Immunohistochemical and molecular detection of natural cases of bovine rotavirus and coronavirus infection causing enteritis in dairy calves

Abstract

A B S T R A C TBovine rotavirus (BRoV) and bovine coronavirus (BCoV) are major enteric viral pathogens responsible for calve diarrhoea. They are widespread both in dairy and beef cattle throughout the world and causing huge economic losses. The diagnosis of these agents is very difficult due to non-specific nature of lesions and the involvement of some intrinsic and extrinsic risk factors. We performed postmortem of 45 calves, which was below three months of age. Out of 45 necropscid calves, three (6.66%) cases were positive for BRoV and four (8.88%) cases were found positive for BCoV, screened by reverse transcriptase polymerase chain reaction (RT-PCR). Further RT-PCR positive cases were confirmed by immunohistochemistry (IHC) in paraffin-embedded intestinal tissue sections. Three cases of enteritis caused by BRoV showed the hallmark lesions of the shortening and fusion of villi, denudation and infiltration of mononuclear cells in the lamina propria. The BRoV antigen distribution was prominent within the lining epithelium of the villi, peyer's patches in the ileum and strong immunoreactions in the lymphocytes and some macrophages of the mesenteric lymph nodes. Four cases in which BCoV was detected, grossly lesions characterized by colonic mucosa covered with thick, fibrinous and diphtheritic membrane. Histopathologically, jejunum showed skipping lesion of micro-abscesses in crypts. The BCoV antigen distribution was prominent within the necrotic crypts in the jejunum and cryptic micro-abscesses in the colon and ileum. It is the first report of BRoV and BCoV antigen demonstration in the jejunum, colon, ileum, Peyer's patches and mesenteric lymph nodes of naturally infected calves from India by using IHC.

Bovine coronavirus in neonatal calf diarrhoea in Iran

“…For example, Pérez et al., (1998) in Costa Rica using DOT‐ELISA, found that coronavirus was present in stool samples of 7% of scouring calves. In another study in India from 45 necropsied calves, four (8.88%) cases were found to be positive for coronavirus according to RT‐PCR (Singh et al., 2020). Castell et al., (2019) in Uruguay using real‐time polymerase chain reaction (PCR) targeted the S gene, detected BCoV in 7.8% (64 of 824 samples) of faeces (763) and intestinal contents (61) from beef and dairy cattle.…”

Pathology of Coronavirus Infections: A Review of Lesions in Animals in the One-Health Perspective

“…Boileau and collaborators deeply revised the literature on BCoV infections and observed that both BeCoV-CD and BeCoV-WD are associated with similar intestinal lesions, with muco-hemorrhagic enterocolitis being the main gross finding [ 73 , 82 , 83 ]. Mesenteric and ileal lymph nodes can be enlarged and congested [ 84 ]. The spiral colon is edematous and fluid-filled [ 82 ] with petechiae, ulcers, and diphtheritic membranes that can show a segmental distribution [ 82 , 83 , 84 , 85 ].…”

“…Mesenteric and ileal lymph nodes can be enlarged and congested [ 84 ]. The spiral colon is edematous and fluid-filled [ 82 ] with petechiae, ulcers, and diphtheritic membranes that can show a segmental distribution [ 82 , 83 , 84 , 85 ].…”

“…In experimentally infected calves, the lesions appear to progress from the duodenum to jejunum, ileum, cecum, colon, and rectum [ 87 ]. Microscopically, the mesenteric lymph nodes show moderate depletion of cortical follicles or even necrosis of the follicles [ 84 ]. The mesenteric vessels’ tunica media may expand because of abundant edema, fibrin, neutrophils, lymphocytes, histiocytes, and plasma cells (vasculitis) [ 82 ].…”

“…The small intestine shows sloughed villi, villous atrophy, widespread villous fusion, increased crypt depth, crypt micro-abscesses (similar to equine CoV), hyperplasia of crypt lining cells, and an engorged or hemorrhagic lamina propria infiltrated by mononuclear cells [ 84 , 87 ]. In the large intestine, the most common lesion is acute hemorrhagic colitis.…”