Two epizootics of lymphocytic choriomeningitis virus occurring in laboratory mice despite intensive monitoring programs
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Abstract:
Two epizootics of lymphocytic choriomeningitis virus in mice occurred within two months in one research facility consisting of several widely separated rooms. These outbreaks developed despite intensive institutional monitoring policies designed to prevent introduction and spread of lymphocytic choriomeningitis virus. Evidence derived from serological and virological assays and interviews with the concerned investigators suggested that a single transplantable tumor carried in mice may have been responsible for spread of the virus. However, the tumor was not contaminated with lymphocytic choriomeningitis virus at the time of its introduction into the mouse facility. The origin of the virus responsible for the outbreaks was not definitively established although data supported an hypothesis that the virus was introduced into the research facility by a wild or feral mouse. Virus spread from infected mice to humans did not occur, as measured by serological tests. However, a large and valuable animal facility was depopulated for safety reasons. Absorption of sera with lymphocytic choriomeningitis virus antigen proved a necessary and reliable method for confirming specificity of lymphocytic choriomeningitis virus fluorescence-positive reactions.
Insights
Two lymphocytic choriomeningitis virus (LCMV) outbreaks occurred in a research facility despite monitoring. Evidence suggests a transplantable tumor or wild mice may have introduced LCMV, necessitating facility depopulation.
Area of Science:
- Veterinary Medicine
- Virology
- Infectious Disease Epidemiology
Background:
- Lymphocytic choriomeningitis virus (LCMV) poses a significant threat to research animal facilities.
- Despite stringent monitoring, LCMV outbreaks can still occur, leading to substantial disruption and economic loss.
- Understanding LCMV transmission dynamics is crucial for preventing future epizootics.
Purpose of the Study:
- To investigate the cause and transmission of two concurrent LCMV outbreaks in a research mouse colony.
- To identify potential sources and routes of LCMV introduction and spread within the facility.
- To evaluate the effectiveness of existing monitoring protocols and diagnostic methods.
Main Methods:
- Serological and virological assays were employed to detect LCMV infection in mice.
- Investigator interviews were conducted to gather information on animal handling and experimental procedures.
- Analysis of transplantable tumor lines and environmental factors was performed.
- Absorption of sera with LCMV antigen was used to confirm diagnostic specificity.
Main Results:
- Two LCMV epizootics occurred within two months, despite established monitoring policies.
- A transplantable tumor, initially free of LCMV, was implicated in virus spread.
- The precise origin of LCMV was undetermined, but introduction by wild or feral mice was hypothesized.
- No evidence of LCMV transmission from infected mice to human researchers was detected.
- A large animal facility was depopulated as a safety measure.
Conclusions:
- LCMV can spread rapidly within research facilities, even with monitoring.
- Transplantable tumors and wild rodents are potential sources of LCMV introduction.
- Accurate diagnostic methods, such as antigen-specific serum absorption, are vital for LCMV detection.
- Facility depopulation may be necessary to control LCMV outbreaks, highlighting the need for robust prevention strategies.