vector competence
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Zika virus (ZIKV) has spread in the Americas since 2015 and the potential establishment of a sylvatic transmission cycle in the continent has been hypothesized. We evaluated vector competence of five sylvatic Neotropical mosquito species to two ZIKV isolates. Distinct batches of Haemagogus leucoceleanus, Sabethes albiprivus, Sabethes identicus, Aedes terrens and Aedes scapularis females were respectively orally challenged and inoculated intrathoracically with ZIKV. Orally challenged mosquitoes were refractory or exhibited low infection rates. Viral dissemination was detected only in Hg. leucocelaenus, but with very low rates. Virus was not detected in saliva of any mosquito orally challenged with ZIKV, regardless of viral isolate and incubation time. When intrathoracically injected, ZIKV disseminated in high rates in Hg. leucocelaenus, Sa. identicus and Sa. albpiprivus, but low transmission was detected in these species; very low dissemination and no transmission was detected in Ae. terrens and Ae. scapularis. Together these results suggest that genetically determined tissue barriers, especially in the midgut, play a vital role in inhibiting ZIKV for transmission in the tested sylvatic mosquito species. Thus, an independent enzootic transmission cycle for ZIKV in South America is very unlikely.
- MeSH
- infekce přenášené vektorem MeSH
- infekce virem zika diagnóza epidemiologie přenos virologie MeSH
- komáří přenašeči virologie MeSH
- lidé MeSH
- ochrana veřejného zdraví MeSH
- virová nálož MeSH
- virus zika * klasifikace genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Jižní Amerika MeSH
Biting midges of the genus Forcipomyia (Diptera: Ceratopogonidae) have recently been implicated as vectors of kinetoplastid parasites in the Leishmania enrietti complex. This study assesses susceptibility of one of the few successfully colonized Ceratopogonidae, Culicoides nubeculosus Meigen, to infection with Leishmania parasites infecting humans. While Leishmania infantum initially developed in the midgut of C. nubeculosus until 2 d postfeeding, parasite populations on day 3 were considerably reduced. Despite this, a polymerase chain reaction-based assay continued to indicate presence of L. infantum for up to 7 d after the bloodmeal. These findings are discussed within the wider context of implicating arthropods as vectors of Leishmania and it is suggested that conventional polymerase chain reaction use in vector-competence studies should be accompanied by direct microscopical observations.
- MeSH
- feces parazitologie MeSH
- finanční podpora výzkumu jako téma MeSH
- hmyz - vektory parazitologie MeSH
- králíci MeSH
- Leishmania major izolace a purifikace růst a vývoj MeSH
- Leishmania tropica izolace a purifikace růst a vývoj MeSH
- Phlebotomus parazitologie MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
A prerequisite for possible autochthonous transmission of the Zika virus in Europe would be the presence of a competent mosquito species of the genus Aedes. The Aedes aegypti mosquito has been recognized worldwide as a Zika virus vector, and the Asian tiger mosquito (Aedes albopictus) is considered as a potential alternative vector. In Europe, Aedes aegypti is only present on the Madeira island and locally along the east coast of the Black Sea. However, Aedes albopictus is abundant in nearly all Mediterranean countries, southern Switzerland, and in the Balkans. The key question is as follows: Are the European populations of Aedes albopictus competent for Zika virus transmission?
Pro případný autochtonní přenos viru Zika v Evropském regionu je nutná přítomnost kompetentního komářího přenašeče (vektor) rodu Aedes. Celosvětově je komár tropický (Aedes aegypti) prokázaný přenašeč viru Zika, komár tygrovaný (Aedes albopictus) je považován za pravděpodobného alternativního přenašeče. Výskyt Ae. aegypti v Evropě je omezen na ostrov Madeira a okrskově na východní pobřeží Černého moře. Avšak Ae. albopictus se vyskytuje, mnohdy velmi hojně, prakticky ve všech středomořských státech, v jižním Švýcarsku a na Balkáně. Klíčová otázka zní: jsou evropské populace Ae. albopictus schopny přenést virus Zika?
- Klíčová slova
- komár tropický, komár tygrovaný, Aedes aegypti, Aedes albopictus,
- MeSH
- Aedes * MeSH
- Flaviviridae * MeSH
- hmyz - vektory * MeSH
- infekce viry z čeledi Flaviviridae přenos MeSH
- virus zika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Geografické názvy
- Evropa MeSH
Visceral leishmaniasis (VL), the most severe form of the disease, is caused by Leishmania donovani in the Indian sub-continent (ISC). Whole genome sequencing studies revealed that two parasite populations exist in the ISC: a main population named the Core Group (CG) found mostly in the lowlands, and a new, genetically different subpopulation called ISC1. Parasites belonging to the CG were shown to be responsible for the recent epidemics, while the ISC1 variant was originally identified in hilly districts of Nepal and was later on increasingly found in the lowlands. Importantly, the ISC1 and CG isolates differ in their drug susceptibility and virulence signatures, suggesting that ISC1 constitutes an emerging and functionally different variant of L. donovani. In present study we aimed to address the potential of ISC1 transmission by the natural vector of L. donovani in the lowlands, Phlebotomus argentipes. By experimental infection of sand flies with parasites of the different genotypes, we demonstrate that ISC1 and CG strains are developing similarly in P. argentipes, suggesting that P. argentipes is a fully competent vector for ISC1 parasites. Integration of previous and current findings shows thus that ISC1 is a new and different variant of L. donovani, fully adapted to spread in the ISC through the main vector. This information is directly useful for managers of the elimination program. Furthermore, integration of our successive studies (genotyping, phenotyping and vector competence) demonstrates the relevance of molecular surveillance and should be of interest for scientists working on vector borne diseases and control managers.
- MeSH
- fylogeneze MeSH
- hmyz - vektory parazitologie MeSH
- Leishmania donovani klasifikace genetika izolace a purifikace MeSH
- leishmanióza viscerální přenos MeSH
- lidé MeSH
- Phlebotomus parazitologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Indie MeSH
BACKGROUND: Leishmania infantum is the most widespread etiological agent of visceral leishmaniasis (VL) in the world, with significant mortality rates in human cases. In Latin America, this parasite is primarily transmitted by Lutzomyia longipalpis, but the role of Lutzomyia migonei as a potential vector for this protozoan has been discussed. Laboratory and field investigations have contributed to this hypothesis; however, proof of the vector competence of L. migonei has not yet been provided. In this study, we evaluate for the first time the susceptibility of L. migonei to L. infantum. METHODS: Females of laboratory-reared L. migonei were fed through a chick-skin membrane on rabbit blood containing L. infantum promastigotes, dissected at 1, 5 and 8 days post-infection (PI) and checked microscopically for the presence, intensity and localisation of Leishmania infections. In addition, morphometric analysis of L. infantum promastigotes was performed. RESULTS: High infection rates of both L. infantum strains tested were observed in L. migonei, with colonisation of the stomodeal valve already on day 5 PI. At the late-stage infection, most L. migonei females had their cardia and stomodeal valve colonised by high numbers of parasites, and no significant differences were found compared to the development in L. longipalpis. Metacyclic forms were found in all parasite-vector combinations since day 5 PI. CONCLUSIONS: We propose that Lutzomyia migonei belongs to sand fly species permissive to various Leishmania spp. Here we demonstrate that L. migonei is highly susceptible to the development of L. infantum. This, together with its known anthropophily, abundance in VL foci and natural infection by L. infantum, constitute important evidence that L. migonei is another vector of this parasite in Latin America.
Ticks and the pathogens they transmit constitute a growing burden for human and animal health worldwide. Vector competence is a component of vectorial capacity and depends on genetic determinants affecting the ability of a vector to transmit a pathogen. These determinants affect traits such as tick-host-pathogen and susceptibility to pathogen infection. Therefore, the elucidation of the mechanisms involved in tick-pathogen interactions that affect vector competence is essential for the identification of molecular drivers for tick-borne diseases. In this review, we provide a comprehensive overview of tick-pathogen molecular interactions for bacteria, viruses, and protozoa affecting human and animal health. Additionally, the impact of tick microbiome on these interactions was considered. Results show that different pathogens evolved similar strategies such as manipulation of the immune response to infect vectors and facilitate multiplication and transmission. Furthermore, some of these strategies may be used by pathogens to infect both tick and mammalian hosts. Identification of interactions that promote tick survival, spread, and pathogen transmission provides the opportunity to disrupt these interactions and lead to a reduction in tick burden and the prevalence of tick-borne diseases. Targeting some of the similar mechanisms used by the pathogens for infection and transmission by ticks may assist in development of preventative strategies against multiple tick-borne diseases.
- MeSH
- arachnida jako vektory mikrobiologie parazitologie virologie MeSH
- interakce hostitele a patogenu * MeSH
- klíšťata mikrobiologie parazitologie fyziologie virologie MeSH
- lidé MeSH
- nemoci přenášené klíšťaty epidemiologie MeSH
- přenos infekční nemoci * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
BACKGROUND: Sand fly species of the genus Sergentomyia are proven vectors of reptilian Leishmania that are non-pathogenic to humans. However, a consideration of the role of Sergentomyia spp. in the circulation of mammalian leishmaniasis appears repeatedly in the literature and the possibility of Leishmania transmission to humans remains unclear. Here we studied the susceptibility of colonized Sergentomyia schwetzi to Leishmania donovani and two other Leishmania species pathogenic to humans: L. infantum and L. major. METHODS: Females of laboratory-reared S. schwetzi were infected by cultured Leishmania spp. by feeding through a chicken membrane, dissected at different time intervals post bloodmeal and examined by light microscopy for the abundance and location of infections. RESULTS: All three Leishmania species produced heavy late stage infections in Lutzomyia longipalpis or Phlebotomus duboscqi sand flies used as positive controls. In contrast, none of them completed their developmental cycle in Sergentomyia females; Leishmania promastigotes developed within the bloodmeal enclosed by the peritrophic matrix (PM) but were defecated together with the blood remnants, failing to establish a midgut infection. In S. schwetzi, the PM persisted significantly longer than in L. longipalpis and it was degraded almost simultaneously with defecation. Therefore, Leishmania transformation from procyclic to long nectomonad forms was delayed and parasites did not attach to the midgut epithelium. CONCLUSIONS: Sergentomyia schwetzi is refractory to human Leishmania species and the data indicate that the crucial aspect of the refractoriness is the relative timing of defecation versus PM degradation.
- MeSH
- hmyz - vektory parazitologie MeSH
- Leishmania donovani růst a vývoj patogenita fyziologie MeSH
- leishmanióza viscerální parazitologie přenos MeSH
- lidé MeSH
- Psychodidae parazitologie MeSH
- virulence MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Recombinant vaccinia viruses (rVACV) expressing various tumor-associated antigens have been shown to elicit anti-tumor effect in numerous experimental models and clinical trials. We tested the hypotheses that rVACV expressing biologically active fms-like tyrosine kinase 3 ligand (Flt3L) would show higher immunogenicity than control viruses expressing only model antigen and that coexpression of Flt3L would influence anti-tumor activity of rVACV in the preventive and therapeutic arrangements of the in vivo experiment. To answer these questions, we took advantage of the well-described model of transplanted tumor cells expressing HPV16 E6 and E7 oncoproteins. To determine the effects of hFlt3L on the induction of anti-tumor immunity, we generated live vaccinia viruses that express human Flt3L regulated by the early H5 or strong synthetic E/L promoter together with fusion protein SigE7LAMP, which is a highly immunogenic form of HPV E7 oncoprotein. We tested Flt3L production in vitro and in vivo. Despite higher expression of Flt3L from the synthetic E/L promoter in vitro, the P13-E/L-FL-SigE7LAMP induced lower levels of Flt3L in the serum of mice than P13-H5-FL-SigE7LAMP. The Flt3L expression under the strong early VACV H5 promoter is able to inhibit expansion of CD11b+Gr-1+ myeloid suppressor cells (MSC) and increase the amount of CD11b+ CD11c+ dendritic cells in the spleen of mice immunized with vaccinia virus. Determination of viral DNA isolated from the ovaries of infected animals did not reveal differences in replication between rVACVs in this organ. Coexpression of Flt3L by replication-competent virus P13-FL-SigE7LAMP induced enhancement of the cellular immune response against HPV16 E7 and VACV E3 proteins as well as increased anti-tumor efficacy in both the protective and therapeutic immunization schemes. On the other hand, the short-time Flt3L coexpression by MVA-H5-FL-SigE7LAMP was not sufficient to enhance anti-tumor effect of immunization.
- MeSH
- analýza rozptylu MeSH
- antigen prezentující buňky imunologie MeSH
- CD8-pozitivní T-lymfocyty imunologie MeSH
- ELISA MeSH
- genetické vektory genetika imunologie MeSH
- lidé MeSH
- membránové proteiny biosyntéza genetika imunologie MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- nádory imunologie terapie MeSH
- protinádorové vakcíny genetika imunologie MeSH
- transfekce MeSH
- virus vakcinie genetika imunologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
Mosquitoes (Diptera: Culicidae) act as vectors of medical and veterinary importance, due to their ability to transmit many pathogens and parasites. Renewed interest has been recently devoted to the potential of sterile insect technique (SIT) for mosquito suppression. However, the success of the SIT is mostly dependent on the ability of sterile males to compete for mates with the wild ones in the field. Nevertheless, little is known on the sexual chemical ecology of mosquitoes, with special reference to the role of chemical signals in males. We reviewed the current knowledge on mosquito sexual chemical ecology and other key cues affecting courtship and mating behavior. The information available on the aggregation and sex pheromones in mosquito males is rather limited. To the best of our knowledge, the components of the aggregation pheromone stimulating swarming mechanisms have been fully characterized only for Aedes aegypti, while evidence for aggregation pheromones in other mosquito species remains elusive. Further research on this issue is needed, as well as to dissect the relative importance of visual (with special reference to swarming landmarks), vibrational, olfactory and tactile cues perceived during swarming and mate. On the other hand, more knowledge is available for cuticular hydrocarbons, which modulate mating behavior in several species of economic importance. These compounds, coupled with volatile aggregation components, have potential interest for the development of monitoring and trapping systems. In addition, the analyses of cuticular hydrocarbons are essential for discrimination between closely related mosquito species and/or populations.
- MeSH
- Aedes fyziologie MeSH
- biologická kontrola škůdců metody MeSH
- Culicidae fyziologie MeSH
- feromony fyziologie MeSH
- infertilita MeSH
- komáří přenašeči * MeSH
- moskyti - kontrola metody MeSH
- rozmnožování MeSH
- sexuální chování zvířat * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
