Table II.

Histological observations of lesions from rabbits infected with wild-type or mutant viruses. All animals were subjected to a complete post-mortem examination. Tissue materials were from the injection site (ear [primary site]) and parotid lymph node (secondary site).

	Lesion intensitya with the indicated virus
Clinical signs	Day 5 p.i.				Day 8 p.i.				Day 13 p.i.
	Wild-type	MYXV-ΔM148R	MYXV-ΔM149R	MYXV-ΔM148R ΔM149R	Wild-type	MYXV-ΔM148R	MYXV-ΔM149R	MYXV-ΔM148R ΔM149R	Wild-type	MYXV-ΔM148R	MYXV-ΔM149R	MYXV-ΔM148R ΔM149R
Primary siteb: Perivascular dermatitis
Epidermal spongiosis and vesicles	–	–	–	–	++++	+	+++	+	+	+	+	–
Edema	+++	+++	+++/++++	++/+++	++++	+++	++	++	+++	++	+++	++
Focal interstitial microhaemorrages	–	+	++	–	++	+	++	+	++	–	+++	–
Focal thrombosis	+	+	–	+	++	+	++	+	–	–	++	+
Heterophils	++/+++	++/+++	++/+++	++/+++	++++	++	+++	++	+++	+	++	+
Mononuclear cells	+	+	+	+	++	++++	++	++++	+++	++++	+++	++++
Activated fibroblasts	++	++	++	++	+++	+++	+++	+++	+++++	+++	+++	+++
Interstitial mucinosis	+++	+++	+++	++	+++	++	+++	+++	++++	++	+++	++
Secondary sitesc: Lymphadenitis
Lymphodepletion	–	–	–	–	–	–	–	–		–	–	–
Lymphoid hyperplasia	++/+++	++	++	++	+++	+++	+++	++		++	++	++
Focal histiocytosis	++++	+++	+++/++++	++/+++	+++	+++	+++	+++		++	+++	+/–
Infiltration by heterophils	+++	+++	+++	++	+++	++	+++	+		–	+	–
Activated fibroblasts	–	–	–	–	+++	++	++	+		–	+	–
Interstitial mucinosis	–	–	–	–	+++	+	+	+		–	–	–

^aLesion intensity: +, minimal; ++, mild; +++, moderate; ++++, marked or +++++, severe.

^bSamples were taken from lesions at the inoculation site (ear).

^cSamples were taken from parotid lymph nodes. Main cells of inflammatory response are highlighted.