Total of 90 samples of each organ
i.
e. liver, lungs, kidneys, heart, spleen and 35 intestine samples were collected randomly from the Government slaughterhouse, Aizawl, Mizoram during the study period. Intestine samples were less in number because of the reason that intact intestine is used for the preparation of a local delicacy in Mizoram. The incidence percentage of both gross and microscopic lesions of each organ were represented in Fig 1. Incidence of different gross lesions in all organs were given in Table 1.
Liver
Liver was found to the most common organ in which either a gross or histopathological lesions were found during the present study. The incidence per cent of different histopathological lesions were given in Fig 2. The major gross lesion found in liver included shrunken and nodular lesions (Fig 3A), fatty liver, hepatomegaly, hydatid cyst, abscess and Amphistomiasis. Among the microscopic lesions degenerative changes was found to be the most common lesion as compared to other conditions. Degenerative changes observed include cloudy swelling, hydropic degeneration and fatty changes whose microscopic findings correlated well with the standard descriptions reported earlier. Necrosis found in liver was of either coagulative or caseous type with calcifications
(Vegad and Swamy, 2010). Bile duct hyperplasia was indicated by proliferation of new biliary duct around the portal area with infiltration of mononuclear cell (Fig 3B) and the bile canaliculi cell was indicated by Luna-Ishak stain (Fig 3C) which was also reported previously
(Laven et al., 2004). Liver with fibrosis showed proliferation of fibrous connective tissues with infiltration of inflammatory cells (Fig 3D) and hepatitis was indicated by presence of congestion and haemorrhages with inflammatory cells (Fig 3E). Microscopically, cirrhotic liver was indicated by presence of island of degenerating and necrotic hepatocytes with infiltration by mononuclear cells in between the excessively proliferating fibrous connective tissues (Fig 3F).
El-Dakhly et al., (2007) and
Raji et al., (2010) also reported similar findings in cirrhosis cases in their studies. One case showed presence of multiple abscess formations with thick purulent masses (Fig 3G), which was also observed in previous study
(Ahmed et al., 2013). In Amphistomiasis, liver became hard with thickened bile duct (Fig 3H) and microscopically, infiltration of reactive cells with moderate fibrosis was observed. The same type of lesions was observed in previous study
(Ahmedullah et al., 2007). In one case, shrunk and constipated hydatid cyst was observed and histopathological changes included presence of laminated wall and hepatic degeneration with infiltration by mononuclear cells in between cyst wall and liver parenchyma (Fig 3I) which was in accordance with previous report
(Mekuriaw et al., 2016).
Lungs
The incidence percent of different histopathological lesions were presented in Fig 4. Interstitial pneumonia was the most common as compared to other types. Other than pneumonia hemosiderosis, emphysema, anthracosis and hydatid cyst formation were the other microscopic lesions encountered. In a study by
Ahmed et al., (2013), the author reported congestion (6.5%), lung abscesses (9.4%) and pneumonia (28.7%) as the common findings.
Mekuriaw et al., (2016) reported emphysematous lungs were non collapsible with pale or white patches and microscopically, there was diffuse, distended and broken alveoli (Fig 5A) which was also found in emphysema cases during this study. Improper stunning, delayed slaughter after stunning may also contributed to emphysema in lungs
(Kusiluka and Kambarage, 1996). Cases with bronchopneumonia, anterior and ventral portion of lungs were severely affected as compared to other parts. There was also congestion and hemorrhages with areas of consolidation and hepatisation (Fig 5B). In interstitial pneumonia, mottling of lungs with thickened interalveolar septa was observed. Bronchopneumonia was indicated by presence of congestion along with serous exudates and inflammatory reactions surrounding the bronchus (Fig 5C). In interstitial pneumonia, thickening of interalveolar septa with infiltration of inflammatory cells predominantly mononuclear types with varying degree of serous or fibrinous exudates could be observed (Fig 5D). In aspiration pneumonia, there was presence of severe congestion, hemorrhages and serofibrinous exudates in the lungs parenchyma (Fig 5E). Verminous pneumonia with hydatid cyst was observed in one case. Microscopically, there was presence of laminated cyst wall surrounded by proliferation of connective tissues (Fig 5F). The gross and histological lesions associated with each of these types of pneumonia correlated well with the lesions previously reported by other research
(Caswell and Williams, 2007;
Dar, 2011). Bronchopneumonia was most often associated with
P.
multocida infection, although other respiratory bacteria may also produce the same lesions
(Caswell and Williams, 2007). Pneumonia is important in animals because of extreme weather conditions during dry season and verminous pneumonia in rainy season. One case of hydatid cyst was observed in the present study which was also reported by earlier workers like
Islam et al., (2014) and
Belkhiri et al., (2009). Anthracosis was indicated by presence of black colour deposits in the lungs parenchyma (Fig 5G) which was also recorded by
Rahman et al., (2006). Hemosiderin pigments were observed as brownish yellow granules inside macrophages which was confirmed by Perl’s Prussian blue staining (Fig 5H). This correlated with the findings of
Jongsam et al., (2002).
Kidney
The major gross changes included circulatory disturbances followed by a case of necrosis, cystic kidney. The incidence % of different histopathological lesions were presented in Fig 6. In one case, there was presence of solitary cyst of 4 cm diameter containing clear fluids (Fig 7A). On histopathological examination, indistinct cyst wall separated by a zone of proliferating connective tissues surrounded by a zone of infiltrating mononuclear cells separating the kidney parenchyma from the cyst was observed (Fig 7B).
Tavassoly (2003) also reported the presence of cystic kidney conditions in his study. Among the histopathological lesions tubulo-interstitial nephritis was the most common finding other than the circulatory disturbances. The other important lesions included glomerulonephritis, degenerative changes in the tubular epithelial cells and necrosis of renal parenchyma along with calcification and fibrosis. A study done by
Vikas and Deepika (2016) revealed that congestion (57.14%), haemorrhages (29.42%) and necrotic foci (14.29%) as the common findings in kidney.
Raji et al., (2010) reported that there was prevalence of abscesses (4.55%) and hydronephrosis (0.08%).
Ahmed et al., (2013) investigated kidneys of cattle in Ismailia abattoir, Egypt and revealed that there were kidney cysts (6.9%), hydronephrosis (1.6%), white spots (6.7%), fibrosis (2.6%) and pyelonephritis (3.6%) led to the condemned kidneys. Tubulo-interstitial nephritis was more common as compared to glomerulonephritis. In tubulo-interstitial nephritis, infiltration of inflammatory cells was observed surrounding the tubule and in the interstitial spaces of the kidney parenchyma along with congestion and haemorrhages (Fig 7C) whereas in glomerulonephritis, infiltration of inflammatory cells (Fig 7D) and mesangial cell hyperplasia was found in the glomerulus. Similar lesions associated with tubule-interstitial nephritis and glomerulonephritis were also reported by different other studies
(Vegad and Swamy, 2010;
Ahmed et al., 2013). Glomerulonephritis may be seen in the infection of
Coliforms,
Leptospira (Sharma
et al., 2022),
Streptococci,
Staphylococci,
Pasteurella and Salmonella (Jubb
et al., 1993). Interstitial nephritis may occur due to toxicities of ochratoxins, atrinin and pesticides or due to leptospirosis, Herpes virus
etc.
(McGavin et al., 2001). Degenerative changes were also observed with sloughing of tubular epithelium in the present study which were also reported by previous report
(McGavin et al., 2001). Calcification was confirmed by Von Kossa stain (Fig 7E) whereas proliferated collagen fibres in fibrosis was stained with Masson’s trichrome stain (Fig 7F). The same reports were recorded by
Tavassoly (2003).
Heart
The incidence % of different histopathological lesions were presented in Fig 8. Mainly congestion and hemorrhages in epicardium (Fig 9A) and endocardium (Fig 9B) were observed in heart. Myocarditis characterised by infiltration of mononuclear cells in between muscle fibres (Fig 9C) was observed in few cases in the present study. Myocarditis may occur in diseases like Pasteurellosis, FMD, Blackleg, Listeriosis, Tuberculosis
etc.
(Kumar et al., 2007). Pericarditis was observed in few cases in which congestion and infiltration of the pericardium with inflammatory cells was observed.
Sastry and Rao (2013) reported that pericarditis may be observed in diseases like Pasteurellosis, Coliform infections and Tuberculosis. Presence of Sarcocyst in the myocardium (Fig 9D) was most commonly observed in my study period, which could be attributed to the wet and moist agro-climatic conditions prevailing in this region and myocardial necrosis was observed in one case. Similar observations were also reported in the previous studies
(Seema et al., 2007).
Spleen
Like heart, except for congestion and abscess formation no other gross lesion was observed in spleen. The incidence % of different histopathological lesions were presented in Fig 8A. Among the microscopic lesions, spleen showed lesions associated with circulatory disturbances, splenitis and suppurative necrosis and fibrous encapsulation. Splenomegaly was indicated by rounding of edges with congestion and the spleen was soft in consistency.
Gracey et al., (1999) described the same lesions in spleen was due to blood parasite infestations. Splenitis and circulatory disturbances were found more commonly in the present study. Microscopically, splenitis was indicated by presence of necrosis in red pulp areas with congested blood vessels and neutrophilic infiltrations. In some cases, there was proliferation of reticuloendothelial cells with severe macrophages infiltrations in red pulp areas (Fig 9E). Grossly, one large abscess with thick pus was observed in one case (Fig 9F). Abscess formation may be of bacterial infections which is aggravated due to migrating intestinal parasite
(Rosa et al., 1989). In the case of abscess, severe fibrous tissue proliferation with neutrophilic infiltrations separating the splenic parenchyma from the abscess cavity could be observed (Fig 9G). Same results were reported earlier
(Jubb et al., 1993). Splenitis may occurs due to hemoparasitic infections (Anaplasmosis, Babesiosis and Theileriosis) and also in Salmonellosis, Anthrax, Tuberculosis, Pseudotuberculosis and Actinomycosis
etc.
(Maxie et al., 2007).
Intestine
The major gross changes found in intestine was congestion of the mucosa and some cases showed haemorrhages. The incidence % of different histo-pathological lesions were presented in Fig. 8B. Erosion and ulcer formation was observed in one case (Fig 9H). Enteritis was the most common microscopic findings during the study period. There was sloughing of villous epithelial cells with inflammatory cells in the lumen of intestine and in some cases mild to severe infiltration of mononuclear cells in the mucosa and submucosa (Fig. 9I). Degeneration and necrosis of mucosa and crypt epithelial cells were also observed. Similar findings were reported by
Cho and Yoon (2014). Several aetiologies are responsible for enteritis in bovines which include chemicals, bacteria, viruses, protozoa, rickettsia, helminths, fungi, metabolic disorders
etc.
(Kashyap et al., 2017).
Study about abattoir slaughter is crucial for understanding the public’s exposure to zoonotic diseases and estimating financial losses caused by the condemnation of affected organs
(Chhabra and Singla, 2009). Different affected organs were condemned during the slaughter which causes huge financial losses during this study periods. Some zoonotic diseases may be fatal in human beings if they will eat the affected meat. Therefore, a slaughter house study helps in the assessment of the disease status of herds and also prevents distribution of the infected meat to human being
(Mellau et al., 2010).
