Indices of Disease Severity in Diseases that Cause Abscesses in Target Organs

Some animal diseases cause variable numbers of abscesses of varying severity in target organs. In assessing the efficacy of vaccines developed to combat these diseases it is necessary to devise indices of disease severity that incorporate the number of abscesses in an animal and the severity scores of the abscesses. Three indices are defined and their relative merits are discussed. Some of the distributional properties of the indices are examined and their relevance to statistical analyses are discussed.