Pathogenesis of conjunctivitis caused by Newcastle disease viruses in specific-pathogen-free chickens

Figures & data

Table 1. Morbidity rates and lesion scores of conjunctivitis in chickens inoculated with NDV

							Histological conjunctivitis
							Mean lesion scores
							Lower palpebral conjunctiva		Upper palpebral conjunctiva
Experiment	Group^a	NDV strain	Virulence^b	Genotype	Inoculation route^c	Morbidity rate (%)	Right	Left	Right	Left
1	1	JP/Chiba/85	VV	VII	IM	100	1.1 (V, 0.7)^e	1.0 (V, 0.8)	0.6 (V, 0.5)	0.3 (V, 0.4)
	2	JP/Chiba/85	VV	VII	IN	100	1.7 (V, 2.3)	1.2 (V, 1.3)	0.5 (V, 0.8)	0.2 (V, 0.3)
	3	JP/Chiba/85	VV	VII	ED	100	2.4 (V, 2.6)	1.7 (V, 2.0)	1.0 (V, 1.2)	0.7 (V, 0.7)
	4	JP/TY-1/85	M	VI	IN	10	0.3 (V, 0.1)	0.0 (V, 0)	0.0 (V, 0)	0.0 (V, 0)
	5	JP/TY-1/85	M	VI	ED	0	0.1 (V, 0)	0.0 (V, 0)	0.0 (V, 0)	0.0 (V, 0)
2	6	JP/Ibaraki/85	VV	VI	ED	100	3.0(V, 2.8)	1.1(V, 0)	2.0 (V, 1.7)	0.7 (V, 0.1)
	7	JP/Okinawa/91	VV	VIII	ED	100	2.5 (V, 2.1)	1.5 (V, 0)	1.4 (V, 1.6)	0.5 (V, 0)
	8	Mukteswar	M	IV	ED	100	2.0 (V, 0)	0.2 (V, 0)	1.1 (V, 0)	0.1 (V, 0)
	9	B1	L	II	ED	100	1.2 (V, 0)	0.1 (V, 0)	0.8 (V, 0)	0.0 (V, 0)
	10	Control	–	–	–	0	0.0 (V, 0)	0.0 (V, 0)	0.0 (V, 0)	0.0(V, 0)
^a Number of birds each group was 10.
^b VV, viscerotropic velogenic; M, mesogenic; L, lentogenic.
^c IM, intramuscularly; IN, intranasally; ED, via eye drop.
^d Lesion scores: 0=no lesons, 1=mild, 2=moderate, 3=severe lesions.
^e Mean lesion score of conjunctivitis (mean lesions score of vascular necrosis); V, vascular necrosis.

Figure 1. Conjunctival congestion and haemorrhages (arrows) in a chicken inoculated intramuscularly with the JP/Chiba/85 of VVNDV. The chicken died 3 days after inoculation.

Figure 2. Mild lesions in the conjunctiva (arrows) of a chicken inoculated intramuscularly with JP/Chiba/85 of VVNDV. The chicken died 3 days after inoculation. Cellular infiltration and hyperplasia of the conjunctival epithelial cells in the base area of conjunctiva. The palpebra (P), third palpebra (nictitating membrane) (N), and scleral ossicle (S) are seen. Haematoxylin and eosin. Bar=800 μm.

Figure 3. Fibrinous vascular necrosis (arrows) in moderate lesions of the conjunctiva of a chicken inoculated via eye drop with JP/Chiba/85 of VVNDV. There are also hyperplasia and desquamation of conjunctival epithelial cells, oedema, and heterophilic infiltration in the lamina propria. The chicken died 3 days after inoculation. Haematoxylin and eosin. Bar=200 μm.

Figure 4. Fibrin thrombi (arrows) in the blood capillaries in moderate lesions of conjunctiva of a chicken inoculated via eye drop with JP/Chiba/85 of VVNDV. Desquamation of conjunctival epithelial cells and heterophilic infiltration in the lamina propria are seen. The chicken died 3 days after inoculation. Haematoxylin and eosin. Bar=200 μm.

Figure 5. Severe lesions in the conjunctiva of a chicken inoculated intranasally with JP/Chiba/85 of VVNDV. The chicken died 3 days after inoculation. Marked congestion, haemorrhage, cellular infiltration, oedema and vascular necrosis are seen diffusely throughout the palpebra. The palpebra shows marked swelling. Haematoxylin and eosin. Bar=800 μm.

Figure 6. Infraorbital sinus of a chicken inoculated intranasally with JP/Chiba/85 of VVNDV. Diffuse infiltration of heterophils, vascular necrosis (arrow), and oedema are seen in the lamina propria. Exudats includes fibrin and heterophils, is present in the sinus lumen. The chicken died 3 days after inoculation. Haematoxylin and eosin. Bar=200 μm.

Figure 7. Nasal turbinate of a chicken inoculated intranasally with JP/Chiba/85 of VVNDV. The chicken died 3 days after inoculation. There is vascular necrosis (arrow), oedema, and heterophilic infiltration in the lamina propria. Haematoxylin and eosin. Bar=100 μm.