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Development of Asaia genus in sand flies and its impact on Leishmania transmission
Stejskalová, Markéta ; Jančářová, Magdaléna (advisor) ; Procházková, Petra (referee)
The composition of the microbiome of insect vectors plays an irreplaceable role in the spread of human pathogens. Current knowledge of the interrelationships between phlebo- tomes, bacteria, and pathogens is quite limited. This thesis focuses on bacterias Asaia sp., which can be localized in a phlebotome microbiome. Both investigated species, Asaia siamensis and Asaia krungthepensis, can colo- nize the gut of Phlebotomus duboscqi, and, in addition, both transstadial transmission between larval stages and contaminative transmission to the next generation has been proved. Considering the superinfection of Ph. duboscqi with Asaia sp. and Leishmania major, the influence of bacteria on the development of leishmania infection has also been demonstrated. Results can have significant epidemiological implications and should be further investigated. Keywords: Phlebotomus, superinfection, Asaia siamensis, Asaia krungthepensis, Leishma- nia major, microbiome 1
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Toscana virus development in sand flies
Rehbergerová, Markéta ; Jančářová, Magdaléna (advisor) ; Hönig, Václav (referee)
The Toscana virus (TOSV) is a causative agent of meningitis, meningoencephalitis, and encephalitis in humans. It is transmitted by the hematophagous sand flies Phlebotomus perniciosus and Ph. perfiliewi (Diptera, Psychodidae, Phlebotominae) in the Mediterranean area mainly during the summer months. In this thesis we studied experimental infections of sand flies belonging to species of Ph. papatasi, Ph. perniciosus, Ph. sergenti, Ph. tobbi, and Sergentomyia schwetzi with viral strains of two TOSV lineages (TOSV-A and TOSV-B). We were unable to infect any of the tested sand fly species with TOSV- A via artificial blood feeding. We report the susceptibility of Ph. tobbi and Ph. sergenti to TOSV-B by artificial blood feeding with infection rates of 59.5% and 5.9%, respectively, and the dissemination of the virus to the head with attached salivary glands suggesting the potential for TOSV transmission to vertebrates. Experimental TOSV infections through sugar meals were unsuccessful. Key words: Toscana virus, Phlebovirus, Phlebotominae, sand fly, vector competence
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Critical factors affecting pathogen development in sand flies
Jančářová, Magdaléna ; Volf, Petr (advisor) ; Ratinier, Maxime (referee) ; Bilej, Martin (referee)
This thesis deals with barriers and factors critical for development of viruses, leishmania and gregarines in sand flies. First, we focused on life cycle of sand fly-borne phleboviruses, especially possible routes of sand fly infection. As a laboratory model we chose Massilia virus (MASV), species closely related to Toscana virus, which is main causative agent of summer meningitis in Mediterranean area. We tested different ways of infection by MASV in various developmental stages of Phlebotomus perniciosus; infection of (i) first (L1) and fourth (L4) instar larvae through larval food, (ii) females by blood meal, (iii) both sexes by sugar meal. Infection of L1 and L4 by larval food and subsequent transstadial MASV transmission to adults were not efficient; from 875 adults only three were MASV-positive. Infection through bloodmeal led to high infection rate before defecation, nevertheless, post defecation the infection rate declined and only 5 out of 27 females were MASV-positive. The most efficient infection way was through the sugar meal: 72% of females (88 out of 122) and 51% of males (58 out of 113) were detected as MASV-positive. Moreover, both males and females infected by this way released MASV particles into the drop of sugar which stayed infectious for next 24 hours for other naïve sand...
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Leishmania-gregarine coinfections in sand flies
Jančářová, Magdaléna ; Volf, Petr (advisor) ; Bilej, Martin (referee)
This thesis consists of two related parts; the first one deals with the effect of gregarines Psychodiella sergenti on susceptibility of sand fly Phlebotomus sergenti to experimental infection of Leishmania tropica. Comparison of the Turkish colony of P. sergenti infected by gregarines (TRG) and the Israeli colony noninfected by gregarines (IS) revealed significantly higher intensity of L. tropica infection in TRG colony on days 2 and 10 after the infective bloodmeal. In addition, in TRG colony leishmania promastigotes significantly faster colonised the stomodeal valve. However, these differences seems to be caused not due to the presence of gregarines but due to intraspecific genetic variability of P. sergenti or different composition of gut microbiota in both colonies. In two colonies of P. sergenti originally from Israel, one infected by gregarines (ISG) and the second noninfected (IS), no significant difference was found. ISG and IS colonies did not differ in the percentage of infected females, the intensity of infection and the localization of L. tropica promastigotes. In the second part of my thesis, degenerated primers designed on the basis of sequences of immune molecules of Phlebotomus papatasi and Lutzomyia longipalpis and subsequent cloning of products by means of pGEM®-T Easy Vector...
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Critical factors affecting pathogen development in sand flies
Jančářová, Magdaléna
This thesis deals with barriers and factors critical for development of viruses, leishmania and gregarines in sand flies. First, we focused on life cycle of sand fly-borne phleboviruses, especially possible routes of sand fly infection. As a laboratory model we chose Massilia virus (MASV), species closely related to Toscana virus, which is main causative agent of summer meningitis in Mediterranean area. We tested different ways of infection by MASV in various developmental stages of Phlebotomus perniciosus; infection of (i) first (L1) and fourth (L4) instar larvae through larval food, (ii) females by blood meal, (iii) both sexes by sugar meal. Infection of L1 and L4 by larval food and subsequent transstadial MASV transmission to adults were not efficient; from 875 adults only three were MASV-positive. Infection through bloodmeal led to high infection rate before defecation, nevertheless, post defecation the infection rate declined and only 5 out of 27 females were MASV-positive. The most efficient infection way was through the sugar meal: 72% of females (88 out of 122) and 51% of males (58 out of 113) were detected as MASV-positive. Moreover, both males and females infected by this way released MASV particles into the drop of sugar which stayed infectious for next 24 hours for other naïve sand...
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Symbiotic bacteria of the genus Wolbachia in sand flies and mosquitoes.
Rehbergerová, Markéta ; Dvořák, Vít (advisor) ; Jančářová, Magdaléna (referee)
Bacteria of the genus Wolbachia (Proteobacteria, Rickettsiales, Rickettsiaceae) are maternally inherited intracellular symbionts of many species of arthropods (Arthropoda) and filarial nematodes (Nematoda, Secernentea). Due to the ability of Wolbachia to induce reproductive anomalies in their hosts and to reduce their infection by pathogenic organisms and viruses, they are profoundly studied. This bachelor thesis is a summary of available information regarding interactions of Wolbachia with mosquitoes (Diptera, Culicidae) and sand flies (Diptera, Psychodidae, Phlebotominae), vectors of many important infectious pathogens, and possibilities of their use in the control of pathogen transmission. Key words: Wolbachia, Phlebotominae, Culicidae, vector-borne diseases, symbiosis, vector control method
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Critical factors affecting pathogen development in sand flies
Jančářová, Magdaléna
This thesis deals with barriers and factors critical for development of viruses, leishmania and gregarines in sand flies. First, we focused on life cycle of sand fly-borne phleboviruses, especially possible routes of sand fly infection. As a laboratory model we chose Massilia virus (MASV), species closely related to Toscana virus, which is main causative agent of summer meningitis in Mediterranean area. We tested different ways of infection by MASV in various developmental stages of Phlebotomus perniciosus; infection of (i) first (L1) and fourth (L4) instar larvae through larval food, (ii) females by blood meal, (iii) both sexes by sugar meal. Infection of L1 and L4 by larval food and subsequent transstadial MASV transmission to adults were not efficient; from 875 adults only three were MASV-positive. Infection through bloodmeal led to high infection rate before defecation, nevertheless, post defecation the infection rate declined and only 5 out of 27 females were MASV-positive. The most efficient infection way was through the sugar meal: 72% of females (88 out of 122) and 51% of males (58 out of 113) were detected as MASV-positive. Moreover, both males and females infected by this way released MASV particles into the drop of sugar which stayed infectious for next 24 hours for other naïve sand...
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Critical factors affecting pathogen development in sand flies
Jančářová, Magdaléna ; Volf, Petr (advisor) ; Ratinier, Maxime (referee) ; Bilej, Martin (referee)
This thesis deals with barriers and factors critical for development of viruses, leishmania and gregarines in sand flies. First, we focused on life cycle of sand fly-borne phleboviruses, especially possible routes of sand fly infection. As a laboratory model we chose Massilia virus (MASV), species closely related to Toscana virus, which is main causative agent of summer meningitis in Mediterranean area. We tested different ways of infection by MASV in various developmental stages of Phlebotomus perniciosus; infection of (i) first (L1) and fourth (L4) instar larvae through larval food, (ii) females by blood meal, (iii) both sexes by sugar meal. Infection of L1 and L4 by larval food and subsequent transstadial MASV transmission to adults were not efficient; from 875 adults only three were MASV-positive. Infection through bloodmeal led to high infection rate before defecation, nevertheless, post defecation the infection rate declined and only 5 out of 27 females were MASV-positive. The most efficient infection way was through the sugar meal: 72% of females (88 out of 122) and 51% of males (58 out of 113) were detected as MASV-positive. Moreover, both males and females infected by this way released MASV particles into the drop of sugar which stayed infectious for next 24 hours for other naïve sand...
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Microbiota and protists in the gut of sand flies and mosquitoes
Sovová, Kristina ; Volf, Petr (advisor) ; Jančářová, Magdaléna (referee)
Sand flies and mosquitoes are vectors of leishmania and plasmodium, which are parasitic protists, that cause malaria and leishmaniasis. Mosquitoes and sand flies are exposed to a wide range of micro-organisms, which enter their bodies when they get in contact with the surrounding environment, when they intake food or via a transfer from individual to individual.The larvae acquire micro-organisms from breeding sites microhabitat, the adults from the sugary food and blood. The vast majority of the bacteria found in the mesenteron of adult vectors belongs to a group of gram negative. During the larval stages, however, the ratio of gram positive bacteria in the gut increases. In the gut, the bacteria can encounter parasitic protists and influence their development, directly or indirectly. Direct influence can be caused, for example, by the production of secondary bacterial metabolites. Indirectly, the bacteria can modulate the vector's competence over its immune system. Key words: Phlebotomus, Lutzomyia, Leishmania, microbiom
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Leishmania-gregarine coinfections in sand flies
Jančářová, Magdaléna ; Volf, Petr (advisor) ; Bilej, Martin (referee)
This thesis consists of two related parts; the first one deals with the effect of gregarines Psychodiella sergenti on susceptibility of sand fly Phlebotomus sergenti to experimental infection of Leishmania tropica. Comparison of the Turkish colony of P. sergenti infected by gregarines (TRG) and the Israeli colony noninfected by gregarines (IS) revealed significantly higher intensity of L. tropica infection in TRG colony on days 2 and 10 after the infective bloodmeal. In addition, in TRG colony leishmania promastigotes significantly faster colonised the stomodeal valve. However, these differences seems to be caused not due to the presence of gregarines but due to intraspecific genetic variability of P. sergenti or different composition of gut microbiota in both colonies. In two colonies of P. sergenti originally from Israel, one infected by gregarines (ISG) and the second noninfected (IS), no significant difference was found. ISG and IS colonies did not differ in the percentage of infected females, the intensity of infection and the localization of L. tropica promastigotes. In the second part of my thesis, degenerated primers designed on the basis of sequences of immune molecules of Phlebotomus papatasi and Lutzomyia longipalpis and subsequent cloning of products by means of pGEM®-T Easy Vector...
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