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The role of Toxoplasma gondii in human infertility - host manipulation or a side effect of the disease
Hlaváčová, Jana
Approximately one-third of the world's population is infected with the parasitic protozoan Toxoplasma gondii (T. gondii). Besides the classical sources of infection, sexual transmission of the parasite has recently been discussed and confirmed in many animal species. However, only indirect evidence supports this mode of transmission in humans. Our study found that Toxoplasma-seropositivity of sexual partner was a risk factor for T. gondii infection in women. These results supported the hypothesis of unidirectional male-to-female sexual transmission. We further proposed the hypothesis of T. gondii transmission during oral sex when an uninfected individual ingests the ejaculate of an infected man. If the ejaculate contained tissue cysts of the parasite, a mode of infection similar to ingesting the parasite in raw meat would be expected. To determine whether T. gondii is indeed present in the semen of men, we subsequently conducted a study in which we were the first to demonstrate the presence of tissue cysts of the parasite in the semen of men with latent toxoplasmosis. The impact of toxoplasmosis was also investigated in relation to reproductive functions. A higher prevalence of toxoplasmosis was found in infertile men compared to controls. In our study, we found that latent toxoplasmosis negatively...
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The role of Toxoplasma gondii in human infertility - host manipulation or a side effect of the disease
Hlaváčová, Jana ; Kaňková, Šárka (advisor) ; Kodym, Petr (referee) ; Fajfrlík, Karel (referee)
Approximately one-third of the world's population is infected with the parasitic protozoan Toxoplasma gondii (T. gondii). Besides the classical sources of infection, sexual transmission of the parasite has recently been discussed and confirmed in many animal species. However, only indirect evidence supports this mode of transmission in humans. Our study found that Toxoplasma-seropositivity of sexual partner was a risk factor for T. gondii infection in women. These results supported the hypothesis of unidirectional male-to-female sexual transmission. We further proposed the hypothesis of T. gondii transmission during oral sex when an uninfected individual ingests the ejaculate of an infected man. If the ejaculate contained tissue cysts of the parasite, a mode of infection similar to ingesting the parasite in raw meat would be expected. To determine whether T. gondii is indeed present in the semen of men, we subsequently conducted a study in which we were the first to demonstrate the presence of tissue cysts of the parasite in the semen of men with latent toxoplasmosis. The impact of toxoplasmosis was also investigated in relation to reproductive functions. A higher prevalence of toxoplasmosis was found in infertile men compared to controls. In our study, we found that latent toxoplasmosis negatively...
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Effect of abiotic and biotic factors on Leishmania development in sand fly vectors
Hlaváčová, Jana ; Volf, Petr (advisor) ; Alten, Bülent (referee) ; Traub-Cseko, Yara Maria (referee)
The thesis deals with Leishmania development in sand flies focusing on factors that could affect the vectorial part of their lifecycle. First, we examined an effect of temperature on Leishmania development in sand flies since the global warming was suggested to be one of the most important factors affecting dissemination of leishmaniasis. Development of three Leishmania species were studied at two different temperatures (20 and 26řC); L. infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus, and two closely related Viannia species L. braziliensis and L. peruviana in Lu. longipalpis. Leishmania peruviana thrived well only at the lower temperature tested. At the higher temperature, most of infections were lost between days 2 and 8 post feeding, i.e. time of blood-meal remnants defecation. This suggests that this Andean species is adapted to slower metabolism of vectors living at lower temperatures. On the other hand, L. infantum and L. braziliensis successfully developed in sand flies at both temperatures tested, which might be substantial for their further spread to new areas. Next, an impact of gregarine Psychodiella sergenti on L. tropica in Phlebotomus sergenti was studied. Gregarines are commonly found in sand flies, and in mosquitoes, they can affect development of other...
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Viannia development in the vector
Hlaváčová, Jana ; Volf, Petr (advisor) ; Dostálová, Anna (referee)
Leishmania of the subgenus Viannia are protozoan parasites transmitted by phlebotomine sandflies (Diptera: Phlebotominae). They occur in tropical and subtropical areas in South America, where they cause cutaneous and mucocutaneous leishmaniasis. In this thesis, we studied developmental pattern of Viannia group and factors affecting its development within the sand fly gut. First, we investigated Leishmania braziliensis development within the Lutzomyia longipalpis digestive tract. Using GFP-labeled strain we demonstrated peripylar development: promastigotes escaped from the endoperitrophic space, colonized the hindgut and then migrated anteriorly. Four morphological forms were found within the Lu. longipalpis digestive tract: elongated nectomonads, short nectomonads, metacyclic promastigotes and paramastigotes. Furthermore, using the histological methods we demonstrated parasite attachment in pylorus region, while there were only free promastigotes in the midgut; neither form was found attached to the midgut epithelium. The next part was devoted to the effect of temperature on Viannia in Lu. longipalpis. We compared development of two closely related species L. peruviana and L. braziliensis at 20 řC and 26 řC. Leishmania braziliensis developed well in both temperatures tested, L. peruviana developed...
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Effect of abiotic and biotic factors on Leishmania development in sand fly vectors
Hlaváčová, Jana
The thesis deals with Leishmania development in sand flies focusing on factors that could affect the vectorial part of their lifecycle. First, we examined an effect of temperature on Leishmania development in sand flies since the global warming was suggested to be one of the most important factors affecting dissemination of leishmaniasis. Development of three Leishmania species were studied at two different temperatures (20 and 26řC); L. infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus, and two closely related Viannia species L. braziliensis and L. peruviana in Lu. longipalpis. Leishmania peruviana thrived well only at the lower temperature tested. At the higher temperature, most of infections were lost between days 2 and 8 post feeding, i.e. time of blood-meal remnants defecation. This suggests that this Andean species is adapted to slower metabolism of vectors living at lower temperatures. On the other hand, L. infantum and L. braziliensis successfully developed in sand flies at both temperatures tested, which might be substantial for their further spread to new areas. Next, an impact of gregarine Psychodiella sergenti on L. tropica in Phlebotomus sergenti was studied. Gregarines are commonly found in sand flies, and in mosquitoes, they can affect development of other...
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Influence of latent toxoplasmosis on human fertility
Hlaváčová, Jana ; Kaňková, Šárka (advisor) ; Calda, Pavel (referee)
Toxoplasma gondii is one of the most widespread parasitic protozoa in humans in developed countries. It has a wide range of hosts including various warm-blooded animals and humans. Recent studies suggest that it could influence the fertility of humans. The aim of this work was to find out, what is the prevalence of toxoplasmosis in groups of women and men with fertility problems and whether Toxoplasma gondii has an effect on specific fertility parameters. In women, Significant positive correlation between toxoplasmosis and the percentage of oocytes in the follicles was found among women. Group of men with semen pathology diagnosis revealed a statistically significant negative association between toxoplasmosis and the percentage of morphologically normal sperm. It seems that latent toxoplasmosis in men can also worsen the negative effect of tobacco smoking on fertility. The impairment of fertility in men could be the result of the manipulation activity of Toxoplasma gondii, which leads to more frequent sexual intercourse due to decreased ability to conceive. This could increase the likelihood of sexual transmission, which is currently suggested as one of the possible ways of transmission of toxoplasmosis.
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Effect of abiotic and biotic factors on Leishmania development in sand fly vectors
Hlaváčová, Jana ; Volf, Petr (advisor) ; Alten, Bülent (referee) ; Traub-Cseko, Yara Maria (referee)
The thesis deals with Leishmania development in sand flies focusing on factors that could affect the vectorial part of their lifecycle. First, we examined an effect of temperature on Leishmania development in sand flies since the global warming was suggested to be one of the most important factors affecting dissemination of leishmaniasis. Development of three Leishmania species were studied at two different temperatures (20 and 26řC); L. infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus, and two closely related Viannia species L. braziliensis and L. peruviana in Lu. longipalpis. Leishmania peruviana thrived well only at the lower temperature tested. At the higher temperature, most of infections were lost between days 2 and 8 post feeding, i.e. time of blood-meal remnants defecation. This suggests that this Andean species is adapted to slower metabolism of vectors living at lower temperatures. On the other hand, L. infantum and L. braziliensis successfully developed in sand flies at both temperatures tested, which might be substantial for their further spread to new areas. Next, an impact of gregarine Psychodiella sergenti on L. tropica in Phlebotomus sergenti was studied. Gregarines are commonly found in sand flies, and in mosquitoes, they can affect development of other...
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Effect of abiotic and biotic factors on Leishmania development in sand fly vectors
Hlaváčová, Jana
The thesis deals with Leishmania development in sand flies focusing on factors that could affect the vectorial part of their lifecycle. First, we examined an effect of temperature on Leishmania development in sand flies since the global warming was suggested to be one of the most important factors affecting dissemination of leishmaniasis. Development of three Leishmania species were studied at two different temperatures (20 and 26řC); L. infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus, and two closely related Viannia species L. braziliensis and L. peruviana in Lu. longipalpis. Leishmania peruviana thrived well only at the lower temperature tested. At the higher temperature, most of infections were lost between days 2 and 8 post feeding, i.e. time of blood-meal remnants defecation. This suggests that this Andean species is adapted to slower metabolism of vectors living at lower temperatures. On the other hand, L. infantum and L. braziliensis successfully developed in sand flies at both temperatures tested, which might be substantial for their further spread to new areas. Next, an impact of gregarine Psychodiella sergenti on L. tropica in Phlebotomus sergenti was studied. Gregarines are commonly found in sand flies, and in mosquitoes, they can affect development of other...
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Toxoplasma and Host's Reproductive Function
Hlaváčová, Jana ; Kaňková, Šárka (advisor) ; Kodym, Petr (referee)
Toxoplasma gondii (Apicomplexa) is probably one of the most common human parasite in developed countries. It has a wide range of hosts including a variety of warm-blooded animals as well as humans. In this bachelor thesis you can find review of literature focusing on an influence of T. gondii on host's reproductive functions. Toxoplasmosis is accompanied by hormonal changes which may be one reason for the negative effect on host's fertility. Throughout the thesis are mentioned immunosuppression and reduced quality control of embryos associated with T. gondii. Both of these phenomena probably affect pregnancy, prenatal and postnatal development of the offsprings of mothers with latent toxoplasmosis. And these also play a role in shifting of sex ratio in infected hosts.
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