The Pathogenesis of Proventricular Dilatation Disease Caused by Parrot Bornaviruses: A Possible Role For Neuropeptide Y (Npy)

Abstract Background Psittacine Bornaviruses cause a unique disease syndrome in parrots and related birds. Known as proventricular dilatation disease (PDD), it is characterized by massive dilatation of their proventriculus as a result of excessive food accumulation within that organ. This leads to gastric obstruction and eventually, to death by starvation. Results In a preliminary study on the transcriptome of psittacine bornavirus-infected human astroglia it was noted that the gene encoding neuropeptide Y was significantly upregulated. In a subsequent study of cockatiels experimentally infected with the same strain of psittacine bornavirus, their brains were examined by RNA-seq to determine which genes were being actively transcribed. It was confirmed that among the genes whose expression was significantly increased relative to control, uninfected birds was that for neuropeptide Y. Conclusions Neuropeptide Y is known to cause overeating in birds. We hypothesize therefore that the clinical manifestations of proventricular dilatation disease are a result of the excessive production of neuropeptide Y by bornavirus-infected brain cells acting in association with damage to the neurons of the proventricular myenteric plexus.