THE MOUSE INFECTIVITY TITRATION OF INFLUENZA VIRUS

Area of Science:

• Virology
• Immunology
• Statistical Analysis

Background:

• Accurate quantification of viral infectivity is crucial for understanding disease pathogenesis and evaluating antiviral efficacy.
• Mouse infectivity titrations are a standard method for determining influenza virus potency.
• Establishing statistical significance in titration endpoints enhances the reliability of experimental results.

Purpose of the Study:

• To statistically validate endpoints used in mouse infectivity titrations of influenza virus.
• To determine the minimum significant differences between titration results based on various criteria.
• To provide a quantitative basis for interpreting influenza virus infectivity data.

Main Methods:

• Performed five replicate mouse infectivity titrations for influenza virus.
• Calculated 50% endpoints using three distinct criteria: pulmonary lesions, mortality, and a weighted composite score.
• Computed standard deviations and determined probability levels for significance between endpoints.

Main Results:

• Identified significant differences for lesion, death, and weighted composite endpoints.
• Determined that differences of 0.99, 0.77, and 0.73 logarithmic units, respectively, are statistically significant (19 out of 20 chances).
• The weighted composite endpoint demonstrated higher statistical sensitivity.

Conclusions:

• The study establishes clear statistical thresholds for significant findings in influenza virus mouse infectivity titrations.
• These validated endpoints improve the precision and reproducibility of viral infectivity assays.
• The findings support the use of a weighted composite endpoint for enhanced statistical power in influenza research.