Experimental rabies in skunks: immunofluorescence light and electron microscopic studies

Area of Science:

• Veterinary Virology
• Neuroscience
• Pathology

Background:

• Rabies is a fatal viral disease transmitted by infected animals.
• The transmission routes and cellular mechanisms of rabies virus in striped skunks (Mephitis mephitis) are not fully understood.
• Understanding viral dissemination is crucial for disease control and prevention.

Purpose of the Study:

• To investigate the early sites of rabies virus replication and dissemination in striped skunks.
• To elucidate the cellular mechanisms of rabies virus spread within the central nervous system (CNS) and peripheral nerves.
• To explore the role of muscle cells and neuronal transfer in rabies pathogenesis.

Main Methods:

• Inoculation of striped skunks with street rabies virus in the abductor digiti quinti muscle.
• Detection of viral antigen using immunofluorescence and electron microscopy.
• Examination of viral distribution in muscle, CNS, and peripheral nerve tissues.

Main Results:

• Rabies virus antigen was detected in muscle cells at the inoculation site prior to CNS detection.
• Viral antigen was widespread in neurons throughout the brain, spinal cord, and peripheral nerves in terminal stages.
• Electron microscopy revealed viral particles and replication within neuronal perikarya, dendrites, and muscle fibers.
• Viral budding occurred on various cellular membranes, including neuronal plasma membranes and endoplasmic reticulum.
• Evidence suggests direct transneuronal transfer of virus between adjacent neurons in the CNS.

Conclusions:

• Rabies virus replicates in skunk muscle cells, potentially influencing incubation period.
• Direct transneuronal transfer is a significant mechanism for rabies virus dissemination within the skunk CNS.
• The findings provide insights into rabies pathogenesis and spread in wildlife reservoirs.