West Nile virus (WNV) is a Flavivirus transmitted by mosquitoes and is an emerging public health problem in Europe.1 More than 80% of WNV-infected individuals run an asymptomatic course, whereas those who are symptomatic generally exhibit a flu-like syndrome. Severe neuroinvasive disease (i.e., meningitis, encephalitis, and acute flaccid paralysis) is observed in 1% of infected individuals or 10% of those symptomatic, particularly elderly and immunocompromised subjects.2 A variable diffusion of WNV has been recorded in Europe since 2008, with an alarming recrudescence observed in 2018 when 2083 autochthonous infections were registered. Of those, nearly one-third (576 cases) were reported by Italy.3
As of November 4, 2020, Italy has recorded 68 cases of WNV infection, 45 of which were of neuroinvasive disease.4 As compared with previous years, surveillance data indicate that WNV circulation in mosquitoes, equids, and humans was less intense in Italy during 2020, and in our region (Lombardy), it had a delayed onset.5 Herein, we describe a fatal case of WNV meningoencephalomyelitis observed during the summer in Milan, Italy, in an Egyptian woman who was initially diagnosed as affected by COVID-19.
The American Society of Tropical Medicine and Hygiene has waived the Open Access fee for this article due to the ongoing COVID-19 pandemic.
ECDC, 2019. Epidemiological Update: West Nile Virus Transmission Season in Europe, 2019. Available at: https://ecdc.europa.eu/en/news-events/epidemiological-update-west-nile-virus-transmission-season-europe-2018. Accessed September 8, 2020.
Istituto Superiore di Sanità, 2020. Sorveglianza Integrata del West Nile e Usutu Virus. Available at: Epicentro.iss.it/westnile/bollettino/Bollettino_WND_2020_16.pdf. Accessed November 7, 2020.
Calzolari M 2020. Enhanced West Nile virus circulation in the Emilia-Romagna and Lombardy regions (Northern Italy) in 2018 detected by entomological surveillance. Front Vet Sci 7: 243.
Maury A, Lyoubi A, Pfeiffer-Smadja N, de Broucker T, Meppiel L, 2021. Neurological manifestations associated with SARS-CoV-2 and other coronavirus: a narrative review for clinicians. Rev Neurol 177: 51–64.
Meppiel E On Behalf of the Contributors to the NeuroCOVID Registry 2020. Neurologic manifestations associated with COVID-19: a multicentre registry. Clin Microbiol Infect 27: 458–466.
Lyer NR, McCune WJ, Wallace BI, 2019. West Nile encephalitis mimicking neuropsychiatric lupus in a patient with systemic lupus erythematosus. BMJ Case Rep 12: e229537.
CDC, 2015. Arboviral Diseases, Neuroinvasive and Non-neuroinvasive, Case Definition. Available at: www.cdc.gov/Nndss/conditions/arboviral-diseas-neuroinvasive-and-non-neuroinvasive/case-definitions/2015/. Accessed September 11, 2020.
Istituto Superiore di Sanità, 2020. Sorveglianza Integrata del West Nile e Usutu Virus. Available at: epicentro.iss.it/westnile/bollettino/Bollettino_WND_2020_3.pdf. Accessed August 8, 2020.
Zuin M, Rigatelli G, Roncon L, 2020. Reduction of West Nile virus infections in Italy during 2020 early summer: a secondary ‘COVID-19’ effect? Pathog Glob Health 114: 345–346.