Early-onset sensorineural hearing loss in Lassa fever

Abstract

Lassa fever (LF) is a viral hemorrhagic disease which affects one-fourth to two million people annually with the fatality rate of about 10,000. It is associated with sensorineural hearing loss (SNHL) usually at the convalescent stage. Recently, cases of SNHL at the acute phase have been reported. This study was done to further investigate the incidence and features of SNHL in acute phase of LF. It is a prospective case-control study of LF patients seen with acute SNHL conducted between July 2007 and April 2009 at Irrua Specialist Teaching Hospital Nigeria. The diagnosis of acute LF was based on the clinical features and detection of IgM antibodies and/or positive Lassa virus-specific reverse transcriptase-polymerase chain reaction using primers S36+ and LVS 339 while SNHL was diagnosed clinically and confirmed with PTA and speech discrimination tests. Patients with other acute febrile illnesses were used as control. Statistical analysis was done using SPSS version 11 and Fisher's exact test while level of significance was set at p < 0.05. Out of the 37 confirmed cases of LF, 5 (13.5%) and none (0%) of the control developed early-onset SNHL (p = 0.03). Forty percent of the cases studied had negative IgM. The audiograms showed involvement at all frequency groups with pure tone average 65-85 dB and the speech discrimination 20-40%. The overall case fatality rate was 27.0%, and for early SNHL cases 60.0% (p > 0.05). The incidence of SNHL in LF infection is about 13.5% and could be a reflection of a worse disease process. There is possibility of direct viral invasion aside immunological reaction as a causative mechanism.

Animal Model of Sensorineural Hearing Loss Associated with Lassa Virus Infection

“…Two mechanisms related to hearing loss resulting from LASV infection have been proposed in the past, a virus-induced immunological injury (4,22) and a virus-mediated injury to the inner ear (23). Little evidence to support these hypotheses existed outside clinical descriptions, which do not allow for evaluation of the inner ear postmortem.…”

Imported Case of Lassa Fever in Sweden With Encephalopathy and Sensorineural Hearing Deficit

“…The underlying neuropathogenesis remains unknown, and both immunological and direct viral cytotoxic mechanisms have been proposed [6, 8, 13]. Lassa virus RNA detected in CSF but not in serum has been documented in 1 previous case of Lassa fever encephalopathy from Nigeria, and persistence of virus in the central nervous system (CNS) was suggested [8].…”

Post-Ebolavirus disease syndrome: what do we know?

“…Sensorineural hearing loss may occur with other hemorrhagic fevers, and was reported in one-third of Lassa virus infections [10,11]. The risk of hearing loss was two-times higher for Bundibugyo ebolavirus survivors as compared to controls, and 50% reported moderate hearing loss [4].…”