Swine pasteurellosis is usually observed in descript as well as nondescript pigs imparting in huge economic losses to the pig producers. The disease is characterized by pyrexia, dullness, staggering gait, anorexia, serous nasal discharge and dyspnoea. Case fatality rate may as high as 95% in adult animals and 100% in piglets. Typical lesions of oedematous swellings may remarkably visible in the pharyngeal region, these swellings spread to the ventral cervical region and brisket of pigs. Gross lesions include severe pneumonia and haemorrhages in lungs, petechial haemorrhages on serous membranes and other visceral organs. Lymph nodes usually get enlarged, oedematous and haemorrhagic. The blood smears from heart blood and tissue impression smears reveal teaming numbers of bipolar organisms indicating the presence of Pasteurella spp., the etiological organism. The bacteriological isolation and characterization of causative agent should be ruled out to identify by Gram’ staining for purity and bipolar morphology and biochemical characterization of the organisms. Molecular characterization necessitates to confirm Pasteurella multocida along with capsular types of the organism. Histopathological examination of lungs usually reveals typical fibrinous bronchopneumonia, multifocal suppuration and pleural thickening. Heart of some pigs may show presence of thrombi, haemorrhages and necrosed myocardium.
- Swine Pasteurellosis
- Pasteurella multocida
- Haemorrhagic septicaemia
- capsular types
- fibrinous bronchopneumonia
Capsular types A and D cause economic losses in swine because of their association with progressive atrophic rhinitis and enzootic pneumonia . Its association with acute septicemic pasteurellosis in pigs has been recognized.
Yet, Pasteurellae have been shown to be a common microflora of the upper respiratory tract in normal animals . The organisms more often than not act as secondary invaders in animals with concurrent diseases or suffering from debilitating stressful conditions. HS is a peracute disease and is considered to be one of the most economically important diseases in Asia particularly in South and South East Asia leading to huge economic loss in livestock industry.
The scope of epidemiology in modern animal husbandry practice is continuously widening. Epidemiological data provide information on various diseases which are pre-requisite for planning, execution and monitoring of disease control programmes. It is an important requirement for assessing economic impact of a disease and also for developing disease forecasting system. The disease is usually associated with wet, humid weather and increased incidence is recorded during wet, humid weather and during wet seasons. In countries where systemic epidemiological studies have been carried out, it has become evident that outbreaks do occur throughout the year but those occurring during wet seasons tend to spread presumably due to the longer survival of the organism under moist conditions . Zhao
3. Cultural, Phenotypic and Biochemical Characterization
4. Genotypic Chracterization of
Since the initial development of the PCR in 1985, the basic principle of
5. Gross pathological lesions
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 straw-coloured 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, 21, 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
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 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 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, 24, 25, 26].
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 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. 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 .
Swine Pasteurellosis is an acute infection in swine caused by members of the
Authors are thankful to the Dean, Veterinary College, Anjora, Durg, Chhattisgarh and Indian council of Agricultural Research for providing the necessary facilities to carry out the research
Conflict of interest
The authors declare no conflict of interest.
Collins, F M. Mechanisms of acquired resistance to Pasteurella multocida infection: a review. Cornell Vet. J.1977: 67: 103-138
Soltys, M A. Pasteurella, Francisella and Actinobacillus. In: Introduction to Veterinary Microbiology. 1979.National Government Publication, Universiti Pertanian Malaysia, Ipoh, Malaysia, 158- 167
Biberstein, EL. Handbook Series in Zonooses. (Stoenner, H., Torten, M. and Kaplan, W. eds.), CRC Press Inc., Boca Raton, Florida, pp 495-514 (1079)
Rhoades, K R and Rimler, R B. Capsular groups of Pasteurella multocidaisolated from avian hosts. Avian Dis.1987: 31: 895-898
Boyce JD, Adler B. A capsular Pasteurella multocidaB: 2 can stimulate protective immunity against pasteurellosis. Infect. Immun. 2001; 69:1943-1946
Carter, GR and De Alwis, MCL. Haemorrhagic septicemia, 1989. pp.131-160.In (Eds) C. Adlam and J.M. Rutier Pasteurella and Pasteurellosis. Academic Press Ltd. London, England
Djordjenic SP, Eamens GJ, Ha HW, MJ and Chin, JC. Demonstration of Australian Pasteurella multocidaisolates from sporadic outbreaks of porcine pneumoniaare non toxigenic (toxA) and display heterogeneous DNA restricrion enzyme profiles compared with toxigenic isolates from herds with progressive atrophic rhinitis. J. Med. Microbiol. 1998; 47(8):679-688
De Alwis, MCL. Haemorrhagic septicaemia. ACIAR Monograph 1990. No.57,p.36
Campbell, RSF. Pasteurellosis. In: Veterinary Epidemiology. Melbourne, Australian Universities’ International Development Program, 1983. 113-115
Boyce, JD, M Harper, IW Wilkie and Adler, B. Pasteurella. In: Pathogenesis of Bacterial Infections in Animals (Gyles, C.L., Prescott, J.F., Songer, G. and Thoen, C.O. eds.)., Wiley-Blackwell, Ames, 2010. p 664-664.
Hawari, AD, Obeidat, M, Awaisheh, SS, AlDaghistani HI and Al-Abbadi, AA. Am. J. Anim. Vet. Sci., 2014:9: 116-121
Zhao, G, Pijoan, C, Murtaugh, M P Molitor, T W Use of restriction endonuclease analysis and ribotyping to study epidemiology of Pasteurella multocidain closed swine herds. Infect Immun. 1992: 60:1401-1405.
Bergey, DH, Harrison, FC, Breed, RS, Hammer, BW and Huntoon, FM. Bergey’s Manual of determinative bacteriology 9th edn., 1994. Williams and Wilkins, Baltimore
Chawak, MM, Verma, KC, Kataria, JM and Kamar, AA. Characterization of indigenous isolates of avian P. multocida.Indian Comp. Microbiol. Immunol. Infec. Dis. 2000: 21:111-114
Anupama, M, Venkatesha, MD, Yasmeen, N and Gowda, RNS. Evaluation of polymerase chain reaction (PCR) for identification of virulent P. multocidaand its comparison with animal inoculation test. Indian J. Anim. Sci. 2003: 73:166-167
Rapley R, Theophilus BOM, Bevan IS, Walkar MR. Fundamentals of polymerase chain reaction: a future in clinical diagnostics. Med. Lab. Sci. 1992; 49:119-128
Lichtensteiger, CA, Steenbergen, SM, Lee, R.M, Polson, DD and Vimr, ER. Direct PCR analysis for toxigenic Pasteurella multocida .J. Clin. Microbiol .1996: 34: 3035-3039
Kumar, H, Sharma, S, Mahajan, V, Verma, S, Arora, AK, Kaur, P and Sandhu, KS. Pathology and PCR based confirmation of haemorrhagic septicemia outbreaks in bovines. Indian J. Vet. Pathol. 2006:30(1):5-8
Abdullah, FFJ, Khaleel, MM, Adamu, L, Osman, AY and Haron, AW Polymerase chain reaction detection of Pasteurella multocidatype B: 2 in mice infected with contaminated river water. Am. J. Anim. Vet. Sci. 2013: 8: 146-151
Kapoor, V, Katoch, RC, Sharma, M and Asrani, RK. Pathogenicity test of P. multocidain mice A:1. Indian J. Anim. Sci .2004: 74:495-496
Srinivas VMV, Parthiban S. Mukhopadhyay, HK and Antony, PX Pasteurella multocidainfection in Emu ( Dromaius novaehollandiae). Indian Vet. J. 2014; 91(6):09-12
Bhat MA, Darzi NM, Wari SA, Willayat M. Pathology of spontaneously occurring P. multocidainfections in pigeons. Indian J. Anim. Sci. 2002; 72:384-385
Choudhary M, Choudhary BK, Ghosh RC, Bhoyar S, Chaudhari S, Barbuddhe SB. Cultivable microbiota and pulmonary lesions in polymicrobial bovine pneumonia. Microbial Pathogenesis. 2019; 134:103577
Praveena, P E, Periasamy, S, Kumar, A A and Singh, N. Pathology of Experimental Infection by Pasteurella MultocidaSerotype A1 in Buffalo Calves. Vet. Pathol. 2014: doi:10.1177/0300985813516647
Sujatha K, Srilatha CH, Ahmed NN. An outbreak of pasteurellosis in pigs. Indian Vet. J. 2003; 80:341-343
Kumar H, Mahajan V, Sharma S. Concurrent pasteurellosis and classical swine fever in Indian pigs. J. Swine Health Prod .2007; 15(5):279-283
Das, SS and Bhagwan PSK. Isolation and characterization of P. multocidafrom ovine pneumonia. Indian J. Anim.Sci .1997:67:29-30
Ali S, Mahmoud MZ. Screening picture on pasteurellosis in a flock of sheep at Assiut Governorate. Assiut Vet. Med. J. 1993; 29(57):164-176
Pilla AG, Katiyar AK, Awadhiya RP, Vegad JL. An outbreak of pasteurellosis in swine. Indian Vet. J. 1986; 63:527-529
Katoch S, Sharma M, Patil, RD, Kumar, S and Verma, S. In vitroand in vivopathogenicity studies of Pasteurella multocidastrains harbouring different ompA. Vet. Res. Commun. 2014: DOI 10.1007/s11259-014-9601-6