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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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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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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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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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Leishmaniases of northern Africa and their vectors
Hanušniaková, Ida ; Dvořák, Vít (advisor) ; Sádlová, Jovana (referee)
Leishmaniasis belongs to the most important world human as well as animal diseases. It occurs in almost all continents. Its nearest area of occurrence from our point of view is the Mediterranean, including the states of North Africa. A significant portion of all registered cases occurs here and the prevalence has been increasing in last decades. Algeria is the second in the world in number of cases of cutaneous leishmaniasis and in the other countries the situation is quite similar. Two major forms of the disease occur in the region: visceral and cutaneous leishmaniasis. Leishmania major is the most abundant species in the are, followed by L. infantum and L. tropica. In the Old World, leishmanises are transmitted by sand flies of the genus Phlebotomus. The most important proven vectors are Phlebotomus papatasi, P. sergenti, P. perfiliewi or P. perniciosus. Rodents are considered to be main reservoir organisms (Psammomys obesus, Meriones shawi), together with dogs in which canine leishmaniasis may occur with clinical symptoms; at the same time they serve as reservoirs of the disease. This bachelor thesis summarizes occurrence of individual Leishmania species, clinical symptoms they cause in the hosts and their vectors in North Africa. Key words: leishmaniasis, phlebotomus, North Africa, Leishmania,...
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