Table 1. Histopathological scoring criteria (0–5) for guinea pig inoculation sites.

Score	Histopathological Description of Skin Biopsy Sites
0	No inflammatory changes present, tissue is within normal limits
1	1–3 distinct and small aggregates of macrophage dominated inflammation. Other cell types are rare. Inflammation is localized to the deep dermis without tissue infiltration.
2	More extensive macrophage dominated inflammation with coalescing foci or linear infiltrate in the deep dermis. Neutrophils are present. There is limited tissue infiltration and no tissue destruction or edema.
3	Macrophage dominated inflammation remains the principal component. Lymphocytic inflammation is present to more extensive degree. Neutrophils are not associated with tissue necrosis. Inflammatory infiltrate extends into the deep dermis and superficial subcutis and along tissue planes to both endos of the biopsy specimen. Edema is uncommon.
4	Inflammation is increasingly pyogranulomatous. Lymphocytes are less common and often peripheral to granulomatous inflammation. Edema is present and inflammation extends into the superficial dermis ad deep into the subcutis. Necrosis is absent.
5	Similar to a score of 4, the inflammation is widespread and pyogranulomatous; however, these most severely affected samples have one to multiple foci of liquefactive necrosis with or without collagen degeneration and a very high proportion of neutrophils.