Age-associated variability in susceptibility of Swiss Webster mice to MPV and other excluded murine pathogens

Area of Science:

• Veterinary Pathology
• Laboratory Animal Science
• Infectious Disease Surveillance

Background:

• Effective detection of murine pathogens in research colonies relies on agent transmissibility and sentinel mouse sensitivity.
• Sentinel susceptibility is influenced by agent properties and host factors like mouse age, strain, and sex.

Purpose of the Study:

• To evaluate the impact of sentinel mouse age on the detection efficiency of infectious agents.
• To determine if more frequent sentinel replacement is needed to enhance infectious agent detection in murine colonies.

Main Methods:

• Compared 4-wk-old, 12-wk-old, and aged Swiss Webster female sentinel mice in a standardized health surveillance program.
• Used experimentally infected mice (mouse parvovirus) and naturally infected mice (9 agents) to assess transmission to sentinels.
• Evaluated transmission via contact and soiled-bedding routes across different sentinel ages.

Main Results:

• For agents transmitted via soiled bedding (MPV, MHV, MNV, TMEV, pinworms), sentinel age did not affect transmission rates.
• No significant difference in susceptibility was observed across sentinel ages for the tested infectious agents.
• The study utilized both experimental inoculation and natural infection models for comprehensive evaluation.

Conclusions:

• Sentinel mouse age, particularly for mice over 12 weeks old, does not significantly alter susceptibility to several common infectious agents.
• Current health surveillance protocols using mice older than 12 weeks are effective without needing more frequent sentinel replacement based on age.
• Findings support the continued use of aged sentinel mice in health surveillance programs, optimizing resource allocation.