SESC case archive

05/05/2021 | Heart (porcine)

An (atypical) case of PDNS that set off the alarms

Samples were submitted of a 6-month-old hybrid male pig carcass with widespread petechial haemorrhagic lesions of lymph nodes, skin, kidneys, spleen, and other viscera, as well as gallbladder oedema. No signs of disease were observed in any of the pigs during the ante-mortem inspection. The veterinary service believed this to be a septicaemic process, but they wanted to rule out ASF/CSF because the lesions were compatible with these diseases. The possibility was unlikely since only one animal was affected in a batch of 48 animals.

After recovering from the inicial fright when looking at the images and the samples, the laboratory of virology at IRTA-CReSA performed the PCR and RT-PCR to detect ASF and CSF, respectively, on a weekend, with a a negative result. Once calmed down, histopathology was performed to clarify the nature of the lesions. We sent samples of lymph nodes, stomach, kidney, spleen, and tonsil to the pathology diagnostic lab.

The lesions observed microscopically are typically those of a generalized haemorrhagic diathesis, with the presence of variable amounts of blood in the medullary sinuses of all evaluated lymph nodes and haemorrhages of variable extent in the gastric submucosa. In addition, the kidney showed fibrinous exudative glomerulonephritis as well as interstitial haemorrhages of limited extension. This kidney lesion is morphologically classified as porcine dermatitis and nephropathy syndrome (PDNS). But in this case, the skin lesions are haemorrhagic, not necrotizing lesions as seen in typical PDNS cases.

In this case, since only one animal was affected, it would have been rare that ASF/CFS was involved. Even so, the images of the lesions may be so similar that laboratory analyses are essential to establish a definitive diagnosis. In the current epidemiological context, we further encourage veterinarians to refer any ASF/CSF suspicion to the SESC as soon as possible to rule out such infections. Early detection is one of the key pieces to control teh disease in case of an eventual entry in the country. The preferred samples for viral detection are lymph nodes, spleen, tonsil or blood, but we recommend that any altered viscera are sent in order to facilitate the task of reaching a definitive diagnosis. (AC)

Canal a escorxador amb presencia de petèquies cutànies generalitzades.

Pig carcass showing cutaneous generalized petechiae.

Limfonode gastrohepàtic envermellit. A la secció (insert) es pot observar que la lesió es localitza a la perifèria, indicatiu de reabsorció de sang extravasada als teixits que drenen cap a aquest limfonode. També es poden observar hemorràgies a la serosa del tracte digestiu.

Gastrohepatic lymph node showing dark purple colour. The cut surface revealed peripheral distribution, indicating blood resorption from the tissues that drain to this lymph node. Also the serosa surface of the viscera showed haemorrhages.

Esplenomegàlia, augment de mida de la melsa.

Splenomegaly, spleen increased in size.

Petèquies generalitzades a l’escorça d’ambdós ronyons.

Generalized  bilateral renal cortex petechiae.


Petèquies i equimosis a la superfície epicàrdica.

Epicardial petechiae and ecchymoses.

Petèquies a la mucosa de la bufeta de la orina.

The mucosa of the urinary bladder also shows generalized petechiae.

Limfonode que presenta una gran quantitat d’eritròcits lliures als sinus medul·lars, que indiquen que es tracta de reabsorció de sang extravasada en els teixits que drenen.

Lymph node showing abundant free erythrocytes within medullary sinuses, indicating blood resorption from the tissues that drain to this lymph node.

Les petèquies observades a l’escorça renal es corresponen amb hemorràgies intersticials corticals d’extensió variable.

The petechiae observed in the renal cortex are interstitial haemorrhages of variable extension.

Vasculitis necrotitzant en un dels vasos renals, lesió característica del SDNP.

Necrotizing vasculitis in one of the renal vessels, characteristic lesion of PDNS.

Glomerulonefritis exsudativa fibrinosa. Detall d’un glomèrul en el que s’observa fibrina i eritròcits lliures a la càpsula de Bowmann (punta de fletxa) així com necrosis segmental i presència de PMNN en els capil·lars glomerulars (fletxa).

Exudative fibrinous glomerulonephritis. Detail of a glomerulus showing fibrin and free erythrocytes within Bowmann’s capsule (arrowhead), as well as segmental necrosis and presence of PMNN in glomerular tufts.

El grup d’epidemiologia de l’IRTA-CReSA ha desenvolupat un software, per encàrrec del DARP, que permet, de forma immediata, generar un mapa de la distribució de les explotacions porcines a Catalunya amb les zones de protecció i vigilància al voltant de l'explotació afectada. Ambdues zones contenen un total 55 explotacions porcines, que s'haurien de visitar, i una capacitat total de 73.399 animals, que quedarien immobilitzats fins que es duguin a terme les visites. L'explotació afectada té una capacitat total de 3.150 animals els quals s'haurien de sacrificar."

The IRTA-CReSA epidemiology group has developed a software, commissioned by the DARP, which allows, immediately, to generate a map of the distribution of pig farms in Catalonia with protection and surveillance zones around the affected farm (red circles). In this simulation, both areas contain a total of 55 pig farms, which should be visited and tested, and a total capacity of 73,399 animals, which would be immobilized until the visits were carried out. The affected farm has a total capacity of 3,150 animals which would be slaughtered.


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