Reovirus infections associated with high mortality in psittaciformes in the Netherlands.
Résumé
In the Netherlands, between January 2002 and December 2004 numerous psittaciformes died showing severe spleno- and hepatomegaly with multifocal acute necrosis. At the start of the outbreaks mostly parakeets were affected, but later larger parrots were also involved. 78 birds showed the same features and six animals were completely examined including virological examination. Tests for polyomavirus, Pacheco's disease (herpesvirus) and circovirus (PBFD) viruses and Chlamydophila psittaci were carried out. All results were negative, except for two cases of circovirus infection. Many concurrent bacterial and parasitic infections were seen. Immunohistochemistry revealed reovirus antigen in intralesional mononuclear cells and by negative contrast electron microscopy reovirus-like particles could be observed. A reovirus was grown and the isolates reacted with polyclonal reovirus antiserum but did not react with monoclonal antibodies against chicken reovirus. Therefore the virus was considered a psittacine reovirus. Because reoviruses were seen consistently, they seemed to be the most likely cause. The climate, the introduction of new birds and the transportation of birds might be the factors involved in the disease in the Netherlands. No regional influence could be seen, therefore we suggested that the virus might be widespread and carriers could be a source of re-introduction.
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