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Sauroleishmania-sand fly interactions
Tichá, Lucie ; Volf, Petr (advisor) ; Berriatua Fernández de Larea, Eduardo (referee) ; Shaw, Jeffrey Jon (referee)
Sauroleishmania is a group of less studied parasites that belong to the genus Leishmania (Kinetoplastida: Trypanosomatidae). They circulate between reptile hosts and sand fly vectors (Diptera: Psychodidae). Due to the non-pathogenic character of its species, little is known about their development in reptiles and sand flies. The main objective of this project was to elucidate some missing aspects of Sauroleishmania life cycle. A major part of this thesis aimed to test the susceptibility of various sand fly species to different Sauroleishmania isolates and describe their development in the sand fly intestinal tract. A minor part was devoted to the study of infection in reptiles. First, we investigated the development of Leishmania (Sauroleishmania) tarentolae in three Phlebotomus species. Sand flies were infected through membrane on promastigote suspension and dissected at various time intervals post infection. Leishmania (S.) tarentolae developed in all three species tested and underwent peripylarian type of the development. Moreover, heavy parasite loads were frequently found in Malpighian tubules, which is a unique localization among Leishmania parasites. To summarize the current knowledge on L. (S.) tarentolae, we have also written a review describing the origin, life cycle and application of...
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Experimental animal models and vectors of Leishmania (Mundinia)
Bečvář, Tomáš ; Sádlová, Jovana (advisor) ; Courtenay, Orin (referee) ; Soares Maia, Carla Alexandra (referee)
Leishmania are vector-borne dixenous protozoan parasites of vertebrates causing diseases collectively called leishmaniases, which threaten more than 1 billion people mainly in tropical and subtropical regions. These parasites are divided into four subgenera: Leishmania, Viannia, Sauroleishmania, and Mundinia. The last named are geographically widely dispersed and their distribution covers all continents except Antarctica. Although their medical and veterinary importance is increasing, there is currently almost no information on natural reservoir hosts, vector species, and experimental research options due to the very limited range of model animals. This thesis summarizes our efforts to unravel possible vectors and laboratory models for this subgenus. In the first three studies, we focused on potential models; therefore, we experimentally infected guinea pigs (Cavia porcellus), BALB/c mice, Chinese hamsters (Cricetulus griseus), and steppe lemmings (Lagurus lagurus) with five species of Mundinia and we also tested reservoir potential of African grass rat (Arvicanthis niloticus) and Natal multimammate mouse (Mastomys natalensis) to Leishmania chancei. The second part focused on potential vectors of the parasites. We experimentally infected biting midges Culicoides sonorensis and sand flies sharing...
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Early phase of anti-Leishmania immunity in the host skin
Máčalíková, Bára ; Leštinová, Tereza (advisor) ; Kolářová, Iva (referee)
Leishmania parasites are parasitic protozoans that cause disease called leishmaniasis, which primarily affects mammals. Throughout evolution, Leishmania has adapted to the host's immune system, using it to its advantage. This bachelor's thesis describes the relationship between Leishmania and early immune components in the host's skin, as well as the parasite's ability to inhibit the microbicidal activities of cells. The infection begins with the inoculation of infectious promastigotes into the skin, and before reaching their target cells, Leishmania primarily interacts primarily with the complement system, keratinocytes, fibroblats, eosinophils, neutrophils, mast cells and dendritic cells. Understanding the mutual interaction between the host and the parasite is essential for vaccine development and the treatment of leishmaniasis. KEYWORDS: leishmania, skin, early imunity, complement system, keratinocytes, fibroblasts, eosinophils, neutrophils, mast cells, dendritic cells
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Use of animal models in Leishmania research
Pekařová, Julie ; Vojtková, Barbora (advisor) ; Pacáková, Lenka (referee)
Leishmaniasis is a disease caused by parasitic protozoa of the genus Leishmania, whose life cycle includes a mammalian host and an insect vector, typically of the genus Phlebotomus or Lutzomyia. While the number of vectors is limited, the spectrum of hosts is wide. Therefore, there are also many animal models that can be used for the study of different aspects of leishmaniasis. These include the study of the host's immune response, pathological manifestations of diseases, virulence factors or testing drugs and vaccines. Commonly used animal models are mainly rodents, which make up a large part of reservoir hosts of leishmaniasis. Examples of standard rodent models are the laboratory mouse (Mus musculus) and the golden hamster (Mesocricetus auratus), however, higher models such as non-human primates or dogs are also being used. Animals that are relatively new to leishmaniasis research are wild rodents, which appear to be ideal experimental models for studying the natural dynamics of infections. Key words: animal models, laboratory animals, rodents, Leishmania, leishmaniasis
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Host immune response in cutaneous versus visceral form of leishmaniasis
Matějková, Barbora ; Leštinová, Tereza (advisor) ; Jelínková, Kristýna (referee)
Parasitic protozoans of the genus Leishmania circulate between vectors and hosts during their life cycle, in which they come into contact with the immune system. In the host body, infection can lead to the development of a disease called leishmaniasis. This can manifest itself in a number of ways, with the best known forms being referred to as visceral, mucocutaneous and cutaneous leishmaniasis. This thesis focuses on the host immune response during the cutaneous and visceral forms of leishmaniasis. In addition, attention has been given to host, vector and parasite factors that differ between cutaneous and visceral leishmaniasis forms and that may influence the different clinical manifestations. Attention is paid not only to factors related to immunity, but also to factors such as parasite inoculum dose sizes, temperature differences between skin and internal organs, parasite genetics, and others. Keywords - Leishmania, visceral leishmaniasis, cutaneous leishmaniasis, immune response, parasite, immunity
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Development of flagellates of the genus Porcisia and subgenus Mundinia in phlebotomine sand flies (Diptera: Psychodidae) and ceratopogonid midges (Diptera: Ceratopogonidae)
Bačíková, Dominika ; Sádlová, Jovana (advisor) ; Modrý, David (referee)
The main part of the thesis is focused on flagellates of the genus Porcisia, parasitizing Neotropical porcupines with unknown vectors. The development of two known species of this genus (P. deanei and P. hertigi) in two sand fly species (Lu. migonei, Lu. longipalpis) and biting midges C. sonorensis was studied using experimental infections. While P. hertigi did not survive defecation in females of either vector, P. deanei formed strong mature infections in 51-61% of Lu. longipalpis and in a smaller percentage in Lu. migonei (7 %) and C. sonorensis (7 %). Porcisia showed significantly smaller size than the control species L. infantum but formed the same morphological forms. The localization of P. deanei was exceptional; infections were detected predominantly in Malpighian tubules. Further experiments demonstrated the presence of P. deanei in the urine of Lu. longipalpis excreted during prediuresis and successful transmission of parasites to BALB/c mice by this unique route. Thus, Lu. longipalpis is a competent vector of P. deanei, but other vector species may be involved in transmission at endemic localities. A minor part is focused on the comparison of the morphology of two Mundinia species - L. martiniquensis and L. orientalis - during development in biting midges C. sonorensis and sand flies Ph....
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Factors affecting the protective effect provided by sand fly saliva immunization on the outcome of Leishmania infection
Jelínková, Kristýna ; Kolářová, Iva (advisor) ; Lipoldová, Marie (referee)
ENGLISH VERSION Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania, transmitted by its vector - female sand flies during the process of blood feeding. Preexposure to sand fly saliva prior to Leishmania infection affects the host immune system, leading to possible establishment of protective effect on the disease outcome. This effect is based on the delayed type hypersensitivity reaction to sand fly saliva which has been shown to peak about 48 hours after antigen encounter, leading to the more effective host immune response towards the Leishmania parasites. In this project, we found this protective effect as species-specific, additionally dependent also on the timing of the infection post last immunization. Results of presented experiments showed that infection of BALB/c mice with Leishmania major performed after 48 hours post last Phlebotomus duboscqi sand fly saliva immunization, did not confer protection in comparison to infection performed at one-week after the last exposure. Moreover, the effect of the sand fly saliva pre-exposure was at this shorter timing of infection rather diminished, supported by insignificant differences in the measured parameters compared to the unpre-exposed infected control group. Additionally, immunization with sand fly Sergentomyia...
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Genetic regulation of Leishmania infection
Sohrabi, Yahya ; Lipoldová, Marie (advisor) ; Krulová, Magdaléna (referee) ; Kolářová, Iva (referee)
6 Abstract Leishmaniasis is a neglected tropical disease, which belongs to the top health problems because it is endemic in 98 countries in Asia, Africa, the Americas and the Mediterranean region, and is gradually expanding to new areas, including Central Europe and USA. Clinical manifestations of leishmaniasis include a diverse range of forms, ranging from non-lethal cutaneous leishmaniasis to potentially lethal visceral leishmaniasis. Asymptomatic cases are known to exist in endemic areas. Different species of Leishmania induce distinct symptoms, but even the patients infected by the same species develop different symptoms and may respond differently to the treatment. Thus, one of the challenges is to explain the observed variability of leishmaniasis that cannot be attributed to the currently known factors. To find novel regulatory factors of the disease we tested molecules that were shown to play role in other infections and mapped loci controlling parasite load after L. major infection. We also determined genetic control of survival after infection with tick-borne encephalitis virus (TBEV) in order to establish whether there are common elements in response to L. major and TBEV. Interferon-induced GTPases (guanylate-binding proteins, GBPs) play an important role in inflammasome activation and mediate...
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Gene engineering methods in Leishmania research
Kriegová, Gabriela ; Bečvář, Tomáš (advisor) ; Arbonová, Lenka (referee)
Gene engineering methods are now increasingly used in the study of leishmania. These modern DNA technologies make it possible to manipulate with the genome of organisms, allowing it to be altered and repaired. The most important methods include CRISPR/Cas9, RNA interference (RNAi), dimerizable Cre recombinase (DiCre), plasmid shuffle and gene tagging. The choice of method depends on whether essential or non-essential genes are being studied as well as the reason of the study. These methods investigate leishmania using a reverse genetics approach that allows the phenotype to be studied. This work summarizes the current knowledge on the use of gene engineering methods in Leishmania, the necessary modifications of the procedures and discusses their limitations and advantages.
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Leishmaniases and their vectors in western Africa
Hošková, Anna ; Dvořák, Vít (advisor) ; Sádlová, Jovana (referee)
Leishmaniasis is a parasitic disease transmitted by sand flies. In West Africa, leishmaniasis is endemic and we distinguish cutaneous, visceral and mucocutaneous form of the disease. The most common form in this area is cutaneous leishmaniasis, which is caused by Leishmania major, Leishmania tropica and a new, as yet undescribed species Leishmania sp. from Ghana. The causative agents of visceral leishmaniasis are Leishmania donovani and Leishmania infantum. Phlebotomus duboscqi is a confirmed vector of L. major in this region. Vectors of Leishmania sp. from Ghana and vectors of visceral leishmaniasis remain unknown in West Africa. Sand flies of the genus Sergentomyia or Culicoides biting midges are considered as potential alternative vectors in this area. The confirmed reservoir hosts of L. major in some countries are the rodents Tatera gambiana, Arvicanthis niloticus and Mastomys erythroleucus, but in most states they are not confirmed. The reservoir hosts of visceral leishmaniasis are mainly dogs. Some West African states used to be French colonies, and there are many people of African descent in France who come to visit their relatives in West Africa. This poses a risk of import of leishmaniasis to non-endemic areas. The aim of this bachelor thesis is to summarize the current knowledge about the...
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