Severe encephalitis caused by Toscana virus, Greece

Emergence of Toscana Virus, Romania, 2017-2018

We describe a series of severe neuroinvasive infections caused by Toscana virus, identified by real-time reverse transcription PCR testing, in 8 hospitalized patients in Bucharest, Romania, during the summer seasons of 2017 and 2018. Of 8 patients, 5 died. Sequencing showed that the circulating virus belonged to lineage A.

Evaluation of a Trio Toscana Virus Real-Time RT-PCR Assay Targeting Three Genomic Regions within Nucleoprotein Gene

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.

Clinical, Virological, and Immunological Findings in Patients with Toscana Neuroinvasive Disease in Croatia: Report of Three Cases

Toscana virus (TOSV) is an arthropod-borne virus, transmitted to humans by phlebotomine sandflies. Although the majority of infections are asymptomatic, neuroinvasive disease may occur. We report three cases of neuroinvasive TOSV infection detected in Croatia. Two patients aged 21 and 54 years presented with meningitis, while a 22-year old patient presented with meningoencephalitis and right-sided brachial plexitis. Cerebrospinal fluid (CSF), serum, and urine samples were collected and tested for neuroinvasive arboviruses: tick-borne encephalitis, West Nile, Usutu, TOSV, Tahyna, and Bhanja virus. In addition, CSF and serum samples were tested for the anti-viral cytokine response. High titers of TOSV IgM (1000–3200) and IgG (3200−10,000) antibodies in serum samples confirmed TOSV infection. Antibodies to other phleboviruses (sandfly fever Sicilian/Naples/Cyprus virus) were negative. CSF samples showed high concentrations of interleukin 6 (IL-6; range 162.32−2683.90 pg/mL), interferon gamma (IFN-γ; range 110.12−1568.07 pg/mL), and IL-10 (range 28.08−858.91 pg/mL), while significantly lower cytokine production was observed in serum. Two patients recovered fully. The patient with a brachial plexitis improved significantly at discharge. The presented cases highlight the need of increasing awareness of a TOSV as a possible cause of aseptic meningitis/meningoencephalitis during summer months. Association of TOSV and brachial plexitis with long-term sequelae detected in one patient indicates the possibility of more severe disease, even in young patients.

Development of a Reverse Genetics System for Toscana Virus (Lineage A)

Toscana virus (TOSV) is a Phlebovirus in the Phenuiviridae family, order Bunyavirales, found in the countries surrounding the Mediterranean. TOSV is an important cause of seasonal acute meningitis and encephalitis within its range. Here, we determined the full sequence of the TOSV strain 1500590, a lineage A virus obtained from an infected patient (Marseille, 2007) and used this in combination with other sequence information to construct functional cDNA plasmids encoding the viral L, M, and S antigenomic sequences under the control of the T7 RNA promoter to recover recombinant viruses. Importantly, resequencing identified two single nucleotide changes to a TOSV reference genome, which, when corrected, restored functionality to the polymerase L and made it possible to recover infectious recombinant TOSV (rTOSV) from cDNA, as well as establish a minigenome system. Using reverse genetics, we produced an NSs-deletant rTOSV and also obtained viruses expressing reporter genes instead of NSs. The availability of such a system assists investigating questions that require genetic manipulation of the viral genome, such as investigations into replication and tropism, and beyond these fundamental aspects, also the development of novel vaccine design strategies.

An update on Toscana virus distribution, genetics, medical and diagnostic aspects

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 <250 peer-reviewed articles since the 1970s.

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-Barré 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.

Emerging arboviruses of medical importance in the Mediterranean region

The epidemiology of viral infections transmitted by arthropods is changing due to a variety of parameters related to the virus, the host and the environment. The Mediterranean region is highly affected by changes in the intensity and extension of global-scale climate patterns, and, due to its location, it provides a vulnerable environment for emergence of arboviral diseases. The main arboviruses that pose currently a public health threat in the Mediterranean region are West Nile virus and Crimean-Congo hemorrhagic fever virus and, in less extend, tick-borne encephalitis virus. Usutu virus that affects mainly birds, can infect also humans, while Dengue and Chikungunya viruses showed that they are capable to cause sporadic autochthonous cases, and even outbreaks in the Mediterranean region. Sandly-transmitted viruses continue to have a public health impact, and novel ones have been identified. The presence of competent vectors (mainly mosquitoes), combined by arbovirus introduction through viremic travelers returning from endemic regions, prompt for increased surveillance to mitigate the risk for local transmission. In order to tackle efficiently and effectively the emerging arboviral diseases, an integrated "One Health initiative" is required to be maintained, involving public health, animal health and environmental authorities. Awareness of medical and veterinary staff and laboratory capacity are crucial for the early detection of pathogens, while reporting the unusual and enhance surveillance are important.

Diagnostic tools to tackle infectious causes of encephalitis and meningoencephalitis in immunocompetent adults in Europe

BACKGROUND

Encephalitis and meningoencephalitis imply inflammation of the brain parenchyma, and comprise many diagnostic entities, such as various infections and causes of dysimmunity. The cause remains unknown in around 50% of cases.

OBJECTIVES

To summarize the main infectious causes of encephalitis and meningoencephalitis acquired in Europe, and the diagnostic means to identify them.

SOURCES

PubMed, ECDC and WHO websites, personal experience.

CONTENT

The principal infectious causes of encephalitis and meningoencephalitis acquired in Europe in adults are discussed in this review, with special emphasis on the microbiological and imaging diagnostic approaches. The role of electroencephalography in diagnosing encephalitis is also mentioned. Among infections, viruses are more frequent than other pathogen types, and their epidemiology varies according to geographic area. A few bacteria, such as Listeria monocytogenes and Mycobacterium tuberculosis, are also to be considered. In contrast, parasites and fungi are rare encephalitis causes in Europe.

IMPLICATIONS

Identifying the causative pathogen of infectious encephalitis and meningoencephalitis is complex because of the variety of pathogens, the epidemiology of which is determined by geography and environmental factors. Furthermore, despite extensive microbiological testing, many cases of encephalitis remain of unknown origin. Brain magnetic resonance imaging and electroencephalography are useful complementary diagnostic tools, and newer unbiased sequencing technologies might help to fill in the diagnostic gap.

Neglected vector-borne bacterial diseases and arboviruses in the Mediterranean area

Arthropod vectors can transmit pathogenic microorganisms from one vertebrate to another during their blood meal. Although some vector-borne diseases have been eradicated in the Mediterranean area, such as malaria and dengue, recent endemic microorganisms (Toscana virus, Rickettsia spp.) remain neglected even though they cause many more cases. New diagnostic tools and innovative tools for the identification and characterization of vector species and microorganisms have been developed at IHU Méditerranée Infection, either internally or through collaborative and integrated projects. We have detected Rickettsia slovaca as a human pathogen and have described the disease; we have shown that Rickettsia felis can be transmitted by Anopheles mosquitoes; we have emphasized the increasing importance of bedbug (Cimex lectularius) as a potential vector of Bartonella quintana; and we have described the Toscana virus, a major agent of meningitis and meningoencephalitis which was disseminated in North Africa and Central and Eastern Europe, where it frequently cocirculates with a large number of newly described phleboviruses transmitted by sand flies.

High Rates of Neutralizing Antibodies to Toscana and Sandfly Fever Sicilian Viruses in Livestock, Kosovo

Toscana and sandfly fever Sicilian viruses (TOSV and SFSV, respectively), both transmitted by sand flies, are prominent human pathogens in the Old World. Of 1,086 serum samples collected from cattle and sheep during 2013 in various regions of Kosovo (Balkan Peninsula), 4.7% and 53.4% had neutralizing antibodies against TOSV and SFSV, respectively.

Acute viral infections of the central nervous system, 2014-2016, Greece

In order to investigate the viral etiology of acute infections of central nervous system (CNS), multiplex and single PCRs combined with serology for arboviruses were applied on samples from 132 hospitalized patients in Greece during May 2014-December 2016. A viral pathogen was detected in 52 of 132 (39.4%) cases with acute CNS infection. Enteroviruses predominated (15/52, 28.8%), followed by West Nile virus (9/52, 17.3%). Phleboviruses, varicella-zoster virus, and Epstein-Barr virus accounted for 15.4%, 13.5%, and 11.5% of the cases, respectively. The study gives an insight into the etiology of viral CNS infections in a Mediterranean country, where arboviruses should be included in the differential diagnosis of acute CNS infections.

Phlebotomine sand fly-borne pathogens in the Mediterranean Basin: Human leishmaniasis and phlebovirus infections

Pathogens transmitted to humans by phlebotomine sand flies are neglected, as they cause infectious diseases that are not on the priority list of national and international public health systems. However, the infections caused by protozoa of the Leishmania genus and viruses belonging to the Phlebovirus genus (family Phenuiviridae)—the most significant group of viruses transmitted by sand flies—have a relevant role for human pathology. These infections are emerging in the Mediterranean region and will likely spread in forthcoming decades, posing a complex threat to human health. Four species and 2 hybrid strains of Leishmania are pathogenic for humans in the Mediterranean Basin, with an estimated annual incidence of 239,500–393,600 cases of cutaneous leishmaniasis and 1,200–2,000 cases of visceral leishmaniasis. Among the phleboviruses, Toscana virus can cause neuroinvasive infections, while other phleboviruses are responsible for a typical “3-day fever”; the actual incidence of Phlebovirus infections in the Mediterranean area is unknown, although at least 250 million people are exposed. Here, we reviewed the current literature on epidemiology of sand fly–borne infections in the Mediterranean Basin, with a focus on humans. Our analysis indicates the need for increased public health activities directed to determine the disease burden of these infections as well as to improve their surveillance. Among the emerging challenges concerning sand fly–borne pathogens, the relationships between sand fly–borne protozoa and viruses should be considered in future studies, including epidemiological links between Leishmania and phleboviruses as well as the conditional capacity for these pathogens to be involved in interactions that may evolve towards increased virulence.

Practical Guidelines for Studies on Sandfly-Borne Phleboviruses: Part I: Important Points to Consider Ante Field Work

The purpose of this review is to provide practical information to help researchers intending to perform "from field to laboratory" studies on phleboviruses transmitted by sandflies. This guideline addresses the different steps to be considered starting from the field collection of sandflies to the laboratory techniques aiming at the detection, isolation, and characterization of sandfly-borne phleboviruses. In this guideline article, we address the impact of various types of data for an optimal organization of the field work intending to collect wildlife sandflies for subsequent virology studies. Analysis of different data sets should result in the geographic positioning of the trapping stations. The overall planning, the equipment and tools needed, the manpower to be deployed, and the logistics to be anticipated and set up should be organized according to the objectives of the field study for optimal efficiency.

Preparing clinicians for (re-)emerging arbovirus infectious diseases in Europe

BACKGROUND

Arthropod-borne virus (Arbovirus) infections are considered an emerging threat for Europe, with an increase in cases in recent decades. The increase in global travel and trade has contributed to the introduction of vectors and viruses into new geographical areas. Tropical arboviruses such as dengue and chikungunya have re-emerged causing local, sporadic outbreaks ignited by travel-imported cases. The recent Zika virus outbreak in the Americas highlighted a need to strengthen preparedness for (re-)emerging arbovirus infections globally.

AIMS

To strengthen preparedness for the early identification of (re-)emerging arbovirus outbreaks in Europe and highlight areas for research.

SOURCES

An evidence review of published and grey literature together with consultations with European arbovirus experts.

CONTENT

This paper presents an overview of endemic and travel-imported arboviruses of clinical significance in Europe. The overview includes syndromic presentation, risk factors for infection and risk of transmission as well as an update on treatments and vaccinations and surveillance notifications and reporting. The paper also presents predictive modelled risks of further geographical expansion of vectors and viruses.

IMPLICATIONS

There are a range of arboviruses of clinical significance to Europe. There has been an increase in notifications of endemic and travel-imported arbovirus cases in recent years and an increased geographical range of vectors and viruses. The heterogeneity in surveillance reporting indicates a risk for the early identification of (re-)emerging outbreaks. The data presented show a need to strengthen preparedness for (re-)emerging arbovirus infections and a need for research into neglected arboviruses, risks of non-vector transmission and effective therapeutics and vaccinations.

Emerging arboviral human diseases in Southern Europe

Southern Europe is characterized by unique landscape and climate which attract tourists, but also arthropod vectors, some of them carrying pathogens. Among several arboviral diseases that emerged in the region during the last decade, West Nile fever accounted for high number of human cases and fatalities, while Crimean-Congo hemorrhagic fever expanded its geographic distribution, and is considered as a real threat for Europe. Viruses evolve rapidly and acquire mutations making themselves stronger and naive populations more vulnerable. In an effort to tackle efficiently the emerging arboviral diseases, preparedness and strategic surveillance are needed for the early detection of the pathogen and containment and mitigation of probable outbreaks. In this review, the main human arboviral diseases that emerged in Southern Europe are described.

Seroprevalence of Sandfly-Borne Phleboviruses Belonging to Three Serocomplexes (Sandfly fever Naples, Sandfly fever Sicilian and Salehabad) in Dogs from Greece and Cyprus Using Neutralization Test

Phleboviruses transmitted by sandflies are endemic in the Mediterranean area. The last decade has witnessed the description of an accumulating number of novel viruses. Although, the risk of exposure of vertebrates is globally assessed, detailed geographic knowledge is poor even in Greece and Cyprus where sandfly fever has been recognized for a long time and repeatedly. A total of 1,250 dogs from mainland Greece and Greek archipelago on one hand and 422 dogs from Cyprus on the other hand have been sampled and tested for neutralising antibodies against Toscana virus (TOSV), Sandfly fever Sicilian virus (SFSV), Arbia virus, and Adana virus i.e. four viruses belonging to the 3 sandfly-borne serocomplexes known to circulate actively in the Mediterranean area. Our results showed that (i) SFSV is highly prevalent with 71.9% (50.7-84.9% depending on the region) in Greece and 60.2% (40.0-72.6%) in Cyprus; (ii) TOSV ranked second with 4.4% (0-15.4%) in Greece and 8.4% (0-11.4%) in Cyprus; (iii) Salehabad viruses (Arbia and Adana) displayed also substantial prevalence rates in both countries with values ranging from 0-22.6% depending on the region and on the virus strain used in the test. These results demonstrate that circulation of viruses transmitted by sand flies can be estimated qualitatively using dog sera. As reported in other regions of the Mediterranean, these results indicate that it is time to shift these viruses from the "neglected" status to the "priority" status in order to stimulate studies aiming at defining and quantifying their medical and veterinary importance and possible public health impact. Specifically, viruses belonging to the Sandfly fever Sicilian complex should be given careful consideration. This calls for implementation of direct and indirect diagnosis in National reference centers and in hospital microbiology laboratories and systematic testing of unelucidated febrile illness and central and peripheral nervous system febrile manifestations.

Challenges in laboratory diagnosis of acute viral central nervous system infections in the era of emerging infectious diseases: the syndromic approach

INTRODUCTION

Many acute viral infections of the central nervous system (CNS) remain without etiological diagnosis. Specific treatment is available for only few of them; however, accurate diagnosis is essential for patient's life and public health.

AREAS COVERED

In the current article, the main parameters playing a role for a successful etiological diagnosis of acute CNS infections are analysed and the syndromic approach based on clinical and demographic data combined with surrogated indicators is discussed. For the development of a relevant test panel, knowledge on the microbes causing CNS infections in a particular geographic region is essential. The modern screening strategies covering a large panel of potential causative agents are described. Examples of the successful application of next generation sequencing in the identification of etiological agents, including novel and emerging viruses, are given. Expert commentary: Knowledge on epidemiology of the viruses, expertise on syndromic grouping of the etiological agents and advances in technology enable the laboratory diagnosis of acute CNS infections, and the rapid identification, containment and mitigation of probable outbreaks.

[Molecular epidemiology of phlebovirus in four provinces in Morocco]

Sandflies are vectors of protozoa, viruses, and bacteria. To investigate the transmission of phleboviruses, a total of 8753 sandflies were collected in four foci of leishmania. A total of 16 distinct species were morphologically identified. Nested-PCR and cell culture screening for phleboviruses, using an assay targeting the polymerase gene, showed positive results for 19 pools of sandflies. Sequencing of the corresponding products confirmed the results and allowed identification of Toscana virus exclusively. Corresponding sandfly species originated from four different foci, and were different from those commonly reported in the literature. Sequence analysis shows that the Moroccan Toscana viruses belong to genotype B and appear close to the Toscana viruses isolated in France and Spain. This study reported the existence of the virus in the north, center and south of the country. The abundance and diversity of sandflies in Morocco, Mediterranean climate, would support the continuous circulation of Toscana virus in our country, posing a potential risk of emergence of these arboviruses.

Extensive Recruitment of Plasma Blasts to the Cerebrospinal Fluid in Toscana Virus Encephalitis

An unexpectedly extensive recruitment of B cells and plasma blasts to the cerebrospinal fluid (CSF) in a patient with Toscana virus (TOSV) encephalitis is described. Acute infection by TOSV was demonstrated by serological methods and by detection of TOSV-specific nucleic acid in the CSF by real-time polymerase chain reaction and sequencing.

Phlebovirus infection in Greece: a case report

BACKGROUND

Sandfly-transmitted phleboviruses cause to humans an asymptomatic or mild infection to severe meningitis or encephalitis. Phleovirus infections are common in the Mediterranean countries during the summertime when sandflies are active. It is estimated that several cases remain undiagnosed.

DESCRIPTION OF CASE

In July 2013, a 45-year-old Greek male, was admitted to the General Hospital of Florina in northwestern Greece with two-day history of fever, myalgia, arthralgia, mild headache, and hemorrhagic exanthema. A serum sample obtained from the patient on the 6(th) day of illness was tested negative for West Nile virus infection. Instead, high titers of IgM and IgG antibodies against Toscana virus (TOSV) were detected, with low titers against sandfly fever Naples virus and no reactivity against sandfly fever Sicilian and Cyprus viruses, suggesting that the causative agent was TOSV or other phlebovirus with antigenic similarity to TOSV.

CONCLUSION

Phleboviruses have to be included in the differential diagnosis of acute summer febrile cases, accompanied or not by neurological symptoms. Effort has to be paid to test clinical samples during the first days of the disease when the virus is detectable by molecular or isolation methods, in order to elucidate the complex epidemiology of phleboviruses in the Mediterranean area. Hippokratia 2015; 19 (2):189-191.

Phlebovirus infections in Greece

Sandfly fever viruses are endemic in the Mediterranean region causing to humans asymptomatic or mild infections to severe neurological syndromes. In order to investigate the epidemiology of phlebovirus infections in Greece, samples from 499 patients with acute febrile illness (50.2% accompanied by neurological symptoms) were tested during 2010-2014 by serological and molecular methods. Phlebovirus infection was detected in 40 (8%) patients, 25 of them presenting acute neurological infection. Most cases were observed in the summer, with a peak in August. Increased number of cases was observed in 2013, and three of them were observed in Athens. Toscana virus lineage C RNA was detected in one encephalitis case, while the serological results showed that most cases were caused by phleboviruses belonging to the sandfly fever Naples virus serocomplex. This study provided the first insight into the epidemiology of phleboviral disease in Greece.

Laboratory and surveillance studies following a suspected Dengue case in Greece, 2012

OBJECTIVES

To describe the laboratory assays used to investigate a suspected dengue case in summer 2012 in western Greece and to report the public health response.

DESIGN OF METHODS

Samples from the patient were tested for detection of Dengue virus (DENV) antibodies, NS1 antigen and RNA. Public health professionals interviewed residents of the village, and blood samples taken from 132 persons were tested for antibodies for DENV and West Nile virus (WNV). Samples from 10 persons who reported symptoms in the prior 15 days (including 3 persons who had fever at the time of sampling) were tested for DENV, WNV and additional arboviruses. Entomological missions were organized in the area of potential exposure to investigate the presence of competent DENV vectors.

RESULTS

Based on a combination of serological and molecular methods, DENV infection was excluded, and the problems in the serology, especially in the DENV NS1 antigen, were attributed to interfering factors. A 6.1% WNV seroprevalence was detected in the region, and phlebovirus IgM and IgG antibodies were detected in two of three persons who had fever at the time of sampling. Aedes albopictus adult mosquitoes were present in the region.

CONCLUSIONS

A multi-disciplinary field and laboratory investigation showed no evidence of DENV infection. There is a need for industries to improve the immunometric assays to avoid interference with rheumatoid or other factors, and increased awareness is needed for the evaluation of the diagnostic assays. The high WNV seroprevalence in the investigated region highlights the need for strengthening awareness on vector borne diseases. The presence of Ae. albopictus suggests that the possibility of introduction of DENV exists, and preparedness plans are needed.

Serological and molecular detection of Toscana and other Phleboviruses in patients and sandflies in Tunisia

Background

Our aim is to detect the infection by Toscana virus (TOSV) and other Phleboviruses in the sera and cerebro-spinal fluid (CSF) of patients with meningitis in Tunisia. We examined various species of phlebotomus present in Tunisia to determine whether or not a direct relationship exists between cases of meningitis and the viruses circulating in the insect vectors.

Methods

Patients with the meningeal syndrome were tested for anti-TOSV IgM and IgG using an indirect Enzyme-Linked Immunosorbent Assay (ELISA) and for the presence of TOSV and other Phleboviruses using a RT-PCR test.

An entomological study was carried out using CDC light traps to trap sandflies in different bioclimatic zones of Tunisia. Collected sandflies were tested by RT-PCR for the presence of TOSV and other Phleboviruses and subsequently by viral isolation on Vero cells.

Results

Of 263 patients were tested using ELISA of which 12.16% (n = 32/263) were IgM positive for anti TOSV. Of these 32 patients, 78% (n = 25/32) were IgG positive. 12.86% (n = 18/140) of the CSF samples tested by RT-PCR were positive for the Toscana virus.

One CSF sample tested by RT-PCR revealed the presence of Sandfly Fever Sicilian Virus (SFSV). The Punique virus was identified in one sandfly pool.

Conclusions

This study confirms, for the first time, that TOSV is involved in a neurological disorder in North Africa. The incidence of this involvement in Tunisia conforms with observations made in other Mediterranean countries. Moreover, for the first time, a molecular approach was used to detect SFSV in a Tunisian patient displaying neurological symptoms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0598-9) contains supplementary material, which is available to authorized users.