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Comparison of different rodent species as hosts of human pathogenic leishmania.
Vojtková, Barbora
6 ABSTRACT Leishmania parasites (Kinetoplastida: Trypanosomatidae) are causative agents of leishmaniases, a group of vector-borne diseases with various manifestations and complex epidemiology. Principal vectors are sand flies (Diptera: Psychodidae) and among mammalian hosts, rodents are predominantly represented. Rodents are also the most common laboratory models for the research of leishmaniases. However, reservoirs of most Leishmania species are still poorly recognized and the scope of standard model hosts is still insufficient to mimic well the wide spectrum of leishmaniases. This PhD thesis summarizes three different topics, all dealing with experimental infections of rodents with important human parasites - Leishmania major and L. donovani. The first topic was focused on the effect of sand fly saliva on the development of cutaneous leishmaniasis. BALB/c mice infected intradermally with L. major were repeatedly bitten by P. duboscqi females every two weeks. The multiple and repeated sand fly bites significantly enhanced the development of cutaneous lesions and increased parasite load. The second topic was aimed at enrichment of the spectrum of laboratory model animals for Leishmania research. Three Asian rodent species (Cricetulus griseus, Lagurus lagurus and Phodopus sungorus) were infected with L....
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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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Potential vectors of leishmaniases in southeastern Asia
Mandysová, Adéla ; Dvořák, Vít (advisor) ; Vojtková, Barbora (referee)
Leishmaniasis are neglected tropical diseases caused by intracellular protozoan parasites of the genus Leishmania. They are transmitted by blood feeding phlebotomine sandflies (Diptera: Psychodidae). The disease occurs in many parts of the world, including southeastern Asia. Recently, the number of human leishmaniasis cases have been increasing in this region. Leishmania martiniquenis and L. orientalis of the subgenus Mundinia are the causative agents of cutaneous and visceral leishmaniasis, L. donovani and L. infantum are the causative agents only of visceral leishmaniasis (also known as kala-azar) here. Domestic animals may serve as natural reservoirs, suggesting their role in zoonotic cycle. Although the fauna of phlebotomine sandflies in this area is rich, no species has yet been proven as a vector of the disease. Recent studies suggest that other groups of insects in the southeastern Asia could transmit the diasease. The potential vectors could be females of the genus Sergentomyia (Diptera: Psychodidae) and also biting midges of the genus Culicoides (Diptera: Ceratopogonidae). Key words: sand fly, leishmaniasis, vector, southeastern Asia, Thailand
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Xenodiagnosis and its use in leishmaniases research
Vojtková, Barbora ; Volf, Petr (advisor) ; Svobodová, Milena (referee)
The aim of these theses was to summarize the knowledge about the use of xenodiagnostic methods in the past and their current potential for parasitological research. Xenodiagnosis it is a diagnostic method using bloodsucking arthropods (disease vectors) as a biologic medium suitable for detection of parasites in the blood of investigated individuals (vertebrates). It is expected that parasites grow within the midgut of the vector and then are easily detectable microscopically. The method was used for the first time in 1914 by French researcher Émile Bumpt for detection of Trypasoma cruzi, causative agent of Chargas' disease. During few decades and thanks to engagement of many scientific groups, it became one of the most efficient and effective diagnostic methods. For instance, the most suitable species of vectors, the experiment duration and the optimal numbers of vectors and/or experiments were assigned to get reliable results. Xenodiagnoses as a diagnostic method lost its importance after introduction of molecular methods, first of all after onset of polymerase chain reaction. At present, however, the xenodiagnosis is suitable for experiments studiing if the host is infectious for the vector. This method appears as a good tool for testing of new reservoir hosts and for the monitoring of the role...
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Genus Sergentomyia and its role in the transmission of Leishmania
Hlavačková, Kristýna ; Dvořák, Vít (advisor) ; Sádlová, Jovana (referee)
Sand flies, members of the subfamily Phlebotominae do not occur in the CzechRepublic, but as near as in the Mediterraneantheir fauna is quite abundant. Sand flies can be found approximately between 50řN and 40řS. Species of genus Phlebotomus, Sergentomyia and Lutzomyia include medically and veterinary important vectors of viral and bacterial diseases as well as leishmaniasis, one of the most important human protozoal diseases. 321 years have passed since the first sand fly was described, but only 110 years ago intensive taxonomic work began. Over the years many classification systems have been proposed, mainly based on division of morphological characters. The classification is not clearly settled even after several taxonomic revisions and many questions remain, especially about genus Sergentomyia, which is repeatedly mentioned in connection with transmission of mammals' leishmaniasis. This bachelor thesis gives contemporary summary of taxonomic knowledge of sand flies; special attention is given to genus Sergentomyia.
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Comparison of different rodent species as hosts of human pathogenic leishmania.
Vojtková, Barbora ; Sádlová, Jovana (advisor) ; Kodym, Petr (referee) ; Shaw, Jeffrey Jon (referee)
6 ABSTRACT Leishmania parasites (Kinetoplastida: Trypanosomatidae) are causative agents of leishmaniases, a group of vector-borne diseases with various manifestations and complex epidemiology. Principal vectors are sand flies (Diptera: Psychodidae) and among mammalian hosts, rodents are predominantly represented. Rodents are also the most common laboratory models for the research of leishmaniases. However, reservoirs of most Leishmania species are still poorly recognized and the scope of standard model hosts is still insufficient to mimic well the wide spectrum of leishmaniases. This PhD thesis summarizes three different topics, all dealing with experimental infections of rodents with important human parasites - Leishmania major and L. donovani. The first topic was focused on the effect of sand fly saliva on the development of cutaneous leishmaniasis. BALB/c mice infected intradermally with L. major were repeatedly bitten by P. duboscqi females every two weeks. The multiple and repeated sand fly bites significantly enhanced the development of cutaneous lesions and increased parasite load. The second topic was aimed at enrichment of the spectrum of laboratory model animals for Leishmania research. Three Asian rodent species (Cricetulus griseus, Lagurus lagurus and Phodopus sungorus) were infected with L....
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Role of asymptomatic hosts in leishmaniasis transmission.
Sandner, Bruno ; Sádlová, Jovana (advisor) ; Kodym, Petr (referee)
Leishmania parasites have a digenetic-life cycle, circulating between vertebrate hosts and insect vectors, mainly phlebotomine sand flies (Diptera: Phlebotominae). Mammals serve as principal reservoirs of the disease and maintain the leishmania population even in the absence of the vector. Knowledge of the role of asymptomatic hosts in parasite transmission is one of the key prerequisites to understand epidemiology of leishmaniases. The aim of this work is to summarize the studies on asymptomatic hosts of visceral leishmaniasis caused by L. infantum and L. donovani. In L. infantum, asymptomatic hosts have been shown to be involved in transmission, namely dogs, humans, and other putative reservoir hosts. Asymptomatic dogs infect the same proportion of vectors as symptomatic dogs, and in humans, HIV coinfection significantly increased the infectiousness. VL caused by L. donovani is regarded as mostly anthroponotic, but the parasite has been often detected in animal hosts and zoonotic transmission has been suggested in East Africa. Transmission from asymptomatic individuals has not been established, but the studies on this topic are very scarce. Further intensive research is needed to confirm the role of potential reservoir hosts and asymptomatic individuals in the transmission of leishmaniases....
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Diagnosis of leishmaniases in humans and dogs
Černá, Eva ; Spitzová, Tatiana (advisor) ; Votýpka, Jan (referee)
Leishmaniasis is a serious disease caused by parasites that affects both people and animals. In people, this disease has three forms, cutaneous, mucocutaneous and visceral form. Visceral form is lethal if it's left untreated. Leismaniasis is usually diagnosed by using regular parasitological methods based on histocytological analysis. In the last few years, there has been a considerable progress in serological and molecular diagnostics. This thesis focuses on description and comparison of the traditional and the new diagnostic methods. Attention is paid primarily to the new methods, therefore serological and molecular. These methods are compared by their sensitivity, specifity, field application potential, financial costs and time consumption. Both human and canine diagnostics are mentioned due to the fact that dogs are a significant reservoir. Key words leishmaniasis, diagnostics, parasitology, humans, dogs, method, molecular, serological, sensitivity, specifity
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Zoonózy v Peru
Gajdová, Klára
The diploma thesis deals with infectious diseases transmitted from animals to humans. These diseases have a significant impact on public health and the economy around the world, especially in less developed countries. The theoretical part defines the infectious and epidemic process of the disease, including the source of the causative agent and factors that influence the incidence and spread of diseases. The practical part analyzes the situation of the occurrence of endemic diseases occurring in Peru and compares them with the situation in neighboring states using the beta and sigma convergence methods. The results are presented by a correlation diagram. In conclusion, the situation of selected diseases is evaluated and suggestions are made to improve the epidemiological situation and recommendations to those traveling to this country, both for work and study, as well as for tourism.
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Leishmaniases and their vectors in the Middle East
Zelenková, Natálie ; Dvořák, Vít (advisor) ; Votýpka, Jan (referee)
Leishmaniases are vector-borne parasitic diseases that remain major neglected tropical diseases of the world. Both cutaneous and visceral leishmaniasis is endemic in the Middle East, with several countries reporting increasing incidence in recent years. The Middle East is a region of great political instability and the escalating conflicts in Syria, Yemen and Iraq have led to collapses of local healthcare systems. These countries have consequently seen many outbreaks of leishmaniasis. War is associated with refugee crisis that enables further spread of the disease to previously non-endemic areas. L. major and L. tropica are the main causative agents of cutaneous leishmaniasis and species of the L. donovani complex are the causative agents of visceral leishmaniasis in this region. Many species of the genus Phlebotomus occur here, with P. papatasi and P. sergenti being among the most abundant proven local vectors. Rodents and dogs are considered to be the main reservoir hosts of the infection. The aim of this bachelor thesis is to summarize the occurence of leishmaniases in the Middle Eastern countries in the context of the current situation in this region.
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