Pheasant ataxia: a new condition in pheasant poults

Abstract

Between 1995 and 1997 a neurological condition in pheasant poults from 24 sites in England and Scotland was investigated. Affected birds showed varying degrees of ataxia and incoordinated movements and, in severe cases, recumbency, but generally remained alert with their heads held upright. The condition characteristically affected poults from seven weeks of age and the incidence on any one site was low. No significant bacteria were isolated consistently from brain tissue. The condition was characterised histologically by a non-suppurative meningoencephalitis, in which lesions were found predominantly in the cerebellum in 61 of 81 samples examined (75.3 per cent). A non-suppurative myelitis was recorded in 16 of 20 spinal cords examined. No lesions were recorded in peripheral neural tissue and lesions were rare in other tissues. The condition appeared not to have been recorded previously in pheasants. A viral aetiology was suspected but Newcastle disease virus was not involved.

Pheasant ataxia in England

“…In this case, the birds presented with clinical signs suggesting pheasant ataxia and histopathology of the brain showed the typical nonsuppurative encephalitis. In contrast to the birds initially reported by Welchman and others, 1 all birds examined on this estate had large numbers of Ixodes ricinus ticks in the periocular area; the role of ticks in the disease remains uncertain.…”

“…PHEASANT ataxia is a condition of unknown aetiology which was first described in British pheasants ( Phasianus colchicus ) in the 1990s 1 . The disease is a clinicopathological entity which is characterised by various degrees of ataxia in pheasants while the birds remain alert and bright; this latter observation is important to note as it differentiates the disease from other neurological conditions.…”

Disease surveillance in England and Wales, May 2021

“…The clinical history and the distribution of the brain lesions were those typically observed in cases of pheasant ataxia reported previously 5 . The character of the brain lesions is consistent with an infectious cause, though the exact aetiology of pheasant ataxia is unknown.…”

Newcastle disease outbreaks in domestic fowl and turkeys in Great Britain during 1997

“…However, an examination of 68 pheasants shot in the vicinity of outbreak 1 failed to yield Newcastle disease virus and there were no reports of abnormal deaths of pheasants in the relevant areas. Newcastle disease had been one of the presumptive diagnoses for ataxia in pheasants reported from various locations in Great Britain between 1995(Pennycott 1997, Welchman and Ainsworth 1997, but repeated attempts to isolate Newcastle disease virus from affected pheasants have failed and the aetiology of the condition remains unknown. Pheasants are imported from Denmark into Great Britain but usually as embryonated eggs, and the presence of virulent Newcastle disease virus should be identified early.…”