Related Experiment Videos
Conjunctival instillation of scrapie in mice can produce disease
J R Scott1, J D Foster, H Fraser
1AFRC and MRC Neuropathogenesis Unit, Institute for Animal Health, Edinburgh, UK.
Abstract:
Mice were infected with one of two strains of scrapie by instilling brain homogenate into the conjunctiva to establish whether infection could be initiated. Of the 55 mice infected with ME7 scrapie, 23 developed clinical disease 323 +/- 8 (mean +/- standard error) days later. Three out of 12 mice infected with 79A scrapie developed disease after 232 +/- 35 days. The ME7 incubation period is similar to that for the oral route of infection. We feel that these results emphasize the need for adequate eye protection when handling tissues infected with spongiform encephalopathies.
Insights
Conjunctival instillation of scrapie brain homogenate can initiate infection in mice. This highlights the importance of eye protection when handling tissues with spongiform encephalopathies.
Area of Science:
- Neuroscience
- Infectious Diseases
- Veterinary Medicine
Background:
- Scrapie is a transmissible spongiform encephalopathy affecting sheep and goats.
- The transmission routes of spongiform encephalopathies are not fully understood.
- Ocular exposure is a potential, yet understudied, route for prion disease transmission.
Purpose of the Study:
- To investigate the potential for scrapie infection initiation via conjunctival instillation in a mouse model.
- To determine the incubation period and disease progression following ocular exposure to scrapie.
Main Methods:
- Mice were inoculated with brain homogenate from two distinct scrapie strains (ME7 and 79A) via conjunctival instillation.
- Clinical signs of disease were monitored, and incubation periods were recorded.
- Survival analysis was performed to compare incubation periods between strains and with known routes.
Main Results:
- Mice infected with ME7 scrapie showed a 41.8% (23/55) clinical disease rate with a mean incubation period of 323 ± 8 days.
- Mice infected with 79A scrapie showed a 25% (3/12) clinical disease rate with a mean incubation period of 232 ± 35 days.
- The incubation period for ME7 via the conjunctival route was comparable to that of the oral route.
Conclusions:
- Conjunctival instillation is an effective route for initiating scrapie infection in mice.
- These findings underscore the necessity of implementing stringent eye protection measures when working with tissues potentially contaminated with spongiform encephalopathies.
- Further research into ocular transmission of prion diseases is warranted.