Seroprevalence of sand fly fever Sicilian virus in blood donors in mainland Portugal

Abstract Background Sicilian virus (SFSV), a phlebovirus transmitted by sand flies, is an understudied arbovirus in the Mediterranean region, with limited data on its epidemiology and human health impact. This study aimed to estimate the seroprevalence of SFSV among blood donors in mainland Portugal...

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Main Authors: Rafael Rocha, Elif Kurum, Nazli Ayhan, Rémi Charrel, Carla Maia
Format: Article
Language:English
Published: BMC 2025-07-01
Series:Parasites & Vectors
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Online Access:https://doi.org/10.1186/s13071-025-06885-x
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author Rafael Rocha
Elif Kurum
Nazli Ayhan
Rémi Charrel
Carla Maia
author_facet Rafael Rocha
Elif Kurum
Nazli Ayhan
Rémi Charrel
Carla Maia
author_sort Rafael Rocha
collection DOAJ
description Abstract Background Sicilian virus (SFSV), a phlebovirus transmitted by sand flies, is an understudied arbovirus in the Mediterranean region, with limited data on its epidemiology and human health impact. This study aimed to estimate the seroprevalence of SFSV among blood donors in mainland Portugal and explore associations with sociodemographic factors and exposure to other sand-fly-borne pathogens. Methods A cross-sectional study was conducted using serum samples from 800 blood donors collected between February and June 2022. The study sample was selected from a previously established cohort designed for Leishmania seroprevalence assessment. The microneutralization technique was employed to detect anti-SFSV antibodies. Sociodemographic data were obtained from self-administered questionnaires. Associations between SFSV seropositivity and Toscana virus (TOSV)/Leishmania seropositivity or sociodemographic variables were explored using univariate analysis and multivariate logistic regression. Results Overall, the estimated national true seroprevalence of SFSV was 4.7% (95% CI 3.4–6.3%). Regional seroprevalence varied significantly, with the highest rates (up to 11.9%) observed in the Algarve, Alentejo, and Grande Lisboa regions, respectively. In univariate analysis, SFSV seropositivity was not significantly associated with sex, age, dog ownership, or positive serology for TOSV or Leishmania. In multivariate analysis, geographic area of residence was the only independent factor associated with seropositivity (adjusted odds ratio 3.05; 95% CI 1.85–5.02; p < 0.001). Discussion TThis study represents the first nationwide SFSV seroprevalence estimate in Portugal, revealing wider circulation than previously recognized. The lack of association with TOSV or Leishmania seropositivity could suggest the involvement of distinct vector species. Conclusions Given the observed geographic clustering, SFSV should be considered in the differential diagnosis of undifferentiated febrile syndromes, particularly in endemic regions during peak sand fly activity. Further research is needed to identify specific vectors, improve diagnostic capabilities, and assess the clinical impact of SFSV infections in Portugal. Graphical abstract
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spelling doaj-art-be3a04805b074b3fa8f293aa990ca1a92025-08-20T04:01:25ZengBMCParasites & Vectors1756-33052025-07-0118111010.1186/s13071-025-06885-xSeroprevalence of sand fly fever Sicilian virus in blood donors in mainland PortugalRafael Rocha0Elif Kurum1Nazli Ayhan2Rémi Charrel3Carla Maia4Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa (UNL)Unité des Virus Émergents (UVE; Aix-Marseille Univ, Università di Corsica, IRD 190, Inserm 1207, IRBA)Unité des Virus Émergents (UVE; Aix-Marseille Univ, Università di Corsica, IRD 190, Inserm 1207, IRBA)Unité des Virus Émergents (UVE; Aix-Marseille Univ, Università di Corsica, IRD 190, Inserm 1207, IRBA)Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa (UNL)Abstract Background Sicilian virus (SFSV), a phlebovirus transmitted by sand flies, is an understudied arbovirus in the Mediterranean region, with limited data on its epidemiology and human health impact. This study aimed to estimate the seroprevalence of SFSV among blood donors in mainland Portugal and explore associations with sociodemographic factors and exposure to other sand-fly-borne pathogens. Methods A cross-sectional study was conducted using serum samples from 800 blood donors collected between February and June 2022. The study sample was selected from a previously established cohort designed for Leishmania seroprevalence assessment. The microneutralization technique was employed to detect anti-SFSV antibodies. Sociodemographic data were obtained from self-administered questionnaires. Associations between SFSV seropositivity and Toscana virus (TOSV)/Leishmania seropositivity or sociodemographic variables were explored using univariate analysis and multivariate logistic regression. Results Overall, the estimated national true seroprevalence of SFSV was 4.7% (95% CI 3.4–6.3%). Regional seroprevalence varied significantly, with the highest rates (up to 11.9%) observed in the Algarve, Alentejo, and Grande Lisboa regions, respectively. In univariate analysis, SFSV seropositivity was not significantly associated with sex, age, dog ownership, or positive serology for TOSV or Leishmania. In multivariate analysis, geographic area of residence was the only independent factor associated with seropositivity (adjusted odds ratio 3.05; 95% CI 1.85–5.02; p < 0.001). Discussion TThis study represents the first nationwide SFSV seroprevalence estimate in Portugal, revealing wider circulation than previously recognized. The lack of association with TOSV or Leishmania seropositivity could suggest the involvement of distinct vector species. Conclusions Given the observed geographic clustering, SFSV should be considered in the differential diagnosis of undifferentiated febrile syndromes, particularly in endemic regions during peak sand fly activity. Further research is needed to identify specific vectors, improve diagnostic capabilities, and assess the clinical impact of SFSV infections in Portugal. Graphical abstracthttps://doi.org/10.1186/s13071-025-06885-xBlood donorsPhlebovirusPortugalSeroprevalenceSicilian virus
spellingShingle Rafael Rocha
Elif Kurum
Nazli Ayhan
Rémi Charrel
Carla Maia
Seroprevalence of sand fly fever Sicilian virus in blood donors in mainland Portugal
Parasites & Vectors
Blood donors
Phlebovirus
Portugal
Seroprevalence
Sicilian virus
title Seroprevalence of sand fly fever Sicilian virus in blood donors in mainland Portugal
title_full Seroprevalence of sand fly fever Sicilian virus in blood donors in mainland Portugal
title_fullStr Seroprevalence of sand fly fever Sicilian virus in blood donors in mainland Portugal
title_full_unstemmed Seroprevalence of sand fly fever Sicilian virus in blood donors in mainland Portugal
title_short Seroprevalence of sand fly fever Sicilian virus in blood donors in mainland Portugal
title_sort seroprevalence of sand fly fever sicilian virus in blood donors in mainland portugal
topic Blood donors
Phlebovirus
Portugal
Seroprevalence
Sicilian virus
url https://doi.org/10.1186/s13071-025-06885-x
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AT remicharrel seroprevalenceofsandflyfeversicilianvirusinblooddonorsinmainlandportugal
AT carlamaia seroprevalenceofsandflyfeversicilianvirusinblooddonorsinmainlandportugal