Experimental mumps labyrinthitis in monkeys (Macaca irus)--immunohistochemical and ultrastructural studies

Area of Science:

• Otolaryngology
• Virology
• Pathology

Background:

• Mumps virus can cause neurological complications, including hearing loss.
• The specific pathological mechanisms of mumps virus affecting the inner ear are not fully understood.

Purpose of the Study:

• To investigate the pathological effects of mumps virus infection on the inner ear of non-human primates.
• To characterize the cellular and ultrastructural changes in the cochlea following mumps virus inoculation.

Main Methods:

• Three cynomolgus monkeys (Macaca irus) were inoculated with mumps virus into the cochlea.
• Inner ear tissues were examined using immunofluorescent microscopy and transmission electron microscopy after 14 days.
• Serological tests were performed to confirm viral infection via antibody titers.

Main Results:

• Viral antigens were detected in the stria vascularis using immunofluorescent microscopy.
• Ultrastructural analysis revealed significant pathological changes in the organ of Corti and stria vascularis.
• Outer hair cells were more severely affected than inner hair cells; stria vascularis marginal and intermediate cells were also impacted, with some marginal cells shedding virions.

Conclusions:

• Mumps virus infection leads to acute labyrinthitis with characteristic pathological changes in the cochlea.
• The observed changes in monkeys resemble those seen in guinea pigs, supporting their role as specific features of mumps labyrinthitis.
• This study provides valuable insights into the pathogenesis of mumps virus-induced hearing impairment.