**6. Histopathological lesions**

Lungs, the primarily affected organ, microscopically shows a variety of lesions from congestion of capillaries with thickened interlobular septa and atelectasis to severe lesions of perivascular and bronchial infiltration of inflammatory cells. There may be

*Pests, Weeds and Diseases in Agricultural Crop and Animal Husbandry Production*

*multocida* directly from clinical swab specimens should be feasible.

**5. Gross pathological lesions**

swine pasteurellosis.

assays except for a negative reaction in one of the 19 isolates that the other assays identified as toxigenic. They suggested that PCR detection of toxigenic *Pasteurella* 

On post-mortem examination of dead pigs from natural outbreaks, the gross pathological lesions may be marked by congestion and petechial haemorrhages on all over the serous membranes. Widespread petechial haemorrhages in the wall of thoracic cavity is the hallmark of the disease. Hydrothorax with presence of strawcoloured fluid in thoracic cavity can be seen (**Figure 1**). All the visceral organs may exhibit petechial to ecchymotic haemorrhages on the serosal surfaces. In some animals, hydrothorax, pleurisy and hydropericardium can also be prominent [18, 19]. The lungs usually show congestions with varying degrees of consolidation and with a marked thickening of the interlobular septa, pleura and rubbery consistency of lungs. There may be petechiae over the lungs (**Figure 2**). In acute cases the lungs may be severely consolidated with liver-like consistency. Whereas, subacute to chronic infection manifest grossly by marbled appearance of lungs (**Figure 3**), rubbery consistency and thickening of pleura (**Figure 4**), and emphysematous changes in lungs [20–22]. Heart may be severely congested and there may be presence of petechial as well as haemorrhagic streaks and necrotic foci which can be visible upon removal of pericardium (**Figure 5**). Rounding of heart and haemorrhages were also observed by Kapoor *et al.* [23]. The liver is one of the severely affected organs in this disease. The lesions may be characterized by congestion, petechiae and multiple necrotic foci on the surface of liver [21, 22]. Splenomegaly is a constant lesion seen in all the cases. There may be haemorrhagic enteritis in pigs died of

*Consolidation of lungs, hydrothorax, congested liver and splenomegaly in a pig died of swine pasteurellosis.*

**238**

**Figure 1.**

**Figure 4.** *Rubbery consistency of lungs and pleural thickening in a pig died of swine pasteurellosis.*

**Figure 5.** *Severe congestion and presence of haemorrhagic streaks in heart of a pig.*

presence of oedema in lungs. The pneumonic lesions microscopically characterized by fibrinous pneumonia (**Figure 6**), necrotizing fibrinohaemorrhagic pneumonia, (**Figure 7**), interstitial pneumonia (**Figure 8**) and purulent bronchopneumonia (**Figure 9**). The acute fibrinous pneumonia characterized by serofibrinous exudation and infiltration with polymorphonuclear cells, macrophages and erythrocytes may

**241**

**Figure 7.**

**Figure 6.**

*Pathological Changes Associated with Natural Outbreak of Swine Pasteurellosis*

be observed. The bronchial and alveolar lumen usually filled with infiltrated erythrocytes, polymorphonuclear cells and macrophages (**Figure 10**). The alveoli showed variable changes from congestion to severe haemorrhages. Pleura and alveolar septa get thickened with fibrin, oedema and infiltration of polymorphonuclear cells. [23–26].

*Photomicrograph showing necrotizing fibrinohaemorrhagic pneumonia (H&E X400).*

*DOI: http://dx.doi.org/10.5772/intechopen.94849*

*Photomicrograph showing Fibrinous exudate in alveoli (H&EX400).*

*Pathological Changes Associated with Natural Outbreak of Swine Pasteurellosis DOI: http://dx.doi.org/10.5772/intechopen.94849*

#### **Figure 6.**

*Pests, Weeds and Diseases in Agricultural Crop and Animal Husbandry Production*

*Rubbery consistency of lungs and pleural thickening in a pig died of swine pasteurellosis.*

presence of oedema in lungs. The pneumonic lesions microscopically characterized by fibrinous pneumonia (**Figure 6**), necrotizing fibrinohaemorrhagic pneumonia, (**Figure 7**), interstitial pneumonia (**Figure 8**) and purulent bronchopneumonia (**Figure 9**). The acute fibrinous pneumonia characterized by serofibrinous exudation and infiltration with polymorphonuclear cells, macrophages and erythrocytes may

*Severe congestion and presence of haemorrhagic streaks in heart of a pig.*

**240**

**Figure 5.**

**Figure 4.**

*Photomicrograph showing Fibrinous exudate in alveoli (H&EX400).*

**Figure 7.** *Photomicrograph showing necrotizing fibrinohaemorrhagic pneumonia (H&E X400).*

be observed. The bronchial and alveolar lumen usually filled with infiltrated erythrocytes, polymorphonuclear cells and macrophages (**Figure 10**). The alveoli showed variable changes from congestion to severe haemorrhages. Pleura and alveolar septa get thickened with fibrin, oedema and infiltration of polymorphonuclear cells. [23–26].

**Figure 8.** *Photomicrograph showing interstitial pneumonia (H&E X400).*

**Figure 9.** *Photomicrograph showing flooding of polymorphonuclear cells in alveoli (H&E X400).*

Haemorrhages and necrosis may be evident in heart. Sub-pericardial haemorrhage and presence of erythrocytes in between the myocardial fibers may be remarkably noted. Myocardial necrosis can be marked as loss of striations of muscle fibers (**Figure 11**). There may be presence of thrombi in the blood vessels and fibrinous pericarditis in heart as a common finding. Liver is the consistently

**243**

**Figure 11.**

**Figure 10.**

*Pathological Changes Associated with Natural Outbreak of Swine Pasteurellosis*

affected organ in this disease and the lesions reveal as invariably dilated and engorged blood vasculature and sinusoids. Focal areas of haemorrhages are usually seen. There will be hepatocytic swelling and increased activity of Kupffer cells in the parenchyma and focal areas of degenerative changes and hepatocytic necrosis.

*Photomicrograph showing necrosis of myocardium and haemorrhages (H&E X400).*

*Photomicrograph showing bronchiolar lumen containing exudate composed of erythrocytes (H&E X400).*

*DOI: http://dx.doi.org/10.5772/intechopen.94849*

*Pathological Changes Associated with Natural Outbreak of Swine Pasteurellosis DOI: http://dx.doi.org/10.5772/intechopen.94849*

#### **Figure 10.**

*Pests, Weeds and Diseases in Agricultural Crop and Animal Husbandry Production*

Haemorrhages and necrosis may be evident in heart. Sub-pericardial haemor-

rhage and presence of erythrocytes in between the myocardial fibers may be remarkably noted. Myocardial necrosis can be marked as loss of striations of muscle fibers (**Figure 11**). There may be presence of thrombi in the blood vessels and fibrinous pericarditis in heart as a common finding. Liver is the consistently

*Photomicrograph showing flooding of polymorphonuclear cells in alveoli (H&E X400).*

**242**

**Figure 9.**

**Figure 8.**

*Photomicrograph showing interstitial pneumonia (H&E X400).*

*Photomicrograph showing bronchiolar lumen containing exudate composed of erythrocytes (H&E X400).*

**Figure 11.** *Photomicrograph showing necrosis of myocardium and haemorrhages (H&E X400).*

affected organ in this disease and the lesions reveal as invariably dilated and engorged blood vasculature and sinusoids. Focal areas of haemorrhages are usually seen. There will be hepatocytic swelling and increased activity of Kupffer cells in the parenchyma and focal areas of degenerative changes and hepatocytic necrosis.

#### **Figure 12.**

*Photomicrograph of kidney showing haemorrhages and sloughing of lining epithelium of renal tubules (H&E X400).*

The hydropic degeneration of hepatocytes are characterized by cytoplasmic vacuolations and areas of hepatocytic necrosis with cellular infiltration. There may be dilatation of sinuses and disruption of hepatic cords seen in affected animals [20, 22, 27]. Lesions in Kidneys reveal as vascular congestion and focal areas of haemorrhages. Haemorrhages used to be intertubular (**Figure 12**). Cortical tubular epithelium may invariably swollen or degenerated with increased cytoplasmic granularity. The degenerative and necrotic changes of tubular epithelium will be diffuse in nature. Generalized degenerative and necrotic changes in the tubular epithelial cells may also be seen with variable severity from mild to high [20, 28].

There will be depletion of lymphocytes from germinal centre of the spleen and widespread necrosis can also be seen Spleen reveals as variably dilated and engorged vasculature, haemosiderosis, necrosis of lymphoid elements and infiltration of inflammatory cells mainly neutrophils [29, 30]. The microscopic lesions in the intestine are characterized by haemorrhages, necrosis of villi epithelium and desquamation of lining epithelium with focal infiltration of mononuclear cells in lamina propria and increase number of goblet cells [25].

#### **7. Conclusions**

Swine Pasteurellosis is an acute infection in swine caused by members of the *Pasteurella multocida*. Swine throughout the world are affected by pasteurellosis. *Pasteurella multocida* of swine can be isolated from natural field cases. Field isolate of *Pasteurella multocida* on sheep blood agar yield non-hemolytic, round, grayish, smooth or mucoid colonies. The isolates are Gram negative, cocco-bacilli in morphology and non-motile facultative anaerobe. Biochemically the isolates are positive for oxidase, catalase, indole production, reduction of nitrate, glucose and sorbitol

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India

**Author details**

Mamta Choudhary1

**Acknowledgements**

carry out the research**.**

**Conflict of interest**

*Pathological Changes Associated with Natural Outbreak of Swine Pasteurellosis*

fermentation, but fail to ferment lactose, arabinose and adonitol. The isolate also found negative for citrate, lysine decarboxylase, urease, phenylalaline deamination and H2S production. The genomic DNA of test isolates and organisms upon PCR using the primer pair KMT1SP6 and KMT1T7 produce an amplified product of approximately 460 bp size. On post-mortem examination of dead pigs, the gross pathological lesions observed in different organs marked by congestion, petechial to ecchymotic haemorrhages on serosal surfaces of all the visceral organs. The histopathological examination reveals as acute fibrinous pneumonia with variable degree of haemorrheges; mild to severe congestion and focal haemorrhages in heart, with loss of striation of heart muscle, thrombus formation in cardiac blood vessels, hydropic degeneration in liver, haemorrhages, hepatocytic necrosis and increased activity of Kupffer cells in the hepatic parenchyma and mild to severe necrosis in

Authors are thankful to the Dean, Veterinary College, Anjora, Durg, Chhattisgarh and Indian council of Agricultural Research for providing the necessary facilities to

\*, Binod Kumar Choudhary1

\*Address all correspondence to: chiyamum@gmail.com

provided the original work is properly cited.

1 ICAR-National Institute of Biotic Stress Management, Raipur, Chhattisgarh, India

2 Department of Veterinary Pathology, Chhattisgarh Kamdhenu University, Durg,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

and Ratan Chandra Ghosh<sup>2</sup>

*DOI: http://dx.doi.org/10.5772/intechopen.94849*

renal tubules with presence of focal haemorrhages.

The authors declare no conflict of interest.

*Pathological Changes Associated with Natural Outbreak of Swine Pasteurellosis DOI: http://dx.doi.org/10.5772/intechopen.94849*

fermentation, but fail to ferment lactose, arabinose and adonitol. The isolate also found negative for citrate, lysine decarboxylase, urease, phenylalaline deamination and H2S production. The genomic DNA of test isolates and organisms upon PCR using the primer pair KMT1SP6 and KMT1T7 produce an amplified product of approximately 460 bp size. On post-mortem examination of dead pigs, the gross pathological lesions observed in different organs marked by congestion, petechial to ecchymotic haemorrhages on serosal surfaces of all the visceral organs. The histopathological examination reveals as acute fibrinous pneumonia with variable degree of haemorrheges; mild to severe congestion and focal haemorrhages in heart, with loss of striation of heart muscle, thrombus formation in cardiac blood vessels, hydropic degeneration in liver, haemorrhages, hepatocytic necrosis and increased activity of Kupffer cells in the hepatic parenchyma and mild to severe necrosis in renal tubules with presence of focal haemorrhages.
