Table 1 Histological criteria for assessing sections from duodenum, jejunum and aboral colon of mink kits

Degree of vacuolization of the enterocytes

Loss of staining of the cytoplasm in a group of enterocytes seen together with elongation and hypertrophy due to micro-vacuolization

Absent (0)

Mild: present focally (1)

Severe: present multifocal or disseminated (2)

Coccoid bacteria and rod-shaped bacteria (duodenum and jejunum)

Attached to enterocytes on the villi

Absent (−)

Present (+)

Semi-quantified degree of infiltration of neutrophils (duodenum and jejunum)

Neutrophils in villi

≤ 5 neutrophils/villi (0)

Several villi contained 5–10 neutrophils (1)

Several villi contained > 10 neutrophils (2)

Infiltrations of mononuclear cells

Distinguished from Peyer’s patches as diffuse, disorderly infiltrations of mononuclear cells in the lamina propria

Absent (−)

Present (+)

Intra-cytoplasmic eosinophil bodies of the enterocytes

Circular elements often located adjacent to the nuclei [15, 16]

Absent (−)

Present (+)

Atrophy and fusion of the villi (duodenum and jejunum)

Reduction of the height of villi and the spaces between them [15]

Absent (−)

Present (+)

Amount of enterocytic proliferation (duodenum and jejunum)

Number of mitosis in enterocytes

Number

Atrophy of mucosal lining (colon)

Reduction of mucosal height and normal architecture

Absent (−)

Present (+)