Prevalence and characterization of West Nile virus infections among people living with HIV in Northern Italy: a sero-repository analysis
5 affiliations
- 1Department of Clinical and Experimental Sciences, Unit of Infectious and Tropical Diseases, University of Brescia and ASST Spedali Civili di Brescia, Brescia, 25123 Italy
- 2Department of Infectious-Tropical Diseases and Microbiology, IRCCS Ospedale Sacro Cuore Don Calabria, Negrar di Valpolicella, Verona, Italy
- 3Unit of Infectious and Tropical Diseases, ASST Spedali Civili di Brescia, Brescia, 25123 Italy
- 4Unit of Biostatistics and Bioinformatics, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
- 5Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden
Abstract
Background: West Nile virus (WNV) is increasingly reported in Italy, yet its population prevalence remains uncertain. People living with HIV (PLWH) may be at increased risk of WNV severe manifestations, including neuroinvasive disease. This study assessed the seroprevalence and factors associated with WNV seropositivity among PLWH in a large Northern Italian cohort.
Methods: This retrospective single-center study included all PLWH followed at the Brescia HIV Outpatient Clinic with at least one serum sample collected in 2022 and stored in the institutional sero-repository. Samples were screened for WNV antibodies using ELISA; reactive or borderline samples were confirmed by immunofluorescence assay for IgG and IgM and further characterized by microneutralization assays to differentiate WNV from USUV infection. Associations with seropositivity were evaluated using univariate logistic regression.
Results: Among 2,843 PLWH, 76.2% were male, the mean age was 54.1 (± 10.5), and 87.2% were of Italian origin. Most participants had virologically suppressed HIV infection and were receiving stable antiretroviral therapy (94.2%). WNV serological screening by ELISA identified IgG positivity in 176 participants (6.2%). Of these, 166 tested positive by immunofluorescence assay. Neutralization assays subsequently confirmed WNV seropositivity in 86 participants (3.0%), USUV seropositivity in 12 (0.6%), and dual WNV/USUV neutralizing antibody positivity in 6 (0.2%). No neuroinvasive diseases were reported. Compared with seronegative individuals, seropositive participants were less frequently male (p = 0.001), younger (p < 0.001) and differed significantly by geographic origin (p < 0.001), with a higher prevalence among PLWH born outside Europe. In logistic regression analyses, geographic origin was strongly associated with seropositivity: participants from Africa (OR 21.22, 95% CI 12.49–36.03), Asia (OR = 23.31, 95% CI: 10.19–53.31), and the Americas (OR 19.16, 95% CI 9.45–38.83) had markedly higher odds compared with participants of Italian origin (all p < 0.001).
Discussion: This is, to our knowledge, the first study evaluating WNV seroprevalence among PLWH. Seroprevalence was higher than that reported in comparable European blood donor populations. In this largely virologically suppressed, stably treated outpatient cohort, no severe manifestations were observed and symptoms were infrequently recalled.
Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s15010-026-02919-3.
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BibTeX
@article{tiecco2026prevalence,
title = {{Prevalence and characterization of West Nile virus infections among people living with HIV in Northern Italy: a sero-repository analysis}},
author = {Giorgio Tiecco and Concetta Castilletti and Alessandro Pavesi and Silvia Accordini and Natasha Gianesini and Jacopo Logiudice and Rebeca Passarelli Mantovani and Benedetta Rossi and Lorena Maria Chesini and Stefano Calza and Elena Raffetti and Federico Giovanni Gobbi and Lina Rachele Tomasoni and Francesco Castelli and Eugenia Quiros-Roldan},
journal = {Infection},
year = {2026},
month = aug,
doi = {10.1007/s15010-026-02919-3},
url = {https://doi.org/10.1007/s15010-026-02919-3},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Prevalence and characterization of West Nile virus infections among people living with HIV in Northern Italy: a sero-repository analysis
AU - Giorgio Tiecco
AU - Concetta Castilletti
AU - Alessandro Pavesi
AU - Silvia Accordini
AU - Natasha Gianesini
AU - Jacopo Logiudice
AU - Rebeca Passarelli Mantovani
AU - Benedetta Rossi
AU - Lorena Maria Chesini
AU - Stefano Calza
AU - Elena Raffetti
AU - Federico Giovanni Gobbi
AU - Lina Rachele Tomasoni
AU - Francesco Castelli
AU - Eugenia Quiros-Roldan
PY - 2026
DA - 2026/08/11
JO - Infection
DO - 10.1007/s15010-026-02919-3
UR - https://doi.org/10.1007/s15010-026-02919-3
AB - Background: West Nile virus (WNV) is increasingly reported in Italy, yet its population prevalence remains uncertain. People living with HIV (PLWH) may be at increased risk of WNV severe manifestations, including neuroinvasive disease. This study assessed the seroprevalence and factors associated with WNV seropositivity among PLWH in a large Northern Italian cohort. Methods: This retrospective single-center study included all PLWH followed at the Brescia HIV Outpatient Clinic with at least one serum sample collected in 2022 and stored in the institutional sero-repository. Samples were screened for WNV antibodies using ELISA; reactive or borderline samples were confirmed by immunofluorescence assay for IgG and IgM and further characterized by microneutralization assays to differentiate WNV from USUV infection. Associations with seropositivity were evaluated using univariate logistic regression. Results: Among 2,843 PLWH, 76.2% were male, the mean age was 54.1 (± 10.5), and 87.2% were of Italian origin. Most participants had virologically suppressed HIV infection and were receiving stable antiretroviral therapy (94.2%). WNV serological screening by ELISA identified IgG positivity in 176 participants (6.2%). Of these, 166 tested positive by immunofluorescence assay. Neutralization assays subsequently confirmed WNV seropositivity in 86 participants (3.0%), USUV seropositivity in 12 (0.6%), and dual WNV/USUV neutralizing antibody positivity in 6 (0.2%). No neuroinvasive diseases were reported. Compared with seronegative individuals, seropositive participants were less frequently male (p = 0.001), younger (p < 0.001) and differed significantly by geographic origin (p < 0.001), with a higher prevalence among PLWH born outside Europe. In logistic regression analyses, geographic origin was strongly associated with seropositivity: participants from Africa (OR 21.22, 95% CI 12.49–36.03), Asia (OR = 23.31, 95% CI: 10.19–53.31), and the Americas (OR 19.16, 95% CI 9.45–38.83) had markedly higher odds compared with participants of Italian origin (all p < 0.001). Discussion: This is, to our knowledge, the first study evaluating WNV seroprevalence among PLWH. Seroprevalence was higher than that reported in comparable European blood donor populations. In this largely virologically suppressed, stably treated outpatient cohort, no severe manifestations were observed and symptoms were infrequently recalled. Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s15010-026-02919-3.
SN - 0300-8126
SN - 1439-0973
ER -