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Trypanosomes transmitted by mosquitoes: occurrence in hosts, transmission, and specificity
Kulich Fialová, Magdaléna ; Svobodová, Milena (advisor) ; Bernotienė, Rasa (referee) ; Modrý, David (referee)
7 Abstract Trypanosomes (Trypanosoma, Kinetoplastea) are dixenous blood protists that require not only a vertebrate host but also a blood-feeding invertebrate to complete their life cycle. Infection of vertebrates can be asymptomatic, but on the other hand can cause serious diseases affecting lives of humans and animals. Thus, researchers usually focus on Trypanosoma species causing Chagas disease and sleeping sickness in humans or nagana and surra in animals, and on their vectors: tsetse flies and kissing bugs. However, mosquitoes are able to transmit trypanosomes as well, specifically, avian trypanosomes and probably mammalian trypanosomes from the T. theileri group. Nevertheless, the role of mosquitoes in the life cycle of trypanosomes has substantial gaps, which are focused in this dissertation. Within the experimental work, it has been demonstrated that mosquitoes of the genus Culex are susceptible hosts of two species of avian trypanosomes: T. thomasbancrofti and T. tertium n. sp. On the other hand, Culex mosquitoes were unsuitable hosts for T. theileri, while the genus Aedes and surprisingly even sand flies (Phlebotomus perniciosus) turned up to be competent vectors. All investigated trypanosomes were able to develop within the guts of mosquitoes and were also found in their prediuretic liquid. This...
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Influence of avian Plasmodium on their hosts
Dulavová, Kristýna ; Svobodová, Milena (advisor) ; Vinkler, Michal (referee)
Avian malaria parasites of the genus Plasmodium are unicellular (and intracellular) protozoans of the group Haemospororida, using a blood-sucking insect (mosquito) as a vector and a bird as a vertebrate host. The effects of this disease, together with avian pox, have greatly influenced endemic populations of Hawaiian birds after introduction of a suitable vector to the islands by a human hand, leading to a drastic extinction of bird species; most of the remaining Hawaiian endemic species are now endangered. Apart from that, avian malaria is distributed nearly all over the world, infecting a variety of different hosts. This thesis is focused on the influence of avian malaria parasites mainly on their avian hosts. The most severe patologies caused by Plasmodium are associated with blood stages causing serious anemia in birds. More pathologies are connected with exoerythrocytic stages in the endothelial cells in various organs and are accompanied with external signs such as lethargy, respiratory distress, weakness, inappetence, sometimes weight loss and so on; different plasmodium species-bird host combinations have different outcomes. An interesting issue is the emerging tolerance against avian malaria in Hawaii Amakihi (Hemignathus virens), a species occupying low elevation areas of Hawaiian...
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Mosquito bloodmeal and its effect on fecundity and protozoan parasite transmission
Karafiátová, Aneta ; Svobodová, Milena (advisor) ; Leipnerová, Zdeňka (referee)
Mosquitoes are widespread insects known for their ability to spread pathogens (protozoans, viruses, bacteria, helminths) that are the causing agents of diseases resulting in more than a million deaths annually. These vectors feed on different animal species, however, some genera have preference for mammals or birds. The goal of this thesis was to answer questions focusing on the bloodmeal of the mosquito: whether different species have different host preferences, whether the ingested bloodmeal has an effect on the fecundity of the female mosquito and whether there are differences in fecundity when ingesting bloodmeal from different hosts (mammal, bird, amphibian etc.), and, lastly, whether the bloodmeal might have an effect on the development and transmission of parasitic protozoans. Key words: host, mosquito, vector, blood, host preference, fecundity, transmission
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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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The role of hippoboscids in avian trypanosomes transmission
Santolíková, Anežka ; Svobodová, Milena (advisor) ; Dvořák, Vít (referee)
The aim of this thesis was to map the presence of avian hippoboscids in Czechia, clarify which lineages of avian trypanosomes are transmitted by them, and to test vector specificity of the trypanosomes that were isolated from louse flies earlier. In the years 2017 - 2018 we found 7 species of louse flies, namely Ornithomya avicularia (91), O. biloba (267), O. fringillina (45), Ornithoica turdi (6), Stenepteryx hirundinis (1) and Ornithophila metallica (1). The specificity of O. biloba and S. hirundinis toward Hirudinidae was confirmed. The other louse fly species were found on both migrant and resident birds. The phylogenetic analysis of gene for cytochrome c oxidase I which contained a newly characterised species O. metallica revealed that it is related to O. turdi. Avian trypanosomes were present in the following species: O. biloba (prevalence 20 %), O. avicularia (8 %), a O. fringillina (4 %). All trypanosome sequences from hippoboscids belonged to the avian trypanosome group corvi-culicavium. Phylogenetic analysis of trypanosome sequences confirmed the presence of five lineages of avian trypanosomes. Four trypanosome sequences from birds formed two new basal clades. Most of the trypanosome sequences from hippoboscids formed a sister group to the previously described lineages. The vector specificity of...
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Mosquitoes as vectors of avian trypanosomes
Fialová, Magdaléna ; Svobodová, Milena (advisor) ; Šlapeta, Jan (referee)
Avian trypanosomes are quite common parasites of birds, although knowledge of their life cycles and vectors is still insufficient. There are some insect families which serve as vectors of these parasites: blackflies (Simuliidae), hippoboscid flies (Hippobosciade), mosquitoes (Culicidae), biting midges (Ceratopognidae) and sandflies (Psychodidae). In this study we have been focused on mosquitoes. We have examined prevalence of avian trypanosomes at wild-caught mosquitoes from genus Culex. Furthermore we have studied experimental transmission of avian trypanosomes from mosquitoes to birds. Mosquitoes were caught with CDC traps in three different localities during seasons 2017 and 2018. We caught 956 (125 pools) mosquitoes belonging to genus Culex, from whom 14,4 % pools were positive for avian trypanosomes. MIR (Minimal Infectiom Rate) fluctuated between 0 % to 8,3 % in studied months (May-August). The most frequently identified parasite was T.culicavium, detected in 13,6% (n=17) pooles. Parasites belonging to T. avium group were detected only in 0,8 % (n=1), it was T. thomasbancrofti. In our experimental part we have been focused on development of T. thomasbancrofti and Trypanosoma sp. in laboratory bred mosquitoes Cx. quinquefasciatus and Cx. molestus and on their experimental transmission to...
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Haemoproteus in passerines: Prevalence and infekction dynamics
Chalupová, Barbora ; Svobodová, Milena (advisor) ; Munclinger, Pavel (referee)
The genera Haemoproteus and Plasmodium are widespread genera of blood parasites from phylum Apicomplexa. Both genera have dixenous life cycle and their definitive hosts belong to the order Diptera. Both parasites can be found in birds where asexual division takes place. The infection with genera Haemoproteus and Plasmodium is usually asymptomatic; during long lasting chronic phase relapses of the infection can occur. We gained 1 092 blood samples from 29 trapped species of passerines in Milovice forest during seasons 2017-2019. Haemosporidians were detected in 48 % of samples. The prevalence of genus Plasmodium was 16 %, the prevalence of genus Haemoproteus was 22 % and 10 % we could not specify the parasite. We have found six new lineages of genus Haemoproteus, provisionally named Haemoproteus lineages coccoc_1, coccoc_2, coccoc_3, coccoc_4, embcit, fricoe which total prevalence was 14 %. Lineage Haemoproteus sp. coccoc_1 was the most noticed one and its prevalence was 12 %. Plasmodium relictum clone Peng14-121Br2AF and isolate Cc_P1 was the second most prevalent (13 %). Infection dynamics was studied in samples gained in years 2014-2019. Forty individuals were examined between years and twenty-seven individuals were examined intraseasonally. Three individuals were trapped both intra- and...
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