THE PATHOGENESIS AND PATHWAY INTO THE CENTRAL NERVOUS SYSTEM AFTER INTRAOCULAR INFECTION OF HERPES SIMPLEX VIRUS TYPE I IN RABBITS

Abstract

Herpes simplex virus (HSV) type I was injected into the right eye of 18-day-old New Zealand albino rabbits and the animals were killed on the fourth and eighth days after inoculation. Longitudinal section of the optic nerves and chiasma showed that both myelinated axons and neuroglial cells crossed at the chiasma. Semi-serial (1 micrometer) and ultrathin sections showed the presence of HSV in both astrocytes and oligodendrocytes, although no particles were seen in the myelinated axons; the infected cells were confined to the medial side of the right optic nerve. HSV travels centropetally along the optic pathway and slowly spreads laterally by cell-to-cell infection. The virus does not appear to kill the astrocytes and oligodendrocytes, and also does not directly damage the myelin sheath.

Spontaneous fatal Human herpesvirus 1 encephalitis in two domestic rabbits (Oryctolagus cuniculus)

“…17,18 Development of latent state of infection has been described for experimental infection in rabbits following corneal and intranasal inoculation. 13,21,30 Characteristic histologic lesions include mononuclear cell inflammation, perivascular inflammation and necrosis, and intranuclear inclusion bodies.…”

“…13,17,18,21,23 Human herpesvirus 1 in rabbits is exclusively neurotropic. The different proposed mechanisms of infection and virus spread into the central nervous system (CNS) in people with HHV encephalitis have been investigated in rabbits.…”

“…30 Neurologic disease can progress to seizures, moribund state, or death with intranasal or intraocular virus inoculation. 17,18,30 Mortality rates vary with inoculation route being the highest for intranasal 545111V DIXXX10.1177/1040638714545111Fatal Human herpesvirus 1 encephalitis in domestic rabbitsde Matos et al…”

“…Following inoculation, the virus migrates through the optic nerve and chiasm to the corpus geniculatum. 17,18 Rabbits can present neurologic signs as early as 2 days postinoculation. Such signs include changes in activity (decreased or increased), ataxia, head jerking movements, and/or circling.…”

“…Such signs include changes in activity (decreased or increased), ataxia, head jerking movements, and/or circling. 13,17,18,21,30 Ptyalism has been described in rabbits following intranasal virus inoculation. 30 Neurologic disease can progress to seizures, moribund state, or death with intranasal or intraocular virus inoculation.…”