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Duration and patterns of transmission of Theiler's mouse encephalomyelitis virus infection
D Brownstein1, P Bhatt, R Ardito
1Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510.
Abstract:
The duration and patterns of Theiler's murine encephalomyelitis virus (TMEV) transmission were studied in eight index mice inoculated orally. Transmission was monitored by testing for seroconversion to TMEV in sentinel mice in direct contact with index mice and in other sentinel mice in contact with bedding soiled by index mice. For the first 14 weeks after inoculation, two contact sentinels were housed with each index mouse for 1 week, then replaced with two new sentinels. For the remaining 16 weeks, contact sentinels were changed monthly. All index mice transmitted TMEV continuously (weekly) for 4 to 9 weeks. Thereafter, six index mice transmitted virus intermittently. All index mice ceased transmitting TMEV 7 to 22 weeks post-inoculation. Results obtained from sentinel mice in contact with bedding soiled by index mice were 86% concordant with those using contact sentinel mice. Seven index mice were treated with cyclophosphamide or hydrocortisone 30 weeks post-inoculation. One cyclophosphamide treated mouse reinitiated virus shedding.
Insights
Theiler
Area of Science:
- Virology
- Immunology
- Neuroscience
Background:
- Theiler's murine encephalomyelitis virus (TMEV) is a significant pathogen causing neurological disease in mice.
- Understanding TMEV transmission dynamics is crucial for developing effective control strategies.
- Previous studies have not fully elucidated the prolonged transmission patterns of TMEV.
Purpose of the Study:
- To investigate the duration and patterns of TMEV transmission in an experimental mouse model.
- To assess the efficacy of different sentinel mouse methods for detecting TMEV transmission.
- To evaluate the impact of immunosuppressive agents on TMEV shedding.
Main Methods:
- Oral inoculation of eight index mice with TMEV.
- Monitoring transmission through seroconversion in direct contact sentinel mice and bedding soiled sentinel mice.
- Regular replacement of sentinel mice to capture transmission over 30 weeks.
- Treatment of seven index mice with cyclophosphamide or hydrocortisone at 30 weeks post-inoculation.
Main Results:
- All index mice transmitted TMEV continuously for 4-9 weeks, with intermittent shedding thereafter.
- Transmission ceased between 7 and 22 weeks post-inoculation for all index mice.
- Bedding soiled sentinel mice showed 86% concordance with direct contact sentinel mice.
- One cyclophosphamide-treated mouse reinitiated TMEV shedding after immunosuppression.
Conclusions:
- TMEV can be shed for extended periods, with variable continuous and intermittent patterns.
- Both direct contact and bedding soiled sentinel mice are effective for TMEV transmission monitoring.
- Immunosuppression can potentially reinitiate TMEV shedding in previously infected mice.