https://doi.org/10.1177/0003489419866219 Annals of Otology, Rhinology & Laryngology 1–5 © The Author(s) 2019 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/0003489419866219 journals.sagepub.com/home/aor Case Report Introduction West Nile virus (WNV) is a neurotropic mosquito-borne virus of the genus Flavivirus that circulates between birds (the amplifying hosts) and mosquitoes (mainly Culex pipi- ens) feeding on birds. Humans and other mammals (espe- cially horses) are considered accidental dead-end hosts. 1 WNV was first isolated in humans in Uganda in 1937. 2 The virus has spread in the last 20 years, also becoming common in Europe, the Middle East, North America, and East Asia, and causing disease outbreaks. 3-5 Although the total number of WNV cases differ from year to year, in the USA more than 2500 cases were reported to the Centers for Disease Control and Prevention (CDC) in 2018, confirming that WNV is the leading cause of arboviral diseases in this continental area. 6 Furthermore, in Europe, over 2080 WNV cases and 180 deaths were reported to the European CDC in 2018, exceeding, by far, the total number from the previous 7 years (n = 1832); compared to 2017, there was a 7.2-fold increase. 7 In Italy, WNV is now considered endemic in sev- eral regions, and the infectious peak usually occurs in August and September. 8 In most cases, humans infected with WNV are asymp- tomatic, but the infection can become clinically manifest – usually with flu-like symptoms – in approximately 20% of cases. 9 WNV infection can develop as a neuroinvasive dis- ease in less than 1% of patients, especially among the elderly or immunocompromised. 10 The fatality rate for neu- roinvasive WNV disease has been estimated at around 20%; patients who survive can develop severe and long-term neu- rological sequelae. 11 Sensorineural hearing loss (SNHL) has occasionally been reported in association with WNV infection. Here we describe two new cases of SNHL with balance disorders caused by WNV infection. For the first time, these patients’ vestibular function was also investigated using videonys- tagmography (VNG). Both patients gave their written per- mission for clinical case publication. Data were examined in accordance with Italian privacy and sensitive data laws as well as the in-house regulations of Padova University’s Otolaryngology Section. 866219AOR XX X 10.1177/0003489419866219Annals of Otology, Rhinology & LaryngologyParrino et al case-report 2019 1 Department of Neuroscience DNS, Otolaryngology Section, Padova University, Padova, Italy 2 Unit of Tropical and Infectious Diseases, Azienda Ospedaliera- Padova University, Padova, Italy Corresponding Author: Gino Marioni, MD, Department of Neuroscience DNS, Otolaryngology Section, University of Padova, Padova, Italy. Email: gino.marioni@unipd.it Cochlear-Vestibular Impairment due to West Nile Virus Infection Daniela Parrino, MD 1 , Giuseppe Brescia, MD 1 , Maria Vittoria Trimarchi, MD 1 , Giulia Tealdo, MD 1 , Lolita Sasset, MD 2 , Anna Maria Cattelan, MD 2 , Roberto Bovo, MD 1 , and Gino Marioni, MD 1 Abstract Objectives: West Nile virus (WNV) has been spreading over the last 20 years. Human infection is asymptomatic in most cases. When the disease becomes clinically manifest, it may involve a range of issues, from a mild infection with flu-like symptoms to a neuroinvasive disease. Albeit rarely, WNV-associated sensorineural hearing loss (SNHL) has also been reported. Here we describe two new cases of SNHL and balance impairment caused by WNV infection. Methods: The patients were investigated with repeated audiometric tests and, for the first time, videonystagmography was also used. Results: Unlike findings in the few other published cases, an improvement in audiometric thresholds and vestibular function was documented in both of our patients. Conclusions: In the light of our findings, a prospective study would be warranted on a large series of patients with WNV infection in order: (i) to better define the epidemiology of the related cochlear-vestibular involvement; and (ii) to elucidate the virus-related changes to peripheral and central auditory and vestibular functions. Keywords West Nile virus, bilateral sensorineural hearing loss, cochlear, disorders of equilibrium, vestibular