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Odors attractive to sand flies and mosquitoes
Strejc, Vojtěch ; Volf, Petr (advisor) ; Štáfková, Jitka (referee)
This thesis focuses on the odour signals used by blood-sucking insects to locate their hosts. It focuses mainly on phlebotominae sand flies, but also deal with the most important findings published for mosquitoes, which are close relatives of sand flies. In addition to sex pheromones, odor signals important to sand flies include carbon dioxide, higher alcohols, aldehydes, alkanes, ketones, and lactic acid. Sand flies and mosquitoes are also attracted to plant kairomones, such as terpenes, because they obtain their sugar meal from plants. In humans, it is known that various individuals are differently attractive to mosquitoes, this individual variability is mainly due to the skin microbiome. In sand flies, significantly different attractivity to Lutzomyia longipalpis was described among six volunteers. Part of this thesis focuses on the increased attractiveness of infected hosts for vectors (mosquitoes and sand flies). Mosquitoes of the genus Anopheles were in some studies more attracted to humans infected with Plasmodium falciparum, specifically those individuals who had gametocytes in their blood. Plasmodium falciparum apparently affect the vector in host selection by altering the odor of the host's sweat or breath to make it more attractive to mosquitoes. Similarly, sand flies are more attracted...
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Sauroleishmania-sand fly interactions
Tichá, Lucie
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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Effect of temperature on sand fly biology and Leishmania transmission
Charvátová, Lada ; Sádlová, Jovana (advisor) ; Dvořák, Vít (referee)
and keywords The current rise in air temperature causes a range of global changes, affecting many species of organisms and their interactions. Phlebotomine sand flies are small members of Dipteran insects of the family Psychodidae, subfamily Phlebotominae, transmitting Leishmania, parasitic flagellates (Kinetoplastida: Trypanosomatidae) that cause the important human disease leishmaniasis. Based on the literature review, the external temperature significantly affects the biology of sand flies. High temperature accelerates their metabolism and shortens the growth rate of immature stages, also influencing body size and body weight (faster development in higher temperatures makes them smaller). The time needed for blood digestion is also reduced, and female defecation and oviposition are accelerated. On the other hand, cold temperatures prolong growth, and cause lower emergence of adult sand flies, slower digestion of blood, or number of laid eggs. Very high or very low temperatures can cause diapause in the larval stage or eggs. In general, the optimal temperature to cover all of their physiological needs is 24-28 řC. Temperature impacts the development of Leishmania in sand flies as well, it is likely that Leishmania has a lower optimal temperature as opposed to sand flies, and therefore some...
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Risk of introducton of leishmaniases into Europe
Přibylová, Helena ; Dvořák, Vít (advisor) ; Vojtková, Barbora (referee)
Leishmania is a genus of parasitic protozoa-causing disease called leishmaniasis. This disease manifests itself in some clinical forms. Proven vectors are phlebotomine sand flies (Diptera: Psychodidae) From more than 900 described species of Phlebotomus to date, probably more than 80 are proven or suspected vectors of leishmanias. The main endemic area is the Mediterranean in Europe, where the proven or suspected phlebotomine sand flies occur. Over the years, more leishmaniasis cases have been reported (more than 10,000 cases of human nonendemic leishmaniasis and more than 700 imported cases of canine leishmaniasis usually from non-endemic European countries). Imported cases of leishmaniasis are mostly reported among tourists and travellers who travel due to their professional reasons (scientists, workmen, soldiers) and migrants. Phlebotomine sand flies spread to new areas and the models, which are based on climate change and the environment, show, that this trend will continue. This thesis tries to discuss some risk factors associated with the potential risk of introducing and spreading leishmaniasis into Europe. Keywords: Leishmania, Phlebotomus, leishmaniasis, introduction, Europe, distribution, risks, hosts, vectors
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Identification and functional studies of sand fly's immune-related genes
Vomáčková Kykalová, Barbora ; Loza Telleria, Erich (advisor) ; Panicucci Zíková, Alena (referee) ; Louradour, Isabelle (referee)
Phlebotomine sand flies (Diptera, Psychodidae) from genera Phlebotomus and Lutzomyia are proven vectors of Leishmania (Kinetoplastea, Trypanosomatida), causative agent of leishmaniases, tropical neglected diseases. To contribute on creating new control strategies we investigated the molecular aspects of interaction between the vector and pathogen on the immunity level. Sand fly innate immunity is based on cellular and humoral events which work synergistically to secure effective protection against pathogens. Here we present our research on humoral aspects of sand fly immunity, specifically on main humoral pathways (Toll, Imd, and Jak- STAT), their genes and function under different conditions especially during Leishmania development in sand fly midgut. We have described gene expression profiles of Toll and Imd - related genes in Phlebotomus papatasi larvae fed with different microbe loads and in adult females infected with Leishmania major. We have identified three antimicrobial peptides (AMPs) in P. papatasi and followed their expression profiles during parasite infection and described a gut-specific defensin upregulated by Leishmania infection. We have proven that the knockdown of defensin genes in P. papatasi supports Leishmania infection and negatively affects sand fly survival. Moreover, we...
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Susceptibility of European vector species to leishmaniases spreading into Europe.
Hošková, Anna ; Sádlová, Jovana (advisor) ; Kodym, Petr (referee)
The first part of this thesis is focused on testing the ability of selected European sand fly species to support the development of Leishmania major, L. donovani and L. martiniquensis. A total of 15 experimental infections were performed and 1601 female sand flies were analysed. The results show that Phlebotomus perniciosus and P. tobbi support development of L. major and L. donovani (mature infections with colonization of the stomodeal valve and metacyclic promastigotes developed), while L. martiniquensis did not survive defecation. The vector competence of Sergentomyia minuta to Leishmania could not be tested because the females of this species refused to take blood meal on feeders, although several types of membranes, blood and experimental conditions were tested. Further, biting midges were studied in two areas of Czech equine autochthonous cases of L. martiniquensis. A total of 3341 bloodfed and parous females from Slatiňany and 119 from Ústí n. L. were analysed. The most abundant were biting midges from the Culicoides obsoletus complex. None of the 97 pools were positive for Leishmania DNA, but in 15 pools from Slatiňany was detected DNA of Herpetomonas ztiplika and one pool from Ústí n. L. contained DNA of Trypanosoma sp. from T. theileri group. The isolation of L. martiniquensis was...
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Experimental animal models and vectors of Leishmania (Mundinia)
Bečvář, Tomáš
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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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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