The progression of heartworm associated respiratory disease (HARD) in SPF cats 18 months after Dirofilaria immitis infection

Table 4 Histopathologic grading (Scores 0–3) of fixed perfused lung of cats on Day 510 post infection after L3 D. immitis infection

Site	Group^a	Mean Score	Standard Deviation	Significance^b
Bronchus	A	1.18	0.85
	B	0.97	0.80
	C	2.29	0.90	0.001
Bronchiole	A	0.44	0.54
	B	0.50	0.54
	C	1.40	0.93	0.001
Alveolus/smooth muscle	A	0.54	0.61
	B	0.26	0.48
	C	1.73	1.09	0.001
Arteriole	A	0.80	0.83
	B	0.80	0.88
	C	2.18	0.96	0.001
Pulmonary artery	A	0.50	0.54
	B	0.73	0.81
	C	2.34	0.84	0.001

^aGroup A (10): selamectin treatment initiated on Day 28 PI; Group B: (10) oral ivermectin treatment initiated Day 70 PI; Group C: infected untreated
^bGroup C (9) was significantly different than Groups A and Group B, which were not significantly different from each other