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Experimental rabies in skunks: persistence of virus in denervated muscle at the inoculation site
Abstract:
Striped skunks (Mephitis mephitis) were inoculated into the denervated abductor digiti quinti muscle with street rabies virus. They were killed at various times after inoculation and several tissues were examined by immunofluorescence and light microscopy. Muscle at the inoculation site was examined electron microscopically. Rabies antigen was detected in muscle fibers first on day 7 and persisted until day 28. Light and electron microscopic lesions at the inoculation site included atrophic and degenerating muscle fibers and a few focal and regional endomysial accumulations of macrophages, lymphocytes and plasma cells. Scattered myocytes contained bodies of matrix, virions and anomalous tubular structures on electron microscopic examination. The results indicate that replication of rabies virus may occur in infected muscle fibers at the inoculation site until 28 days after exposure. This could contribute to variations in the incubation period for the first two to three months after exposure. However, the results do not support the contention that virus is contained in striated muscle cells throughout the long incubation periods.
Insights
Rabies virus replicates in striped skunk muscle fibers for up to 28 days post-exposure. This muscle replication may influence rabies incubation periods but doesn
Area of Science:
- Veterinary Virology
- Pathology
- Wildlife Disease
Background:
- Rabies virus (RV) poses a significant threat to wildlife and public health.
- Understanding the early pathogenesis of RV in animal models is crucial for disease control.
Purpose of the Study:
- To investigate the early replication and pathological changes of rabies virus in the muscle tissue of striped skunks (Mephitis mephitis).
- To determine the duration of rabies virus presence and replication within muscle fibers following inoculation.
Main Methods:
- Striped skunks were inoculated with street rabies virus in the abductor digiti quinti muscle.
- Tissues were examined using immunofluorescence, light microscopy, and electron microscopy at various time points.
- Muscle tissue at the inoculation site was analyzed for viral antigen and pathological alterations.
Main Results:
- Rabies antigen was detected in muscle fibers from day 7 to day 28 post-inoculation.
- Microscopic examination revealed muscle fiber degeneration and inflammatory cell infiltration at the inoculation site.
- Electron microscopy identified viral particles (virions) and associated structures within myocytes.
Conclusions:
- Rabies virus replicates within infected muscle fibers at the inoculation site for at least 28 days.
- Early muscle replication may contribute to variability in rabies incubation periods.
- The findings do not support the hypothesis that rabies virus is sequestered in striated muscle cells during prolonged incubation.