Table 1.

Scoring and severity of scoring criteria for ultrastructural changes following in-vitro inoculation by whole cell and LPS endotoxin of P. multocida B:2

Normal Score 0	Early events (Mild) Score 1	Intermediate events (Moderate) Score 2	Late events (Severe) Score 3
Normal organelles	Mitochondrial swelling	Mitochondrial cristolysis	Mitochondrial vacuoles
	Cytocavity network dilation	Cytocavity network membrane fragmentation	Cytoplasmic vesiculation
	Nuclear envelope dilatation	Nuclear envelope collapse and invagination	Nuclear envelope disintegration
	Eccentric nucleoli	Nucleoplasm rarefaction	Nuclear chromatin peripheralisation