Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

Volume 16, Number 6—June 2010

Letter

Toscana Virus Infection Imported from Elba into Switzerland

On This Page

Figures

Suggested citation for this article

To the Editor: Toscana virus (TOSV) is a serotype of Sandfly fever Naples virus (SFNV) within the family Bunyaviridae and the genus Phlebovirus. TOSV is transmitted to humans by sandflies (Phlebotomus spp.) and is a prominent cause of aseptic meningitis in Mediterranean countries (1). In Italy, for populations living in rural areas and persons engaging in outdoor activities, the highest risk for acquiring TOSV is from August through October (1). TOSV infections should therefore be considered in travelers returning from the Mediterranean area who have fever and signs of meningitis. Laboratory diagnosis of TOSV infections is often limited to the detection of immunoglobulin (Ig) M and IgG because of the short period of viremia and the low amount of virus in the cerebrospinal fluid (CSF) during the acute phase (2). We report a reverse transcription–PCR (RT-PCR)–confirmed TOSV infection acquired on the island of Elba that was then imported into Switzerland.

A 17-year-old man was referred to Basel University Medical Clinic, Liestal, Switzerland, in August 2009 with headache, recurrent episodes of vomiting, photophobia and phonophobia, and an elevated temperature of 38.1°C. The patient had returned to Switzerland from a vacation on the island of Elba, Italy, 14 days before. He recalled that he had received multiple insect bites on the beach. Cardiopulmonary and neurologic examination showed tachycardia and nuchal rigidity. Results of a complete blood count and liver and kidney function tests showed no abnormalities. CSF analysis showed lymphocytic pleocytosis (47 cells/µL), and aseptic meningitis of viral origin was suspected. Empirical treatment with acyclovir (2.3 g/day) was started for the first 48 hours. The results of a PCR for herpesviruses were negative in the CSF sample, and serologic testing showed no evidence of acute infection with herpesviruses. CSF, urine, and blood cultures showed negative results for fungi and bacteria, including mycobacteria. The patient did not show signs of immune deficiency.

Figure

Thumbnail of Bayesian phylogenetic tree of Toscana virus (TOSV) and Sandfly fever Naples virus (SFNV) strains. For each sequence used, GenBank accession number, strain designation, and strain origin are shown. Phylognetic analysis was performed by using MrBayes 3.0 program (4) with a general time reversible substitution model. Substitution rates were assumed to follow a gamma plus invariants distribution. Three heated chains and a single cold chain were used in all Markov Chain Monte Carlo analy

Figure. Bayesian phylogenetic tree of Toscana virus (TOSV) and Sandfly fever Naples virus (SFNV) strains. For each sequence used, GenBank accession number, strain designation, and strain origin are shown. Phylognetic analysis was...

Serum and CSF samples were sent to the Bernhard-Nocht-Institute for Tropical Medicine in Germany for SFNV diagnostics. Results of immunofluorescent assays for TOSV and SFNV were positive with IgM titers of 1,280 and 160, respectively (cut-off 20) and IgG titers of 5,120 and 640, respectively (cut-off 20). Real-time RT-PCRs for detection of TOSV and SFNV were performed using the CSF sample according to a recently published protocol (3). A positive result was obtained for TOSV, and the PCR result was confirmed by sequencing the PCR product. Phylogenetic analysis demonstrated that the TOSV from Elba clustered with the TOSV A lineage (Figure). Attempts to isolate TOSV from the CSF sample in cell culture failed. The patient was afebrile on the second day of hospitalization, headache vanished on the third day, and he was discharged on day 5 restitutio ad integrum (fully recovered).

This report demonstrates the presence of TOSV on the island of Elba by molecular detection and typing. This finding is in agreement with previous serologic reports on imported TOSV infections from this area into central Europe (5,6). However, because of serologic cross-reactivity, serologic tests are usually not able to clearly discriminate between TOSV and other SFNV infections (2).

Real-time RT-PCR is the most appropriate tool for the differentiation of TOSV from other SFNV infections and enables molecular typing of amplified sequences. The Bayesian phlyogenetic tree calculated with the short PCR fragment (111 bp, GenBank accession no. GU270841) of the nucleocapsid coding sequence (Figure) shows the same topology of the main clades when compared with trees obtained with the complete N coding sequence (7,8). The assignment of the TOSV from Elba to lineage A (Figure) is consistent with results of previous studies, demonstrating that this is the dominant genotype of TOSV in mainland Italy and the island of Sardinia (8).

The presence of TOSV A on the island of Elba is a major public health issue for the local population and for the >2 million tourists that visit Elba every year (9). Given the incidence of TOSV infections in other surrounding Mediterranean countries, one could assume that the virus is present in other islands of the Mediterranean, posing a public health problem for the resident population and tourists alike. Molecular and serologic surveillance studies in Mediterranean countries could identify potential high risk areas for TOSV infections to help prevent exposure of local residents and tourists to the virus. Moreover, the risk of transfusion-associated transmission of arboviruses in European countries should be addressed.

Martin Gabriel, Christiane Resch, Stephan Günther, and Jonas Schmidt-ChanasitComments to Author 
Author affiliations: Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany (M. Gabriel, S. Günther, J. Schmidt-Chanasit); Basel University Medical Clinic, Liestal, Switzerland (C. Resch)

Acknowledgment

We thank Rebecca Stanway and Petra Herzog for critical reading of the manuscript.

References

  1. Charrel RN, Gallian P, Navarro-Mari JM, Nicoletti L, Papa A, Sánchez-Seco MP, Emergence of Toscana virus in Europe. Emerg Infect Dis. 2005;11:165763.PubMed
  2. Dionisio D, Esperti F, Vivarelli A, Valassina M. Epidemiological, clinical and laboratory aspects of sandfly fever. Curr Opin Infect Dis. 2003;16:3838. DOIPubMed
  3. Weidmann M, Sanchez-Seco MP, Sall AA, Ly PO, Thiongane Y, MM, Rapid detection of important human pathogenic Phleboviruses. J Clin Virol. 2008;41:13842. DOIPubMed
  4. Ronquist F, Huelsenbeck JP. Mrbayes 3: Bayesian phylogenetic inference under mixed models. Bioinformatics. 2003;19:15724. DOIPubMed
  5. Dobler G, Treib J, Haass A, Frösner G, Woesner R, Schimrigk K. Toscana virus infection in German travellers returning from the Mediterranean. Infection. 1997;25:325. DOIPubMed
  6. Sonderegger B, Hachler H, Dobler G, Frei M. Imported aseptic meningitis due to Toscana virus acquired on the island of Elba, Italy, August 2008. Euro Surveill. 2009;14:pii=19079.
  7. Charrel RN, Moureau G, Temmam S, Izri A, Marty P, Parola P, Massilia virus, a novel Phlebovirus (Bunyaviridae) isolated from sandflies in the Mediterranean. Vector Borne Zoonotic Dis. 2009;9:51930. DOIPubMed
  8. Collao X, Palacios G, Sanbonmatsu-Gámez S, Pérez-Ruiz M, Negredo AI, Navarro-Marí JM, Genetic diversity of Toscana virus. Emerg Infect Dis. 2009;15:5747. DOIPubMed
  9. Towards regional economic development 2006/2010. Tourism and innovations objectives and instruments [in Italian]. 2006 [cited 2010 Apr 1]. http://www.provincia.livorno.it/economia/turismo/forumturismo2006/FormatLivorno4aprile2006.pdf

Figure

Suggested citation for this article: Gabriel M, Resch C, Günther S, Schmidt-Chanasit J. Toscana virus infection imported from Elba into Switzerland [letter]. Emerg Infect Dis [serial on the Internet]. 2010 Jun [date cited]. http://wwwnc.cdc.gov/eid/article/16/6/09-1763

DOI: 10.3201/eid1606.091763

Related Links

Table of Contents – Volume 16, Number 6—June 2010

Comments to the Authors

Please use the form below to submit correspondence to the authors or contact them at the following address:

Jonas Schmidt-Chanasit, Department of Virology, Clinical Virology LaboratoryBernhard Nocht Institute for Tropical Medicine, Bernhard Nocht Strasse 74, D-20359 Hamburg, Germany

character(s) remaining.

Comment submitted successfully, thank you for your feedback.

Comments to the EID Editors

Please contact the EID Editors via our Contact Form.

TOP