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First Case of Myocarditis Associated with Reovirus

by 5m Editor
3 March 2010, at 12:45p.m.

US - Researchers from the University of California, Davis, have reported what they believe to be the first case of an association between myocarditis in turkey poults and reovirus.

H.L. Shivaprasad and colleagues from the California Animal Health and Food Safety Laboratory System at the University of California, Davis, report the breakthrough in the current issue of Avian Diseases.

They say that myocarditis associated with reovirus was diagnosed in 17-day-old, male turkey poults, based on virus isolation, reverse transcriptase-polymerase chain reaction (RT-PCR), demonstration of reovirus antigen in the cytoplasm of mononuclear inflammatory cells and myocytes in the heart by immunohistochemistry (IHC), and reovirus particles in the endoplasmic reticulum of myocytes by transmission electron microscopy (TEM).

Clinical signs in the poults included anorexia, growth depression and increased mortality.

Gross lesions in the six poults examined were increased pericardial fluid, mild-to-moderate dilation of right ventricles, pale-yellow myocardium and ascites. Other lesions in a few birds included mild pulmonary oedema, congestion and pale serosa of the small intestine that had watery contents in their lumens.

Microscopically, in the heart, there was mild-to-severe necrosis of myocytes and infiltration of primarily lymphocytes mixed with a few heterophils, macrophages, and occasionally, plasma cells and multi-nucleated giant cells. There was mild-to-moderate lymphoid depletion in the bursa of Fabricius.

Reovirus was isolated from the heart of the turkey poults in chicken-embryo liver cells and was confirmed by RT-PCR, IHC, and TEM. A retrospective search of the laboratory database for cases of myocarditis associated with reovirus in turkeys revealed that this condition has occurred sporadically in California turkey flocks since 1991.

This is the first documentation of myocarditis in turkey poults associated with reovirus, conclude Shivaprasad and co-authors.

Reference

Shivaprasad H.L., M. Franca, P.R. Woolcock, R. Nordhausen, J.M. Day and M. Pantin-Jackwood. 2009. Myocarditis associated with reovirus in turkey poults. 2009. Avian Diseases 53 (4): 523–532. doi: 10.1637/8916-050309-Reg.1.

Further Reading

- You can view the full report by clicking here.