Monitoring Pathogen-Induced Sickness in Mice and Rats

Area of Science:

• Neuroscience
• Immunology
• Animal Behavior

Background:

• Sickness behavior monitoring is crucial for understanding neurochemical and physiological changes during pathogen-induced immune activation.
• Current methods suffer from inconsistent protocols and rater bias, complicating data interpretation.
• A standardized, unbiased approach is needed to accurately assess sickness progression.

Purpose of the Study:

• To present a novel, non-invasive, and unbiased protocol for assessing sickness behavior in experimental animals.
• To offer a straightforward method for quantifying sickness progression following pathogen exposure.
• To provide reliable physiological markers for sickness, including body temperature and weight changes.

Main Methods:

• A simple five-point scale was developed to assess the presence of four distinct sickness behaviors.
• The protocol involves scoring animals at various time points post-pathogen exposure.
• Body temperature and weight changes were recorded as additional physiological indicators.

Main Results:

• The protocol successfully assessed sickness behaviors in male and female rodents following intraperitoneal injection of lipopolysaccharide and polyinosinic:polycytidylic acid.
• The method proved effective across both pubertal and adult animal populations.
• The five-point scale effectively removed ambiguity and bias associated with subjective symptom severity ratings.

Conclusions:

• This protocol offers a reliable and unbiased method for monitoring sickness behavior in research settings.
• The standardized approach enhances the consistency and reconcilability of experimental results.
• The inclusion of physiological markers provides a comprehensive assessment of sickness.