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Malformations/anomalies in the development of cestodes
Aliaskerova, Madina ; Schreiber, Manfred (advisor) ; Chanová, Marta (referee)
Anomalies in tapeworms can appear spontaneously under natural conditions, at both morphological and developmental level. In adult tapeworms, malformations at morphological level are manifested on the scolex and strobila. Their detailed description can be found in Taenia saginata, Taenia pisiformis, Taenia solium, Dibothriocephalus nihonkaiense, Dibothriocephalus latus, Hymenolepis nana and Hymenolepis microstoma. In the larval stages of Taenia crassiceps, the malformations occur predominantly on the skolex. Morphological malformations may be manifested by multiplication of suckers or change in the appearance and number of hooks, change in the structure of the genitalia, occurrence of lateral segments, fenestration of the strobila or occurrence of multiple planes of symmetry. However, these malformations can also be caused by targeted radiation exposure, temperature stress or anthelmintics. Developmental anomalies are also manifested by spontaneous appearance of tapeworms in different parts of the body in different host species. There is a link between anomalous infections and the immune status of the host. Possible causes of anomalies include damage to neoblasts, lack of a proper immune response by the host, anthelmintics, host diet, or environmental influences.
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Murine cerebral toxocariasis
Bernardová, Nicol ; Chanová, Marta (advisor) ; Panská, Lucie (referee)
Toxocara canis is endoparasitic geohelminth of canids. In its life cycle it uses paratenic host (even humans) and can cause severe problems called cerebral toxocariasis when attacks central nervous system. The exact mechanism of pathogenicity in nervous system is unknown and experimental studies examines rather the acute phase of toxocariasis, therefore we characterized the course of cerebral toxocarosis in mice from acute to chronic phase in this master thesis. We found larvae of the parasite in the brains of mice. The larvae in the tissues occurred both, individually and in clusters. The presence of larvae was observed in regions that affect both movement and memory. We did not find any visible injury nor inflammation surrounding the larvae in the tissue. However, histological examination showed brain tissue pathologies in all mice, namely local necrosis, hemorrhages, thickened vessel walls, cell infiltrates in tissue and around vessels and abnormal angiogenesis. The mice showed neurological symptoms with increasing frequency from the 9th week post infection. Production of specific antibodies was also monitored. The level of antibodies in reinfected mice was higher compared to antibody levels of mice with a single infection. No correlation with the presence of neurological symptoms was shown. Key...
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Effect of selected antiparasitic drugs on Trichobilharzia regenti
Lípová, Pavlína ; Horák, Petr (advisor) ; Chanová, Marta (referee)
Praziquantel is a drug of choice for the treatment of schistosomiasis caused by human species of the genus Schistosoma. The effect of the drug on avian schistosomes is not completely known. Monensin is a drug used for the treatment of coccidiosis, and its effect on avian schistosomes is unknown. In the thesis, we studied the effect of these drugs on avian schistosome Trichobilharzia regenti. Under in vitro conditions, both drugs were effective after 6 hours of incubation. Praziquantel causes an extensive vacuolization of the whole body, while monensis treatment causes vacuolization of the anterior part of body. Higher concentration of praziquantel causes depolymerization of myofilaments and separation of surface membranes. Monensin did not impair muscles, but caused separation of tegumental layer from the basal membrane. Schistosomula in ducks were not killed by the drugs under in vivo conditions, but the worms were damaged by the drugs. Praziquantel caused vacuolization of the tegument and separation of membranes from the surface. Only vacuolization of the tegument occurred in schistosomula from ducks treated with monensin . No damage to the muscles was observed in the case of both drugs. Histological evaluation of the nerve tissue showed that thero no difference between treated and control duck....
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Migration and pathogenicity of neurotropic helminths
Pech, Václav ; Horák, Petr (advisor) ; Chanová, Marta (referee)
A neurotropism of helminths can be observed in their intermediate, paratenic and definitive hosts. Neurotropic helminths migrate through the nervous tissue, where maturation and reproduction can take place. The neurotropic helminths can be found in the family of trematodes (Diplostomum baeri, D. phoxini, Ornithodiplostomum ptychocheilus, Trichobilharzia regenti), cestodes (Taenia multiceps, T. solium) and nematodes (Angiostrongylus cantonensis, Elaphostrongylus cervi, Parelaphostronglus tenuis, Baylisascaris procyonis). Presence of these helminths in the nervous tissue can (usually with contribution of the immune system) lead to neurological or other pathological changes: the infected hosts can even die. Some of the neurotropic helminths (A. cantonensis, B. procyonis, T. solium, T. multiceps) can infect humans as well.
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Differentiation of totipotent germinal cells in larvae of bird schistosomes
Peštová, Jitka ; Horák, Petr (advisor) ; Chanová, Marta (referee)
This thesis aims to explore the larval development of a bird fluke Trichobilharzia regenti in its intermediate hosts, as well as the processes of differentiation of its embryonal cells and the differentiation between sporocystogenesis and cercariogenesis in sporocysts, with the ultimate goal to find out whether it is possible to find multiple generations of daughter sporocysts throughout the development of avian schistosomes in the intermediate hosts, just like in the case of human schistosomes of genus Schistosoma. Five developmental stages of daughter sporocysts, and ten developmental stages of cercariae have been defined. The first developmental stage in both larvae is the germinal cell. It divides and gives rise to a cell agregate. Afterwards an envelope (primitive epithelium) is formed around the embryo and subsequently, the embryo elongates. At this stage, the development of the two larvae undergoes different pathways. We can distinguish daughter sporocyst from cercaria in the phase, when the tegument is completed. The daughter sporocyst acquires characteristic vermiform appearance, and its body cavity contains plenty of germinal cells. For cercariae with an developed tegument, presence of the penetration glands is characteristic. Key words: Trichobilharzia regenti, germinal cells, mother...
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Modulation of murine immune reactions by selected helminths
Pavlíková, Veronika ; Chanová, Marta (advisor) ; Leštinová, Tereza (referee)
Currently, the use of helminths in alternative treatment of immune mediated diseases is an attractive topic. Their therapeutic potential is justified by the ability to modulate the host immune system. To test this potential, we chose the flukes of Schistosoma mansoni, which is known to immunomodulate its hosts significantly, however also act as a strong pathogen. Due to high pathogenicity of classical infections we tried to compare its immunomodulation efficiency with alternative interactions of S. mansoni with the host. We tested a low-dose infection, nonproductive infection, immune stimulation with living or dead eggs (antigens) and restimulation by both, living and dead eggs. Stimulation with eggs was, for the short term, most effective in suppressing inflammatory immune response. From the long term point of view, low-dose infections. were most effective. Use of egg antigens has affected the immune system very poorly and nonproductive infection had no effect at all. Induction of experimental colitis and differences in the subsequent development in various models partially confirm our findings.
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BIRD SCHISTOSOMES: development of schistosomula with focus on Trichobilharzia spp
Chanová, Marta ; Horák, Petr (advisor) ; Špakulová, Marta (referee) ; Haas, Wilfried (referee)
5 ABSTRACT Schistosomulum is the first stage developing in definitive host body, affecting various body parts and in the case of bird schistosomes present in host tissues for longest period. The aims of the present thesis are to summarize recent knowledge of bird schistosomula migration, development and pathogenic impact on host tissues and complete the details for two model species (Trichobilharzia szidati and T. regenti) with different life strategy. The other aim was to introduce and test the method for in vitro cultivation of schistosomula. Schistosomulum is formed by transformation of cercaria in the host skin at the time of penetration. The process is preceded by cercarial tail detachment and includes emptying of penetration glands and extensive surface changes. All this take place also under defined in vitro conditions. Transformed schistosomula migrate towards the target organ in host body. Depending on the species schistosomula migrate via the circulatory system or nervous tissues and the migration is directed either to intestinal or nasal area (visceral or nasal species, respectively). Specific migratory pattern for lung passage of T. szidati and migratory route of T. regenti through the nervous system, unique among schistosomes and including intra- and extra vascular location, are obligatory for...
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Larval toxocarosis and CNS
Bernardová, Nicol ; Chanová, Marta (advisor) ; Bulantová, Jana (referee)
Toxocara spp. is an obligate endoparasitic worm of digestive system of canine and feline. During its life cycle the larvae of this parasite can get even into humans and encapsulate in their tissues. If the presence of toxocara larvae in body causes clinical manifestation, then we talk about larval toxocarosis. We can divide it into several forms and this bachelor's thesis is focused on neurotoxocarosis which is caused by toxocara larvae in the nervous system. This thesis summarises basic information about toxocara, its life cycle and hosts and also about its extension in the world (epidemiology), diagnosis, model animals and finally focusing on clinical manifestation of neurotoxocarosis. Key words: larval toxocarosis, neurotoxocarosis, Toxocara canis, migration, paratenic host, definitive host
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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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