Detection of the disease
Since mid-2016, high levels of mortalities in kept pigeons (racing and fancy) occurred in lofts across most states of Australia. Emergency animal diseases and notifiable diseases, such as avian influenza (AI), Newcastle disease virus (NDV) and pigeon paramyxovirus virus type 1 (PPMV1), were ruled out as the cause. Investigations of these events found they were due to a rotavirus (a member of the reoviridae family).
In March 2017, pigeon rotavirus was detected in sick pigeons in Tasmania.
Figure 1: Clinically affected and dead pigeons, noting evidence of green diarrhoea (Images provided by Dr C Walker)
Clinical signs in affected birds have included depression and reluctance to go out and fly, vomiting, diarrhoea, regurgitation and hunched postures. Birds that appear sick often die within 12 to 24 hours, with deaths in affected lofts continuing for approximately 7 days (Figure 1).
Mortality rates of up to approximately 30% have been reported in affected lofts. While the history of the pigeon rotavirus outbreak on the mainland indicates there may be a lengthy carrier status for recovered birds of some weeks or months, the full nature of the disease is yet to be elucidated.
Other susceptible birds
Feral pigeons are likely to be susceptible to the virus. Any signs of disease that are unusual or clusters of deaths in wild birds should be reported. In Western Australia, feral pigeon (rock pigeon;
Columba livia) mortalities occurred in a location close to an affected loft, with gross and histological findings consistent with the disease in the racing and fancy pigeons. In addition, rotavirus has been detected in faecal samples of several feral and native wild bird species overseas.
The risk to the commercial poultry sector has been considered low based on field experience. At this stage, no challenge testing for pigeons is planned.
The potential role of vaccination
There is currently no indication that the PPMV1 vaccine was involved with this rotavirus disease and pigeon owners should continue with their PPMV1 vaccination schedule.
Rotavax, an unregistered vaccine, has been developed in Australia and is currently permitted for use by registered veterinarians, or caged pigeon owners on an emergency basis, pending efficacy data. The vaccine has been in use in Tasmania since June 2019.
Australia has a rigorous regulatory framework for assessing and approving veterinary vaccines to ensure their safety and efficacy. It is not yet known whether the Australian-developed pigeon rotavirus vaccine will prevent rotavirus infection or disease in pigeons.
The pigeon industry is advised to continue implementing biosecurity measures to prevent the spread of the disease. This includes reconsidering gatherings and movements (including racing) of pigeons, and practicing good personal biosecurity. The squab industry should also take appropriate measures.
Biosecurity recommendations for the pigeon industry include:
- avoid mixing pigeons (for example, racing, shows, sales) from unaffected and affected lofts. Even if the rotavirus vaccine is found to be effective, implementation of biosecurity measures for lofts, and any event where pigeons may mix, will be important;
- any pigeon fancier whose loft has been affected by rotavirus infection should maintain strict biosecurity measures, including not selling pigeons to unaffected lofts, loft hygiene and visitor restrictions to prevent the spread of the rotavirus;
pigeon fanciers with unaffected lofts should maintain strict biosecurity measures, including no pigeon introductions from affected lofts, cleaning and disinfection of second hand equipment, visitor restrictions and cleaning clothing/boots after contact with other pigeons to prevent entry and spread of the rotavirus.
Private veterinarians are reminded to be particularly mindful of biosecurity when visiting pigeon lofts and when pigeons are presented for clinical examination.
Additional general biosecurity resources are also available and include:
It is important for bird keepers and others to continue to report any suspicious signs of disease. This will also allow the presence of notifiable diseases, including AI, PPMV1 and ND, to be investigated and ruled out.
Reporting sick birds
You can report sick birds (domestic, feral or native) with unusual signs, including higher than usual numbers of deaths, to:
Note: this information has been developed in consultation with relevant State, Territory, Commonwealth Government agencies and Wildlife Health Australia for use as a resource document.