The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Maria Grazia Cusi - One of the best experts on this subject based on the ideXlab platform.
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Toscana Virus non structural protein nss acts as e3 ubiquitin ligase promoting rig i degradation
PLOS Pathogens, 2019Co-Authors: Gianni Gori Savellini, Gabriele Anichini, Claudia Gandolfo, Shibily Prathyumnan, Maria Grazia CusiAbstract:It is known that the non-structural protein (NSs) of Toscana Virus (TOSV), an emergent sandfly-borne Virus causing meningitis or more severe central nervous system injuries in humans, exerts its function triggering RIG-I for degradation in a proteasome-dependent manner, thus breaking off the IFN-β production. The non-structural protein of different members of Bunyavirales has recently appeared as a fundamental protagonist in immunity evasion through ubiquitination-mediated protein degradation targets. We showed that TOSV NSs has an E3 ubiquitin ligase activity, mapping at the carboxy-terminal domain and also involving the amino-terminal of the protein. Indeed, neither the amino- (NSsΔN) nor the carboxy- (NSsΔC) terminal-deleted mutants of TOSV NSs were able to cause ubiquitin-mediated proteasome degradation of RIG-I. Moreover, the addition of the C-terminus of TOSV NSs to the homologous protein of the Sandfly Fever Naples Virus, belonging to the same genus and unable to inhibit IFN-β activity, conferred new properties to this protein, favoring RIG-I ubiquitination and its degradation. NSs lost its antagonistic activity to IFN when one of the terminal residues was missing. Therefore, we showed that NSs could behave as an atypical RING between RING (RBR) E3 ubiquitin ligases. This is the first report which identified the E3 ubiquitin ligase activity in a viral protein among negative strand RNA Viruses.
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Toscana Virus nss protein inhibits the induction of type i interferon by interacting with rig i
Journal of Virology, 2013Co-Authors: Gianni Gorisavellini, Melissa Valentini, Maria Grazia CusiAbstract:Toscana Virus (TOSV) is a phleboVirus, of the Bunyaviridae family, that is responsible for central nervous system (CNS) injury in humans. Previous data have shown that the TOSV NSs protein is a gamma interferon (IFN-β) antagonist when transiently overexpressed in mammalian cells, inhibiting IRF-3 induction (G. Gori Savellini, F. Weber, C. Terrosi, M. Habjan, B. Martorelli, and M. G. Cusi, J. Gen. Virol. 92:71-79, 2011). In this study, we investigated whether an upstream sensor, which has a role in the signaling cascade leading to the production of type I IFN, was involved. We found a significant decrease in RIG-I protein levels in cells overexpressing TOSV NSs, suggesting that the nonstructural protein interacts with RIG-I and targets it for proteasomal degradation. In fact, the MG-132 proteasome inhibitor was able to restore IFN-β promoter activation in cells expressing NSs, demonstrating the existence of an evasion mechanism based on inhibition of the RIG-I sensor. Furthermore, a C-terminal truncated NSs protein (ΔNSs), although able to interact with RIG-I, did not affect the RIG-I-mediated IFN-β promoter activation, suggesting that the NSs domains responsible for RIG-I-mediated signaling and interaction with RIG-I are mapped on different regions. These results contribute to identify a novel mechanism for bunyaViruses by which TOSV NSs counteracts the early IFN response.
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immunoglobulin m seropositivity for Toscana Virus in a random population sample in sicily
International Journal of Infectious Diseases, 2012Co-Authors: Emanuele Amodio, Maria Grazia Cusi, Melissa Valentini, Rosalia Maria Valenti, Caterina Mammina, Gianni Gorisavellini, Francesco Vitale, Nino Romano, James J Goedert, Giuseppe CalamusaAbstract:Summary Objectives High Toscana Virus (TOSV) antibody seropositivity rates have been documented in the last decade, especially in the Mediterranean area. It is unclear if these rates are associated with a recent or past exposure to the Virus. This is of importance, as primary infection can cause neurologic complications, especially in adults. The aim of the present study was to assess the current active TOSV circulation in western Sicily. Methods A cross-sectional seroprevalence study was conducted on 271 individuals aged 4–92 years, sampled from the general population of a small city. Each participant completed a self-administered questionnaire and provided serum, which was analyzed for the presence of specific anti-TOSV IgM and IgG. Results Anti-TOSV IgM was detected in eight (3.0%) participants, of whom only three had anti-TOSV IgG. The prevalence of anti-TOSV IgM was highest in subjects aged 25–34 and 35–44 years (7.1% and 4.8%, respectively). All subjects positive for anti-TOSV IgM were resident in the suburban area. Conclusions The detection of IgM documented the circulation of TOSV, a PhleboVirus, in a random population sample of Sicilian adults. The highest risk of TOSV seroconversion in subjects living in the suburbs appears to suggest a high density of TOSV vectors in peri-urban areas.
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diagnostic tools for Toscana Virus infection
Expert Review of Anti-infective Therapy, 2011Co-Authors: Maria Grazia Cusi, Gianni Gori SavelliniAbstract:Toscana Virus (TOSV; PhleboVirus, Bunyaviridae) is an important etiological agent of acute meningitis and meningoencephalitis in Mediterranean countries. Laboratory diagnosis has been carried out in serological studies using ELISA, immunofluorescence and/or neutralization tests that are not influenced by the Virus viability; however, in the acute phase of the infection, nucleic acid amplification techniques are the methods of choice to diagnose viral meningitis from cerebrospinal fluid samples. Molecular methods are rapid and sensitive and, unlike traditional methods, such as Virus isolation by cell culture, they are not influenced by the viability of the Virus in the clinical specimen; however, the RNA integrity is crucial for the success of these methods. Real-time PCR is the most important molecular method used in laboratories worldwide, since it is less time-consuming and it reduces the risk of contamination. Therefore, a sensitive real-time PCR has been developed for diagnosis of suspected cases of TOSV infection either autochthonous and/or imported, since a new lineage of TOSV, divergent from the Italian prototype, has recently been reported in Spain.
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Toscana Virus induces interferon although its nss protein reveals antagonistic activity
Journal of General Virology, 2011Co-Authors: Gianni Gori Savellini, Friedemann Weber, Chiara Terrosi, Matthias Habjan, Barbara Martorelli, Maria Grazia CusiAbstract:Toscana Virus (TOSV) is a phlebotomus-transmitted Virus that belongs to the family Bunyaviridae and causes widespread infections in humans; about 30 % of these cases result in aseptic meninigitis. In the present study, it was shown that TOSV is an inducer of beta interferon (IFN-β), although its non-structural protein (NSs) could inhibit the induction of IFN-β if expressed in a heterologous context. A recombinant Rift Valley fever Virus expressing the TOSV NSs could suppress IFN-β expression in infected cells. Moreover, in cells expressing NSs protein from a cDNA plasmid, IFN-β transcripts were not inducible by poly(I : C). Unlike other members of the family Bunyaviridae, TOSV appears to express an NSs protein that is a weak antagonist of IFN induction. Characterization of the interaction of TOSV with the IFN system will help our understanding of Virus–host cell interactions and may explain why the pathogenesis of this disease is mostly mild in humans.
Rémi N. Charrel - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a trio Toscana Virus real time rt pcr assay targeting three genomic regions within nucleoprotein gene
Pathogenetics, 2021Co-Authors: Laurence Thirion, Xavier De Lamballerie, Mercedes Perezruiz, Sara Sanbonmatsugamez, Alessandra Falchi, Laura Pezzi, Irene Pedrosacorral, Rémi N. CharrelAbstract:Toscana Virus (TOSV) can cause central nervous system infections in both residents of and travelers to Mediterranean countries. Data mining identified three real-time RT-qPCR assays for detecting TOSV RNA targeting non-overlapping regions in the nucleoprotein gene. Here, they were combined to create a multi-region assay named Trio TOSV RT-qPCR consisting of six primers and three probes. In this study, (i) we evaluated in silico the three RT-qPCR assays available in the literature for TOSV detection, (ii) we combined the three systems to create the Trio TOSV RT-qPCR, (iii) we assessed the specificity and sensitivity of the three monoplex assays versus the Trio TOSV RT-qPCR assay, and (iv) we compared the performance of the Trio TOSV RT-qPCR assay with one of the reference monoplex assays on clinical samples. In conclusion, the Trio TOSV RT-qPCR assay performs equally or better than the three monoplex assays; therefore, it provides a robust assay that can be used for both research and diagnostic purposes.
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an update on Toscana Virus distribution genetics medical and diagnostic aspects
Clinical Microbiology and Infection, 2020Co-Authors: Nazli Ayhan, Rémi N. CharrelAbstract:Abstract Background Toscana Virus is an arboVirus transmitted by sand flies within the Mediterranean area where it can cause febrile illness and neuroinvasive infections during the seasonal circulation period of the vector. Although it is an important cause of meningitis and encephalitis, it remains a neglected Virus with limited published data, as demonstrated by Objective The last review article on Toscana Virus was published in 2012. The aim was to compile peer-reviewed articles to provide an updated review highlighting recent findings to complement previous review articles. Sources PubMed database was searched using the ‘Toscana Virus' keyword from 2010 to present. A total of 152 articles were retrieved and identified studies were assessed for novel information on Virus genetics, and geographic and medical aspects compared with existing knowledge reported in previous review articles. Content Studies addressing medical, veterinary and entomological aspects have provided evidence that Toscana Virus is present in North Africa, in the Balkan Peninsula, and in most of the Mediterranean islands. Besides the two previously recognized genetic lineages, a novel evolutionary lineage has been identified in the Balkan Peninsula. Co-circulation of two genetic lineages has been demonstrated in France, in Turkey and in Croatia. In addition to meningitis and meningo-encephalitis, which have been reported for 40 years, various neuroinvasive forms have been recently reported such as Guillain–Barre syndrome, hydrocephalus, myositis, fasciitis, polymyeloradiculopathy, deafness and facial paralysis. Implication Because it is endemic in countries bordering the Mediterranean, physicians should include Toscana Virus in the differential diagnosis of patients presenting with febrile illness and/or neurological manifestations.
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complete coding sequences of six Toscana Virus strains isolated from human patients in france
Genome Announcements, 2016Co-Authors: Amal Baklouti, Xavier De Lamballerie, Bruno Coutard, Nicolas Papageorgiou, Geraldine Piorkowski, Isabelle Leparcgoffart, Rémi N. CharrelAbstract:ABSTRACT Toscana Virus (TOSV) is an arthropod-borne phleboVirus belonging to the Sandfly fever Naples Virus species (genus PhleboVirus, family Bunyaviridae). Here, we report the complete coding sequences of six TOSV strains isolated from human patients having acquired the infection in southeastern France during a 12-year period.
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complete coding sequences of three Toscana Virus strains isolated from sandflies in france
Genome Announcements, 2016Co-Authors: Amal Baklouti, Xavier De Lamballerie, Bruno Coutard, Nicolas Papageorgiou, Isabelle Leparc Goffard, Geraldine Piorkowski, Rémi N. CharrelAbstract:ABSTRACT Toscana Virus (TOSV) is an arthropod-borne Virus belonging to the sandfly fever Naples Virus species within the genus PhleboVirus. We report here the complete coding sequences of three TOSV strains belonging to lineage B and isolated from sandflies trapped in the Southeast of France between 2009 and 2013.
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Seroprevalence of Toscana Virus in dogs from Corsica, France
Parasites and Vectors, 2016Co-Authors: Mustapha Dahmani, Sulaf Alwassouf, Sébastien Grech-angelini, Jeanlou Marie, Rémi N. CharrelAbstract:BACKGROUND: Toscana Virus (TOSV) is an arboVirus belonging to the Bunyaviridae, a family of negative-stranded, enveloped RNA Viruses. The Virus can be transmitted to humans through the bite of an infected female sand fly of the genus Phlebotomus. Infections are usually asymptomatic but the Virus is known to cause aseptic meningitis and/or meningo-encephalitis in the Mediterranean countries. Dogs are good sentinels for detection of viral circulation and are more easily accessible than wild animals.\n\nFINDINGS: In 2013 and 2014, we collected sera from 231 adult dogs living in 26 counties in two departments in Corsica, a French island in the Mediterranean. The Virus microneutralization-based seroprevalence assay revealed a seropositivity of 3.9 % dogs on the eastern coast of Corsica.\n\nCONCLUSIONS: Our study confirms the circulation of TOSV in Corsica. Accordingly, in geographical areas where dogs possess TOSV neutralizing antibodies, direct and indirect TOSV diagnosis should be implemented in patients presenting with febrile illnesses and central nervous system infections such as meningitis and encephalitis.
Maria Grazia Ciufolini - One of the best experts on this subject based on the ideXlab platform.
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Bovine Lactoferrin Inhibits Toscana Virus Infection by Binding to Heparan Sulphate
MDPI AG, 2015Co-Authors: Agostina Pietrantoni, Maria Grazia Ciufolini, Claudia Fortuna, Maria Elena Remoli, Fabiana SupertiAbstract:Toscana Virus is an emerging sandfly-borne bunyaVirus in Mediterranean Europe responsible for neurological diseases in humans. It accounts for about 80% of paediatric meningitis cases during the summer. Despite the important impact of Toscana Virus infection-associated disease on human health, currently approved vaccines or effective antiviral treatments are not available. In this research, we have analyzed the effect of bovine lactoferrin, a bi-globular iron-binding glycoprotein with potent antimicrobial and immunomodulatory activities, on Toscana Virus infection in vitro. Our results showed that lactoferrin was capable of inhibiting Toscana Virus replication in a dose-dependent manner. Results obtained when lactoferrin was added to the cells during different phases of viral infection showed that lactoferrin was able to prevent viral replication when added during the viral adsorption step or during the entire cycle of Virus infection, demonstrating that its action takes place in an early phase of viral infection. In particular, our results demonstrated that the anti-Toscana Virus action of lactoferrin took place on Virus attachment to the cell membrane, mainly through a competition for common glycosaminoglycan receptors. These findings provide further insights on the antiviral activity of bovine lactoferrin
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serological evidence of Toscana Virus infection in portuguese patients
Epidemiology and Infection, 2012Co-Authors: Fatima Amaro, Maria Grazia Ciufolini, Antonella Marchi, T Luz, P Parreira, Maria Joao AlvesAbstract:Toscana Virus (TOSV) is an emerging PhleboVirus of growing interest as a human pathogen in the Mediterranean Basin. In Portugal, however, little is known about the prevalence of TOSV infection. The aim of this work was to perform a seroprevalence study in patients with requests for laboratory diagnosis of vector-borne Viruses. A total of 538 patients with and without neurological signs from 2004 to 2008 were studied by in-house indirect immunofluorescence assay and commercial enzyme-linked immunosorbent assays. A prevalence of 4.2% for IgG antibodies was found in the group of patients with neurological signs. Five (3%) of these had recent infections. In the group with no neurological signs, the IgG prevalence was 1.3%. Two samples, belonging to two patients, were also confirmed with plaque reduction neutralization tests with the TOSV ISS. Phl.3 Italian strain. This work showed that TOSV is present and causing disease from north to south in Portugal. The probable circulation of different phleboVirus serotypes in Portugal emphasizes the need for further studies.
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Toscana Virus in the portuguese population serosurvey and clinical cases
Acta Médica Portuguesa, 2011Co-Authors: Fatima Amaro, Maria Grazia Ciufolini, Antonella Marchi, T Luz, P Parreira, Nuno Janeiro, Alexandra Zagalo, Paula Proenca, Maria Isabel Ramos, Maria Joao AlvesAbstract:Toscana Virus (PhleboVirus genus, Bunyaviridae family) is a neurotropic Virus which circulates in the Mediterranean Basin. Although Portugal has been the second country where its presence was reported, the existence of this Virus in our country has been referred only sporadically, and there is a lack of knowledge regarding the prevalence of antibodies in the population. Thus, the objective of this study was to analyse the prevalence of antibodies anti-Toscana Virus in the human population in our country. Sero-epidemiological investigations were performed with indirect immunofluorescence assay (IFA) and enzyme linked immunosorbent assay (ELISA) tests. The study population consisted of a control population (blood donors, n=150), a population considered at risk (n=236) and a population of individuals with symptoms and laboratory diagnostic request for vector-borne Viruses. The latter population was divided into two groups: those individuals with neurological symptoms (n=165) and those without neurological symptoms (n=373). We tested sera from a total of 924 individuals. The seroprevalence of IgG antibodies in the control population was 2%. In the population considered at risk, the prevalence was 3.4%. In the population with central nervous system disease, we detected a seroprevalence of 4.2%. For the same type of antibodies and in subjects without central nervous system disease, the prevalence was 1.3%. Five cases of recent infection (3%) were detected in the population with neurological signs. Those infections have been acquired in the districts of Faro, Coimbra, Aveiro and Lisbon. The associated clinical diagnoses were meningitis, meningoencephalitis and rash. The observed seroprevalences were, in general, lower than reported in other endemic countries. Only 5 of the 29 sera which gave positive results by IFA and ELISA were confirmed by plaque reduction neutralization tests with the Italian strain ISS.Phl.3. This can indicate the presence of more than one Toscana Virus serotype circulating in Portugal and emphasizes the need for more research about this etiological agent in our country.
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occupational risk associated with Toscana Virus infection in tuscany italy
Occupational Medicine, 2008Co-Authors: Maria Concetta Dovidio, Maria Grazia Ciufolini, Cristiano Fiorentini, Giulietta Venturi, Giulia Barbati, Simona Di Renzi, N Vonesch, P TomaoAbstract:Background Sandfly fever Virus serotype Toscana is endemic in Mediterranean countries and is a widespread public health problem as it may be associated with acute neurological diseases such as aseptic meningitis. Aim To assess whether Toscana Virus infection is associated with occupational exposure. Methods During the summer of 2001, a total of 678 blood samples were taken from healthy subjects residing in Tuscany (349 agricultural and forestry workers and 329 control subjects living in the same areas). Information on age, type of job and lifestyle was collected in a questionnaire, and sera were analysed using enzyme-linked immunosorbent assay for Toscana Virus-specific antibodies. Results Seropositivity to antibodies to Toscana Virus was 30% in the control group and 23% in the agricultural and forestry workers (P < 0.05). Questionnaire responses suggested that, although the agricultural and forestry workers had a potentially greater continuous exposure to sandfly fever Virus (outdoor activities, rural residence and at-risk lifestyle), these risk factors did not add significant information about greater susceptibility to disease. Conclusion Our findings indicate a need for better understanding of the best preventive measures to avoid the risk related to sandfly bites, especially for people who live or work in areas at risk.
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detection of Toscana Virus central nervous system infections in sardinia island italy
Journal of Clinical Virology, 2007Co-Authors: Giulietta Venturi, Cristiano Fiorentini, G Madeddu, Giovanni Rezza, Massimo Ciccozzi, Maria Laura Pettinato, Marco Cilliano, Maria Stella Anna Mura, Maria Grazia CiufoliniAbstract:Toscana Virus (TOSV) (genus PhleboVirus, family Bunyaviridae) was isolated in 1971 from the sandfly Phlebotomus perniciosus in central Italy (Verani et al., 1982). We have investigated the role of TOSV in cases of CNS disease occurring during the summer in the island of Sardinia, Italy. Moreover, a sequence analysis has been performed to assess the circulating TOSV genotype. However, because of the small number of sequenced viral strains, we cannot rule out the cocirculation in the island of different genotypes.
Xavier De Lamballerie - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a trio Toscana Virus real time rt pcr assay targeting three genomic regions within nucleoprotein gene
Pathogenetics, 2021Co-Authors: Laurence Thirion, Xavier De Lamballerie, Mercedes Perezruiz, Sara Sanbonmatsugamez, Alessandra Falchi, Laura Pezzi, Irene Pedrosacorral, Rémi N. CharrelAbstract:Toscana Virus (TOSV) can cause central nervous system infections in both residents of and travelers to Mediterranean countries. Data mining identified three real-time RT-qPCR assays for detecting TOSV RNA targeting non-overlapping regions in the nucleoprotein gene. Here, they were combined to create a multi-region assay named Trio TOSV RT-qPCR consisting of six primers and three probes. In this study, (i) we evaluated in silico the three RT-qPCR assays available in the literature for TOSV detection, (ii) we combined the three systems to create the Trio TOSV RT-qPCR, (iii) we assessed the specificity and sensitivity of the three monoplex assays versus the Trio TOSV RT-qPCR assay, and (iv) we compared the performance of the Trio TOSV RT-qPCR assay with one of the reference monoplex assays on clinical samples. In conclusion, the Trio TOSV RT-qPCR assay performs equally or better than the three monoplex assays; therefore, it provides a robust assay that can be used for both research and diagnostic purposes.
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Circulation of Toscana Virus in a Sample Population of Corsica, France
Viruses, 2019Co-Authors: Shirley Masse, Xavier De Lamballerie, Remi Charrel, Nazli Ayhan, Lisandru Capai, Frédéric Bosseur, Alessandra FalchiAbstract:Sandfly-borne phleboViruses pathogenic to humans, such as Toscana Virus (TOSV) and Sandfly Fever Sicilian Virus (SFSV), are endemic in the Mediterranean region. In France, several autochthonous cases of TOSV infection have been described, causing either meningitis or encephalitis. The aim of the present study was to investigate the seroprevalence of TOSV and SFSV antibodies in a healthy population from Corsica. In this cross-sectional study, participants were enrolled (i) from a medical staff at the University of Corsica and (ii) from general practitioners of the Corsican Sentinelles Network. The seroprevalence study was based on a Virus microneutralization assay. A total of 240 sera were tested. Altogether, 54 sera (22.5%) were confirmed positive for TOSV antibodies, whereas none were positive for SFSV (0/240). The residential district of participants was significantly associated with TOSV seropositivity (p value = 0.005). The rate of the seropositivity against TOSV in our study suggests that the Corsican population is well exposed to the TOSV. These results encourage the implementation of a systematic surveillance system including entomological, microbiological, and medical aspects for the collection of better information on the diseases that are associated with phleboViruses in Corsica and beyond in the regions where these Viruses are present.
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complete coding sequences of six Toscana Virus strains isolated from human patients in france
Genome Announcements, 2016Co-Authors: Amal Baklouti, Xavier De Lamballerie, Bruno Coutard, Nicolas Papageorgiou, Geraldine Piorkowski, Isabelle Leparcgoffart, Rémi N. CharrelAbstract:ABSTRACT Toscana Virus (TOSV) is an arthropod-borne phleboVirus belonging to the Sandfly fever Naples Virus species (genus PhleboVirus, family Bunyaviridae). Here, we report the complete coding sequences of six TOSV strains isolated from human patients having acquired the infection in southeastern France during a 12-year period.
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complete coding sequences of three Toscana Virus strains isolated from sandflies in france
Genome Announcements, 2016Co-Authors: Amal Baklouti, Xavier De Lamballerie, Bruno Coutard, Nicolas Papageorgiou, Isabelle Leparc Goffard, Geraldine Piorkowski, Rémi N. CharrelAbstract:ABSTRACT Toscana Virus (TOSV) is an arthropod-borne Virus belonging to the sandfly fever Naples Virus species within the genus PhleboVirus. We report here the complete coding sequences of three TOSV strains belonging to lineage B and isolated from sandflies trapped in the Southeast of France between 2009 and 2013.
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Virus isolation genetic characterization and seroprevalence of Toscana Virus in algeria
Clinical Microbiology and Infection, 2015Co-Authors: Cigdem Alkan, Sulaf Alwassouf, Arezki Izri, Xavier De Lamballerie, Amal Baklouti, Geraldine Piorkowski, A B Allalikhlef, Rémi N. CharrelAbstract:Toscana Virus (TOSV; Bunyaviridae, PhleboVirus) is transmitted by sandflies of the genus Phlebotomus in the Mediterranean area. One strain of TOSV was isolated from a total of almost 23 000 sandflies collected in Kabylia, Algeria. The complete genome was sequenced, and phylogenetic studies indicated that it was most closely related with TOSV strain from Tunisia within lineage A, which also includes Italian, French and Turkish strains. A seroprevalence study performed on 370 sera collected from people living in the same area showed that almost 50% possessed neutralizing antibodies against TOSV, a rate much higher than that observed in Southern Europe. Sandfly species distribution in the study area suggests that the vector of TOSV in this region belongs to the subgenus Larroussius. These data support the rapid implementation of the diagnosis of TOSV in clinical microbiology laboratories to estimate the burden in patients presenting with neuroinvasive infections and febrile illness.
Marcello Valassina - One of the best experts on this subject based on the ideXlab platform.
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nucleotide variability of Toscana Virus m segment in strains isolated from clinical cases
Virus Research, 2008Co-Authors: Melissa Valentini, Marcello Valassina, Gianni Gori Savellini, Maria Grazia CusiAbstract:Abstract Toscana Virus (TOSV), a member of the Bunyaviridae family, is an important etiologic agent of neurologic infection transmissible to humans by bites of the Phlebotomus spp. In consideration of the variations in the antigenic properties of BunyaViruses and their potential genetic variability, we analysed a large region (2500 nt) of the Toscana Virus M segment coding for the non-structural protein (NSm) and the GN and GC glycoproteins in several strains isolated from patients with meningitis from 1998 to 2004 in the region of Tuscany in Italy. The sequences were compared with the reference strain of Toscana Virus isolated from phlebotomus (ISS Phl. 3) and revealed some changes in amino acids, particularly in the GC protein, that are probably involved in recognition and binding to the cell receptor. The analyses were aimed at identifying the amino acid changes commonly to all of the clinical isolates potentially related to TOSV virulence.
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development of a mouse model for the study of Toscana Virus pathogenesis
Virology, 2005Co-Authors: Maria Grazia Cusi, Marcello Valassina, Melissa Valentini, Gianni Gori Savellini, Chiara Terrosi, Giuseppa Di Genova, Sabrina Bartolommei, Clelia MiraccoAbstract:Toscana Virus (TOSV) has recently been recognized as an emerging Virus transmitted by phlebotomus vectors, responsible for acute neurological diseases in Mediterranean countries. In our study, we demonstrated that adult Balb/c mice were susceptible to TOSV when infected intracerebrally (ic.) or subcutaneously (sc.) with a neuroadapted strain of the Virus. We have shown that by performing serial passages of a wild type human isolate of TOSV in mouse brains, selection occurs for a highly virulent variant which replicates efficiently in the central nervous system (CNS) of ic.-injected mice, causing acute encephalitis and death. Immunohistochemical analysis and TUNEL assay of post-mortem organs showed that TOSV replication was highly restricted to neurons in which it induced apoptotic death; however, Virus antigen-positivity was also observed in the spleen and lymph nodes. In sc.-injected mice, Virus was detectable in the spleen and lymph nodes, whereas only few meningeal cells and neurons were affected, allowing for the mouse survival the infection. The presence of TOSV in spleen and lymph node cells in both sc.- and ic.-treated mice suggests their possible involvement in the diffusion of the infection. This animal model may be helpful for the development of prophylactic measures against TOSV infections.
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A Mediterranean arboVirus: The Toscana Virus
Journal of NeuroVirology, 2003Co-Authors: Marcello Valassina, Maria Grazia Cusi, Pier Egisto ValensinAbstract:Toscana Virus (Bunyaviridae family, PhleboVirus genus) is a sandfly fever Virus responsible for human neurological infections. Sandfly Viruses are transmitted by insect vectors (Phlebotomus species) and the infection is present in climatic areas that allow the life cycle of the vector. The arthropode-borne Toscana Virus is the etiologic agent of meningitis, meningoencephalitis, and encephalitis. The frequency of this neuropathic infection increases in the summer months, peaking in August in the endemic Mediterranean areas (Italy, Portugal, Spain, and Cyprus). Infection diagnosis is carried out by molecular assays and immunoenzymatic tests, which are rapid and sensitive. Recent studies have investigated the antigenic properties of the viral proteins (nucleoprotein N and surface glycoproteins G1 and G2), to better understand their immunogentic role.
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serological survey of Toscana Virus infections in a high risk population in italy
Clinical and Vaccine Immunology, 2003Co-Authors: Marcello Valassina, Pier Egisto Valensin, Melissa Valentini, A Pugliese, Maria Grazia CusiAbstract:Toscana Virus is the most important agent responsible for meningitis in central Italy. We report a serosurveillance study, using an immunoenzymatic assay, of 360 serum samples harvested from a high-risk population occupationally exposed to Toscana Virus in two regions of Italy, Tuscany and Piedmont. The results indicates a seroprevalence of Toscana Virus of 77.2% in the forestry workers, particularly in the Tuscany region. This fact is strictly correlated with the ecological niches specific for the survival of Toscana Virus arthropod vector.
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fast duplex one step rt pcr for rapid differential diagnosis of entero or Toscana Virus meningitis
Diagnostic Microbiology and Infectious Disease, 2002Co-Authors: Marcello Valassina, Pier Egisto Valensin, Melissa Valentini, Maria Grazia CusiAbstract:Acute meningitis is the most common neurologic disease that involves the central nervous system. The spectrum of infectious agents that cause neurologic infection is remarkably broad and numerous Viruses are the most frequent cause of the aseptic meningitis syndrome. We applied a multiplex one-step method for the rapid detection of the genomic RNA of different neurotropic Viruses: particles in the genus EnteroVirus and Toscana Virus, which are the most representative aetiologic agents in our country during the spring-summer period. We have evaluated the sensitivity and the specificity of the multiplex one-step test on positive controls and on RNA extracted from clinical samples harvested from 475 patients with meningitis hospitalized during the 1996-2001 period. The multiplex one-step RT-nPCR protocol allows for the detection of enteroVirus and Toscana Virus RNA in a single sample, by using, at the same time, a very small clinical sample volume. In our study we were able to diagnose 192 cases of meningitis by Toscana Virus and 31 cases by enteroViruses out of 475 cases of meningitis utilizing the described one-step multiplex method.
