Pathology of spontaneous and experimental infections by Goose haemorrhagic polyomavirus

Figures & data

Figure 1. Gross and microscopic lesions in a 8-week-old gosling, after fatal evolution of spontaneous HNEG. (A) Macroscopic appearance of the kidney, showing severe swelling and hemorrhages. (B) Macroscopic view of urate deposits within the tibio-tarsometatarsal joint. (C) Photomicrograph of a normal cloacal bursa. Haematoxylin & Eosin.×100 (Bar 100 μm). (D) Photomicrograph of the cloacal bursa: multifocal, marked centrofollicular lympholysis without inflammatory cells. Haematoxylin & Eosin.×400. (Bar 25 μm). (E) Photomicrograph of kidney tissue section, showing severe, multifocal necrosis of tubules (arrows). Haematoxylin & Eosin.×400. (Bar 25 μm).

Figure 2. Microscopic lesions observed day-8 post-inoculation. Experimental reproduction of HNEG in goslings. (A) At the clinical stage of the disease (dpi 8), moderate lymphocyte depletion was observed in cloacal bursa (A, Bar 100 μm) while there was extensive tubular necrosis (B, Bar 250 μm). (C) A discrete nuclear enlargement of endothelial cell involved various organs as soon as dpi3; (kidney, (C), Bar 50 μm). (D) Later in the course of the disease, multifocal marked arteriolitis, with vessel wall infiltration and major endothelial cell activation, (D) was observed in most tissues (C, Bar 15 μm). Haematoxylin & Eosin.

Table 2. Histological findings during the course of experimental infection of goslings^a

Tissues	Day 2		Day 3		Day 4		Day 5		Day 8
	Birds	Lesion intensity	Birds	Lesion intensity	Birds	Lesion intensity	Birds	Lesion intensity	Birds	Lesion intensity
Spleen
Follicular depletion	–		2/4 (a-b)	0/+	4/4	++/+++	4/4	+++	4/4	+++
Arteriolitis	–		–				4/4	+	3/4(a-c-d)	++/+++
Kidney
Epithelial nephritis	–		–		–		1/4 (d)	+	4/4	+++
Arteriolitis	–		–		–		1/4 (a)	+	4/4^b	++
Eye
Arteriolitis	–		–		–		2/4 (a-b)	+/++	4/4	+++
Pancreas
Nuclear swelling, endothelial cells	–		–		–		–		4	++
Arteriolitis	–		–		–		–		4/4	+/++
Lung
Nuclear swelling, endothelial cells	–		2/4 (a-d)	+	4/4	+	4/4	+/++	4/4	+++
Arterilolitis	–		1/4 (d)	0/+	1/4 (d)	+	3/4 (a-b-d)	+	4/4	++
Heart
Nuclear swelling, endothelial cells	–		1/4 (d)	+	2/4 (b-d)	+	4/4	+/++	4/4	++/+++
Arteriolitis	–		1/4 (d)	0/+	–		3/4 (a-b-d)	+	3/4 (a-c-d)	++
Cloacal bursa
Follicular lympholysis	–		–		3/4 (b-c-d)	+	4/4	++	4/4	+++
Heterophilic infiltrate	–		–		1/4 (d)	0/+	2/4 (b-c)	+/++	4/4	+/++
Small intestine
Nuclear swelling, endothelial cells	–		3/4 (a-b-d)	+	4/4	+	4/4	+/++	4/4	+++
Arteriolitis	–		1/4 (d)	0/+	1/4 (d)	+	3/4 (a-b-d)	+	4/4	+/++
Caeca
Nuclear swelling, endothelial cells			3/4 (a-b-d)	+	4/4	+	4/4	+/++	4/4	+++
Arteriolitis			3/4 (a-b-d)	0/+	1/4 (d)	+	3/4 (a-b-d)	+	4/4	+/++
^a Day 8 corresponds to the death or sacrifice of diseased birds. For each day post-inoculation, 4 birds (noted a, b, c, d) and 2 mock-infected birds were analyzed. Lesion severity was graded from 0 to+++:+ minimal;++ mild;+++ severe.
^b Microthrombosis (kidney).

Table 1. Detection of GHPV by PCR during the course of an experimental infection of goslings^a

Tissues	Day 2	Day 3	Day 4	Day 5	Day 8
Liver	0/4	3/4 (a,b,c)	4/4	4/4	4/4
Spleen	0/4	3/4 (a,b,d)	4/4	4/4	4/4
Kidney	0/4	3/4 (a,b,d)	4/4	4/4	4/4
Cerebral cortex	0/4	1/4 (a)	2/4 (a,b)	3/4 (b,c,d)	4/4
Pancreas	0/4	2/4 (b,d)	4/4	3/4 (a,c,d)	4/4
Lung	0/4	2/4 (b,d)	4/4	4/4	4/4
Cloacal bursa	0/4	3/4 (a,b,d)	4/4	3/4 (a,c,d)	4/4
Thymus	1/4 (b)	3/4 (a,b,d)	4/4	4/4	4/4
Cloacal swab	0/4	0/4	0/4	0/4	4/4
Plasma	0/4	0/4	0/4	0/4	4/4
^a Detection of GHPV DNA from tissues of goslings inoculated with 10^8 genome-equivalent GHPV. Day 8 corresponded to the death or sacrifice of diseased birds. For each day post-inoculation, 4 birds (a, b, c, d) and 2 mock-infected birds were analyzed. Control birds remained PCR negative throughout the experiment.

Figure 3. Electron microscopy on tissues of goslings day 8 post-inoculation. (In all pictures, bar=500 nm). (A) Crystalline organization of virions in the nucleus of an endothelial cell adjacent to a feather follicle. (B) Endothelial cell in the pulp of a feather follicle. Note the virions, margination of chromatin and organization of organelles around the nucleus. The cytoplasm of GHPV-infected cells contain no recognizable mitochondria. (C) Capillary epithelial cell of the lung. Virions are released from the nucleus to the cytoplasm of the cell (top of the picture). (D) Proximal convoluted tubular epithelial cell in the kidney. Margination of chromatin. Note the mitochondrial vacuolation.