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Scrapie infection can be established readily through skin scarification in immunocompetent but not immunodeficient
D M Taylor1, I McConnell, H Fraser
1Institute for Animal Health, Edinburgh, UK.
Abstract:
Scarification of the skin is a possible route of entry for scrapie infectivity in sheep, and for Creutzfeldt-Jakob disease agent in humans within the context of occupational exposure to infected brain in the autopsy room or laboratory. The effectiveness of skin scarification routes as portals of entry for infectivity had not previously been tested experimentally but this study has shown that these are efficient routes for establishing infection in mice using the 139A and ME7 strains of scrapie agent. Scarification had much the same efficiency as inoculation by the intraperitoneal, intravenous or perivenous routes but was not effective in immunocompromised (SCID) mice. It was concluded that replication of infectivity within the lymphoreticular system, which is precluded in SCID mice, is a necessary prerequisite for the development of infection in the central nervous system following inoculation via scarification.
Insights
Skin scarification is an efficient route for prion disease entry in mice, similar to other inoculation methods. This pathway requires a functional lymphoreticular system for central nervous system infection.
Area of Science:
- Neuroscience
- Infectious Diseases
- Prion Biology
Background:
- Prion diseases, such as scrapie in sheep and Creutzfeldt-Jakob disease in humans, can potentially spread through skin exposure.
- Occupational exposure in laboratory or autopsy settings presents a risk for healthcare professionals.
- The efficacy of skin scarification as a route of prion agent entry had not been experimentally validated.
Purpose of the Study:
- To experimentally assess the effectiveness of skin scarification as a portal of entry for prion infectivity.
- To compare the efficiency of scarification with established inoculation routes.
- To investigate the role of the lymphoreticular system in prion disease pathogenesis via skin scarification.
Main Methods:
- Infection of immunocompetent mice with 139A and ME7 scrapie strains via skin scarification.
- Comparison of infection rates following scarification with intraperitoneal, intravenous, and perivenous inoculation.
- Assessment of infectivity in severe combined immunodeficient (SCID) mice following scarification.
Main Results:
- Skin scarification proved to be an efficient route for establishing scrapie infection in mice.
- The efficiency of scarification was comparable to intraperitoneal, intravenous, and perivenous inoculation routes.
- Scarification did not lead to infection in immunocompromised SCID mice.
Conclusions:
- Skin scarification is a viable and efficient route for prion agent entry.
- Replication of infectivity within the lymphoreticular system is essential for subsequent central nervous system infection following scarification.
- These findings highlight the importance of protective measures against skin exposure in prion-related research and healthcare settings.