Last Friday, July the 6th we organized a practical workshop on lesion identification and description for porcine slaughterhouse official meat inspectors. To do this, we went to two pig slaughterhouses in Osona to collect condemned viscera. We would like to thank the collaboration and availability of the abattoir staff to facilitate the viscera collection.

In this post we discuss 10 of the most common lesions that we could observe in the viscera condemned during that day.

Two pathologists, SESC collaborators experts in swine pathology, Dr. Quim Segalés and Dr. Mariano Domingo gave a practical session on the description and identification of lesions in the Necropsy Room  of the Faculty of Veterinary Medicine of the UAB. The course included 21 participants who reviewed the course very positively.

 

Case 1

Swine lungs, 6 months, hybrid breed. Abscessing pneumonia, fibrous pleuritis, blood aspiration and lymphadenopathy (increase in size and redness of the lymph nodes) are observed.

A: Lymphoid hyperplasia and resorption of aspirated blood. B: Abscess with a fibrous capsule and degenerate neutrophil polymorphonuclear leukocytes inside it. C: Detail of the neutrophilic exudate.

 

Case 2

Swine liver, 6 months, hybrid breed. Image compatible with parasitic multifocal interstitial hepatitis (Ascaris suum). This lesion is also known as livers with “milky spots”.

A: Perilobular fibrosis and presence of hmorrhage. B: Detail of the interstitium where an exudate rich in macrophages (granulomatous) and abundant eosinophilic polymorphonuclear leukocytes is observed, which is associated with the presence of parasites.

 

Case 3

Swine lung, 6 months, hybrid breed. Aspiration of blood: during the sacrifice blood enters the airways. It should not be confused with a haemorrhagic lesion or aspiration pneumonia, the latter consists in aspiration of digestive content that generates an inflammatory and necrotic reaction on the pulmonary parenchyma that in this case we do not see.

A: Presence of blood (red) already reabsorbed to the subpleural lymphatic plexus. B: Presence of blood inside the pulmonary alveoli and bronchioles.

 

Case 4

Swine kidneys, 6 months, hybrid breed. Presence of multiple renal cysts. It is a congenital alteration without pathological significance.

 

Case 5

Swine lung, 6 months, hybrid breed. Darkening of a portion of the diaphragmatic lobe, also with blood aspiration. This image resembles the images of lung consolidation observed when there is a pneumonia but in this case it is atelectasis (collapse of the pulmonary alveoli, the lack of air within the alveoli causes the darker colour than in the rest of the viscera).

A: Atelectasis of the superficial portion of the lung. B: The walls of the alveoli come into contact with each other due to the lack of air within, but there is no presence of an inflammatory infiltrate.

 

Case 6

Swine lung, 6 months, hybrid breed. Another example of atelectasis. It does not consist of any pathological lesion. We do not know the origin of this artifact but it could be mechanical compression of the alveoli during the extraction of the viscera of the thoracic cavity.

 

Case 7

Pig’s hearts, 6 months, hybrid breed. This image corresponds to fibrous pericarditis (chronic), the heart of the right is normal, to compare. This lesion is the evolution of a fibrinous pericarditis (fibrin usually looks like a French omelette, and being a more acute lesion the animal would present clinical signs, such as fever) caused by a bacterial infection, for example, by Glässer’s disease (Haemophilus parauis).

Different degrees of thckening (fibrosis) of the epicardium (A and B) compared to a normal epicardium (C).

 

Case 8

Swine lung, 6 months, hybrid breed. Fibrous pleuritis (chronic). As in the case of pericarditis,  it is the chronification of a fibrinous pleuritis caused by a bacterial infection.

Increase in thickness and fibrosis of the pleura with papillary projections.

 

Case 9

Swine lung, 6 months, hybrid breed. Focal lesion of necrotic-hemorrhagic pleuropneumonia, it is a very typical lesion of Actinobacillus pleuropneumoniae.

 

Case 10

Swine spleens, 6 months, hybrid race. Splenomegaly (increase in spleen size) with hemorrhage and necrosis of the splenic parenchyma. The one below shows adherences to the mesenterium. It is a very common injury due most likely to a torsion of the organ with the consequent ischemia and passive congestion. This cases are often associated with jaundice in teh carcass.