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Schistosoma mansoni (Trematoda): Differences in the biology of geographical strains
Žirovnická, Tereza ; Macháček, Tomáš (advisor) ; Peterková, Kristýna (referee)
This bachelor thesis discusses the geographical strains of the fluke Schistosoma mansoni and summarizes the knowledge of their differences. The thesis aims to conduct literature research of comparative studies mentioning descriptions of specific strains of S. mansoni and then to identify differences across those geographic strains. Among the relevant data subjected to comparisons, besides morphological and anatomical differences, the prepatent period, the distribution of eggs in the host and the caused pathology, including the granuloma formation, were mentioned too. The results of this work confirm that the specific geographical isolates differ from each other in various aspects, often even within the same strain. Geographic strains are unevenly represented in studies, and this may bias our view of selected aspects of schistosome biology through the results of dominant strains. It is therefore important to encourage further, diversified research that considers all experimental factors. The obtained knowledge about the characteristics of geographic strains can provide important information for the development of strategies to control schistosomiasis and benefit negatively affected populations worldwide. Keywords: Schistosoma mansoni, schistosomiasis, geographical strain, comparative analysis,...
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Recent diagnostic challenges in schistosmiasis
Liberdová, Jana ; Chanová, Marta (advisor) ; Horák, Petr (referee)
Schistosomiasis is debilitating waterborne helminthiasis of global medical and veterinary importance. It is caused by digenetic trematodes of the genus Schistosoma. More than 250 million people are currently infected, and 700 million people are at daily risk of acquiring this neglected tropical disease. Schistosomiasis is prevalent mostly in sub-Saharan Africa, particularly in poor communities living in impoverished conditions with limited access to safe water. The global control of this disease relies on single drug-oriented preventive chemotherapy campaigns. Changing epidemiological situation together with the general nature of this parasitosis (long-term development in several phases, multiorgan pathogenesis with complex manifestations) makes its diagnosis difficult. Current diagnostic standards may be unreliable in many specific settings, and their universal use needs to be reconsidered. In schistosomiasis diagnostics, the choice of specific methodology should be made accordingly to the particular situation requirements. The present thesis reviews recent approaches and challenges in schistosomiasis diagnostics. Key words: schistosomiasis, diagnostics, neglected diseases, global control, elimination
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Laboratory cycles of schistosomes, breeding of intermediate snail hosts and their ecological requirements
Nečasová, Monika ; Mikeš, Libor (advisor) ; Horák, Petr (referee)
The Schistosomatidae family is an important group of blood flukes, including serious human and livestock animal pathogens. With regard to reproduction, they are gonochoristic parasites. Their life cycle has two stages - asexual reproduction in an intermediary host (fresh water and sea gastropods) and sexual reproduction in the definitive host (mammals and birds). With regard to their pathogenicity at the definitive hosts, the blood fluke life cycle is abundantly maintained in laboratories. To preserve the whole cycle, the intermediary host gastropods are very important, They can include, without limitation, representatives of the Lymnaeidae family. However, their sensitivity to parasitism by blood flukes varies significantly by species. Floats were classified into several genera according to various parameters in the past. The systematics was most frequently based on anatomic and morphological differences. However, the most precise taxonomies are based on molecular data and mutual phylogenetic relationships of Lymnaeidaegastropods remain a subject of research. It is a fresh water family of gastropods with specific ecological and nutritional requirements. Summary information about their ecology estimate that the float gastropods are highly sensitive to the presence of heavy metals in water, such as...
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Excretory-secretory proteins of schistosome intravertebrate stages in context of their biology
Konečný, Lukáš ; Mikeš, Libor (advisor) ; Kašný, Martin (referee)
Schistosomatidae is a family of blood-dwelling trematodes which cause serious disease in humans and warm blooded animals. Human schistosomiasis affects over 258 million people worldwide. The fundamental pathological manifestations of the disease are not caused by adult worms, but by responses to antigens released from eggs, which remain trapped in the tissues. All stages of these parasites release excretory-secretory products, which mostly comprise of proteins which are, to a certain extent, species- and stage-specific. These products have many functions that play roles in successful transmission of the parasite and its interactions with the host. Various approaches to the collection and analysis of these molecules do not always accurately reflect the secretory processes in vivo, because they always employ in vitro techniques. The research of these secreted molecules discovered many mechanisms, through which the parasite successfully modulates and evades host immune system. Despite the fact, that many of these molecules were identified as potential vaccine candidates, still no sufficiently effective vaccine has been developed. With great technological advances used for the identification of these proteins, this area is becoming more and more topical. This review focuses on composition of...
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