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| + | Also known as: ''''' Torovirus '''''—'''''Torovirus infections '''''— ''''' Berne virus'''''—''''' BEV '''''— '''''Breda virus'''''—''''' BRV'''''—''''' Bovine torovirus'''''—''''' BoTV'''''—''''' diarrhea in calves'''''—''''' Equine torovirus'''''—'''''ETV'''''—'''''Prototype Berne virus'''''—''''' Porcine torovirus'''''—''''' |
| + | ==Introduction== |
| + | Toroviruses are relatively new viruses belonging to the family Coronaviridae. The viruses are enveloped positive sense single-stranded RNA (ssRNA) viruses that are pleomorphic, 120-140 nm in diameter and are relatively stable in acid or alkaline environment between pH 2.5-10. Toroviruses have been isolated from horses (Equine torovirus, ETV, prototype Berne virus) and calves with diarrhoea (bovine torovirus, BoTV, prototype Breda virus). |
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| + | ==Signalment== |
| + | Host include cattle, zebu, goats, horses, sheep, pigs, lagomorphs, rodents, domestic cats and humans. |
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| + | ==Clinical Signs== |
| + | The disease causes diarrhoea, pyrexia, dehydration, lethargy and depression in all ages of cattle. In calves it causes anorexia, mucoid faeces and the following neurological signs; generalised weakness, paralysis, inability to stand, trembling and sudden death. It can also cause respiratory problems such as laryngitis, tracheitis and pneumonia. Young, colostrum-deprived calves are particularly at risk. |
| + | In cats, diarrhoea and protruding nictating membranes have been associated with feline torovirus infections. |
| + | ==Epidemiology== |
| + | Toroviruses are found in many species but little is known about the transmission or interspecies transmission of the virus. It is presumed that it is spread via the faecal-oral route and spread through subclinical or chronically infected cattle <ref name=" Koopmans and Horzinek, 1994"> Koopmans, M., Horzinek, M.C., (1994). Toroviruses of animals and humans: a review. Advances in Virus Research, 43:233-273; many ref. </ref>. |
| + | The Berne virus(BEV) has been found in horses; whereas the Breda virus (BRV) is found in cattle of which there are two serotypes; BRV 1 and 2. Breda virus in cattle can be detected in the dome epithelium and enterocytes of the intestines and differentiate within the epithelial cells of the villi; interrupting the cattles absorptive capacity, although not as dramatically as the rotavirus. |
| + | Pigs can shed the torovirus without showing any symptoms of disease (Kroneman et al., 1998). Kroneman A, Cornelissen LAHM, Horzinek MC, Groot RJde, Egberink HF, 1998. Identification and characterization of a porcine torovirus. Journal of Virology, 72(5):3507-3511; 35 ref. |
| + | ==Distribution== |
| + | '''Worldwide''' in cattle and horses. |
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| + | ==Diagnosis== |
| + | Berne virus P138/72 is the only torovirus isolate to date (Cornelissen et al., 1998). Cornelissen LAHM, Woensel PAMvan, Groot RJde, Horzinek MC, Visser N, Egberink HF, 1998. Cell culture-grown putative bovine respiratory torovirus identified as a coronavirus. Veterinary Record, 142(25):683-686; 38 ref. The diagnostic methods include a combination of electron microscopy, immuno-electron microscopy (IEM), haemagglutination inhibition or ELISA. Toroviruses can be differentiated from coronaviruses by using IEM (Woode, 1987). Woode GN, 1987. Breda and Breda-like viruses: diagnosis, pathology and epidemiology. Novel diarrhoea viruses., 175-191; [Ciba Foundation Symposium 128]; 23 ref. |
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| + | Villus fusion and atrophy and thinning of intestinal wall can be seen on post-mortem. |
| + | ==Treatment== |
| + | There is no specific treatment. Animals can be supported with fluids to prevent dehydration as a result of the episodes of diarrhoea. Secondary bacterial infections can be treated with antibiotics. Culture and sensitivity recommended. |
| + | ==Control== |
| + | Isolation of infected animals and good hygiene and sanitary measures may help reduce the spread of the disease. |
| + | ==References== |
| + | <references/> |
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| + | {{Learning |
| + | |flashcards = [[Blue Eye Disease Flashcard]] |
| + | }} |
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| + | [[Category:To Do – CABI review]] |
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