The pathogenesis of proventricular dilatation disease

Abstract

Bornaviruses cause neurologic diseases in several species of birds, especially parrots, waterfowl and finches. The characteristic lesions observed in these birds include encephalitis and gross dilatation of the anterior stomach - the proventriculus. The disease is thus known as proventricular dilatation disease (PDD). PDD is characterized by extreme proventricular dilatation, blockage of the passage of digesta and consequent death by starvation. There are few clinical resemblances between this and the bornaviral encephalitides observed in mammals. Nevertheless, there are common virus-induced pathogenic pathways shared across this disease spectrum that are explored in this review. Additionally, a review of the literature relating to gastroparesis in humans and the control of gastric mobility in mammals and birds points to several plausible mechanisms by which bornaviral infection may result in extreme proventricular dilatation.

Memory Impairment Induced by Borna Disease Virus 1 Infection is Associated with Reduced H3K9 Acetylation

“…BoDV-1 was recently identified as the cause of human death after organ transplantation -the first hard evidence that BoDV-1 can actually infect humans and cause disease [6]. BoDV-1-infection may induce a large spectrum of neurological disorders ranging from immune-mediated acute encephalitis to non-inflammatory behavioral alterations [7,8]. Previous studies demonstrated that BoDV-1 establishes a persistent infection in the hippocampus and limbic lobe of rodents in the neonatal period, which induced cognitive deficits and mental disorders [4,9].…”

Bornaviruses in naturally infected Psittacus erithacus in Portugal: insights of molecular epidemiology and ecology

“…Regarding the parrot B240818, the source of infection is unknown; however, we suspect that parrot bornavirus 4 (PaBV-4) entered via the olfactory pathway and migrated to brain [18], causing a lethal encephalitis; without neurological signs perceptible by the owner. The absence of clinical signs in bornavirus-infected parrots with brain lesions has previously been reported [18].…”

“…Regarding the parrot B240818, the source of infection is unknown; however, we suspect that parrot bornavirus 4 (PaBV-4) entered via the olfactory pathway and migrated to brain [18], causing a lethal encephalitis; without neurological signs perceptible by the owner. The absence of clinical signs in bornavirus-infected parrots with brain lesions has previously been reported [18]. Therefore, in this case, probably the virus followed one of the postulated pathways, which consist of the centrifugal spread of virus from brain, passing down the spinal cord, affecting the parasympathetic and sympathetic nerves and the organs innervated by them (e.g.…”

“…In Psittaciformes, parrot bornavirus 1 to 8 (PaBV-1 to 8) can cause proventricular dilatation disease (PDD), characterized by a flaccid and distended proventriculus impacted with feed, as a result of the inability of seeds' digestion (however throughout the gastrointestinal tract can occur variable distention) [18]. Psittaciformes can also show uncoordinated movements, postural disorders, apathy, blindness, and behavioural disorders, such as loss of appetite [1].…”

“…ABBV-1 to 2 = aquatic bird bornavirus 1 to 2, BoDV-1 to 2 = Borna disease virus 1 to 2, CnBV-1 to 3 = canary bornavirus 1 to 3, EsBV-1 = estrildid finch bornavirus 1, JCPV = jungle carpet python virus. LGSV-1 = Loveridge's garter snake virus 1, SWCPV = southwest carpet python virus, PaBV-1 to 8 = parrot bornavirus 1 to 8, VSBV-1 = variegated squirrel bornavirus 1. and self-mutilation (resulting from lesions in the central nervous system) [18]. Within captive birds, the virus has become relevant for Psittaciformes housed in reserves, in breeding projects of rare species, in private collections and zoos, because of the severe effects it may cause for bird welfare, economy, and biodiversity levels.…”