Outbreak of Newcastle disease due to pigeon paramyxovirus type I in grey partridges (Perdix perdix) in Scotland in October 2006

In October 2006, following an initially non-statutory disease investigation affecting 12-week-old grey partridges (Perdix perdix), an outbreak of Newcastle disease due to infection with the avian paramyxovirus type I virus responsible for the current panzootic in pigeons (PPMV-I) was confirmed in Scotland. Two pens of partridges were affected by signs including loss of condition, diarrhoea, progressive neurological signs and mortality totalling approximately 24 per cent, and laboratory evidence of the infection was obtained only in these groups. The premises had approximately 17,000 poultry including a collection of 375 birds of rare breeds, containing endangered breeds of significant conservation value, which were not culled but subjected to a health monitoring and testing programme. Investigations suggested that a population of feral pigeons living above the affected pens of partridges was the likely source of the outbreak. Laboratory and genetic analyses confirmed that the isolate recovered from the clinically affected partridges was PPMV-I, belonging to genetic lineage 4b. However, the virus could not be isolated from or detected in dead pigeons collected from the affected buildings.