Racing pigeon mortality in Victoria
A disease affecting racing pigeons in Victoria was first reported in late December 2016. This outbreak appears to have followed the aggregation of pigeons at a sale in Kyabram in the north of the state.
Birds in affected lofts exhibited vomiting, developed green diarrhoea and assumed a hunched posture. All sick birds usually died within 12 to 24 hours. Deaths in affected lofts continued for approximately seven days with affected lofts experiencing mortalities of up to 30%.
Similar recent outbreaks were reported in South Australia, New South Wales and Western Australia.
Affected birds submitted to the Agriculture Victoria laboratory, AgriBio, showed signs of severe hepatitis, coalescing hepatocyte degeneration and necrosis, enlarged/pale spleens with severe depletion of lymphoid tissue and reduction in the size of the cloacal bursa.
Emergency animal diseases and notifiable diseases, such as avian influenza and pigeon paramyxovirus (PPMV1), were ruled out.
Reovirus was identified in large quantities in liver tissues by histology and confirmed by PCR testing at the University of Melbourne and negative contrast electron microscopy at the Australian Animal Health Laboratory(AAHL) in Geelong (Figure 2).
The virus has subsequently been identified as a rotavirus (within the genus Reoviridae). This is the first time that this virus has been identified in pigeons. Interestingly, this rotavirus predominantly affects the liver unlike other rotaviruses that typically affect the intestine.
Although no treatments are currently available for rotavirus in pigeons, work is underway to develop a vaccine. In the meantime, the Victorian racing pigeon industry has instituted a voluntary halt to racing or other events where birds and fanciers may congregate.
Practitoners should remain vigilant for disease events in pigeon lofts and are requested to continue to submit samples that will allow exclusion of emergency animal diseases and notifiable diseases, such as avian influenza and pigeon paramyxovirus.