogenesis mediating molecules, in the context of the individual stages of infection, such as adherence, degradation of the keratin, or suppression of the immune response. The study of these factors in general, deserves increased attention because their knowledge can lead to the development of targeted treatment. Some aspects of pathogenesis, e.g. keratolysis and fighting the immune system, are relatively well studied. However, we know almost nothing about the other factors, especially about those mediating host sensing and adherence, but they could provide important information on identifying the host specificity of dermatophytes. The final chapter is dedicated to a discussion about the potential ability of these virulence factors to influence the selection of the host. My thesis brings a comprehensive overview of the...

The class Kinetoplastea contains free-living and parasitic species. One of the most dominant group within the class is the order Trypanosomatida which includes obligate parasites (Trypanosoma, Leishmania) infecting a wide range of hosts. Some species are serious pathogens of humans and domestic animals and cause considerable losses. However, the majority of trypanosomatids belongs to monoxenous parasites of insect which are usually harmless to their hosts. Monoxenous trypanosomatids predominantly infect Hemiptera and Diptera. This diploma thesis is focused on the detection of monoxenous trypanosomatids in cockroaches captured in the Czech Republic and cockroaches from different breedings. Cockroaches are very suitable mechanical vectors of many different pathogens (including parasites) and are significant health threat for humans and animals. First trypanosomatids in cockroaches were documented at the beginning of the 20th century, but there is no study focused on this topic specifically. Another aim of this thesis is morphological and ultramicroscopic analysis and the study of the host specificity of the recently described species Herpetomonas tarakana, isolated from a cockroach. My findings were partly used in the already published study "Diversity of trypanosomatids in cockroaches and the...

This bachelor thesis deals with fungal parasites which are an important factor that affects the dynamics of microalgal communities. Here I sum up the knowledge of parasites especially from Oomycota and Chytridiomycota along with a little focus on other groups. The basic characteristics of these fungal parasites, such as their host specificity and factors that affect their spreading ability between algal hosts, are summarized. The abiotic factors such as light and temperature, which are the most important factors causing epidemic, are mainly discussed. The fungal parasites can change the maximal population size and are able to alter the competitive relationships in microalgal communities. These factors are discussed in individual algal groups. The fungal parasites could be a negative economic player of the bioindustry and their future role in this industry is also discussed. Key words: parasite, host, host specificity, communities dynamics, algae, fungi, phytoplankton

The twisted-wing parasites (Strepsiptera) are an endoparasitic order of insects with cosmopolitan distribution, which are sister group of Coleoptera. There are about 600 known species up to date. Strepsiptera parasitize seven insect orders (Thysanura, Orthoptera, Blattodea, Mantodea, Hemiptera, Diptera, Hymenoptera). The family Xenidae is one of the most derived groups of Strepsiptera. Its representatives parasitize aculeate Hymenoptera of three families (Vespidae, Sphecidae, Crabronidae). In comparison to the basal groups, there are well-known hosts for genera of the family Xenidae. Therefore, this group is suitable object for study of the evolution of host specialization. Phylogeny of the family Xenidae was constructed on the basis of molecular analysis of three genes. Moreover, the mapping of ancestral host major groups and biogeographic areas was performed using two methods (parsimony, maximum likelihood). According to the results, the family Xenidae is monophyletic group with Old World origin. There were a several independent switches to the same host groups. This significantly changes the existing ideas about evolution of host specialization and requires a taxonomic revision. Within the family Xenidae, there were several cases of dispersal between the Old World and the New World. Furthermore,...

The twisted-wing parasites (Strepsiptera) are entomophagous insect order with cosmopolitan distribution. There are about 600 known species up to date. In spite of this, they have very broad host spectrum. Strepsiptera parasites in seven insect groups (Thysanura, Blattodea, Mantodea, Orthoptera, Hemiptera, Diptera, Hymenoptera). The mutual relationship between genera or even between species are not known, except for the species list and the host specification. Moreover, there is an anambiguous use of their species concept. Some authors consider Strepsiptera as the specialists and they match almost every host species with one separate strepsipteran parasite. The opposite concept is to consider strepsiptera as the generalists. The presence of the crypctic species also affect our understanding of the diversity of Strepsiptera. Therefore, the knowledge of Strepsiptera phylogeny provide us the important information about species diversity of studied group as well as about their coevolution with their hosts. On the basis of molecular analyses of three genes constructed the phylogeny genus Stylops. This genus has the wider spetrum of the host species from other strepsipterans of Stylopidae, It is obvious, that strepsipterans of genus Stylops are mainly specialised on their host subgenus. There was detected two...

Arbuscular mycorrhiza (AM) is a symbiotic interaction between vascular plants and arbuscular mycorrhizal fungi from phylum Glomeromycota. AM symbiosis is considered as a nonspecific interaction, because AM fungi are able to colonize roots of all plant species which are hosts for this type of symbiosis, nevertheless certain specific interactions exist between the partners. The specificity can be evident on the level of the formation of mycorrhiza, which means that different species of plants can vary in the composition of fungal community in their roots or AM fungi can differ in an ability of colonization and sporulation depending on host plant species. The specificity can also manifest as different functionality of the symbiosis in dependence on the particular partners affecting the mycorrhizal response of the host plants. All of these specific interactions can have an impact on the coexistence and diversity of plants in communities.

Avian contact zones were suggested to act as barriers to parasite expansions. I studied haemosporidian parasites (genera Plasmodium, Haemoproteus, and Leucocytozoon) of two Nightingale species which meet in a contact zone in Europe. In total 20 lineages of parasites were detected. Surprisingly, all common lineages were shared by the two host species. The parasite prevalence vary between species (Trush Nightingales were more often parasitized than Common Nightingales.) but did not vary to a large extent within zones inside species Parasitemia of the most frequent Haemoproteus LULU1 lineage assessed by Real-Time PCR method did not differ significantly between the two host species. Six out of nine hybrids of the nightingale species were parasitized. Haemosporidian lineages found in hybrids were also frequent in the parental species. In conclusion, the nightingale contact zone seems to have only little (if any) effect on the distribution of haemosporidian parasites.

Host specificity of tropical bark and ambrosia beetles was surveyed by rearing the beetles from 13 host trees in a lowland rainforest in Papua New Guinea. Ploeophagous bark beetles show narrow host specificity (usually family-level) typical for herbivorous insects, fungus-growing ambrosia beetles display almost no host fidelity. In both groups of species, the local diversity of plants is unlikely to have played a role in the clade diversification. The ambrosia symbiosis (scolytine beetles and fungi) is shown to be less specific than previously assumed, based on a discovery of new association between Scolytodes unipunctatus (genus of phloem feeders) and three unrelated groups of ambrosia fungi. The hypothesis that apparent polyphagy may conceal specialized populations within a species of a herbivore is tested for Homona mermerodes (Lepidoptera, Tortricidae). The haplotype diversity of the species show no congruence with host plants or geographic origin, confirming polyphagy of the species.