Toscana Virus in Spain

Sara Sanbonmatsu-Gámez,Ximena Collao,Francisco Morillas-Márquez,Manuel de la Rosa-Fraile,Antonio Tenorio,José María Navarro-Marí,Mercedes Pérez-Ruiz,María Paz Sánchez-Seco

doi:10.3201/eid1111.050851

Abstract

Toscana virus (TOSV, Phlebovirus, family Bunyaviridae) infection is one of the most prevalent arboviruses in Spain. Within the objectives of a multidisciplinary network, a study on the epidemiology of TOSV was conducted in Granada, in southern Spain. The overall seroprevalence rate was 24.9%, significantly increasing with age. TOSV was detected in 3 of 103 sandfly pools by viral culture or reverse transcription-polymerase chain reaction from a region of the L gene. Nucleotide sequence homology was 99%-100% in TOSV from vectors and patients and 80%-81% compared to the Italian strain ISS Phl.3. Sequencing of the N gene of TOSV isolates from patients and vectors indicated 87%-88% and 100% homology at the nucleotide and amino acid levels, respectively, compared to the Italian strain. These findings demonstrate the circulation of at least 2 different lineages of TOSV in the Mediterranean basin, the Italian lineage and the Spanish lineage.

Highlights

Toscana virus (TOSV, Phlebovirus, family Bunyaviridae) infection is one of the most prevalent arboviruses in Spain
Other seroprevalence studies carried out in northern Europe report lower rates [13], which demonstrates that TOSV infection is endemic in Mediterranean countries
The high seroprevalence rates suggest that the diagnosis of TOSV infection is frequently missed since most cases are mild, as occurs with sandfly fever Sicilian virus (SFSV) and sandfly fever Naples virus (SFNV) infections [6], a severe illness involving the central nervous system develops in only a few patients

Summary

Introduction

Toscana virus (TOSV, Phlebovirus, family Bunyaviridae) infection is one of the most prevalent arboviruses in Spain. Within the objectives of a multidisciplinary network, a study on the epidemiology of TOSV was conducted in Granada, in southern Spain. Sequencing of the N gene of TOSV isolates from patients and vectors indicated 87%–88% and 100% homology at the nucleotide and amino acid levels, respectively, compared to the Italian strain. These findings demonstrate the circulation of at least 2 different lineages of TOSV in the Mediterranean basin, the Italian lineage and the Spanish lineage. One of the objectives of the network is to study TOSV infections in Spain. Vector-based TOSV surveillance is useful in reporting virus activity It provides predictive indicators of transmission activity level associated with elevated human risk.

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Conclusion