Vaccinating pigeons against avian paramyxovirus
Avian paramyxovirus type 1 in pigeons was first detected in Australia in August 2011 and appears to have become established in Victoria.
Since May 2012, it has also been confirmed in a number of flocks in New South Wales.
It is likely to eventually affect pigeons in Queensland.
It is vital to maintain good preventative biosecurity to protect pigeons from infection. Vaccination is just one of those prevention options.
Vaccination
There is currently no registered vaccine for use in pigeons in Australia. However, there are vaccines registered in Australia for use in fowl against Newcastle disease, which is a closely related virus.
Vaccinating pigeons with Newcastle disease vaccine may reduce the impact of infection, and may provide a useful adjunct to biosecurity in minimising the potential damage caused if the disease spreads into Queensland.
Vaccination should only be used in flocks that are healthy. If used in an infected flock, it may protect against some clinical signs but it would not entirely prevent the spread of infection to other in-contact birds.
Safety and efficacy
There is very little Australian data on the use of the Newcastle disease vaccines to show they are safe to use in pigeons or will protect pigeons against infection with avian paramyxovirus.
Overseas experience has demonstrated good protection against clinical signs of paramyxovirus in pigeons by some poultry vaccines. However, there are differences in the virus strains between the vaccine and the pigeon-specific avian paramyxovirus.
These differences may result in a failure to protect pigeons, partial protection or a much shorter duration of protection than expected, especially with the live vaccine.
Vaccination, particularly with the killed vaccine, can pose risks to pigeons, including overdosing, injecting into the muscle, or bacterial infection at the injection site. Accidental self-inoculation can cause a severe local reaction in people.
Pigeon owners should discuss the potential risks and benefits of vaccination with their veterinarian, bearing in mind vaccination is neither guaranteed nor immediate.
Available vaccines
Newcastle disease vaccines that are registered in Australia are either live or killed (inactivated). They are intended for vaccination of large numbers of fowl in commercial flocks.
Live vaccines
The live vaccines for Newcastle disease in Australia contain a mild strain known as V4. In fowl, this strain causes little or no disease but still generates immunity, although usually of short duration.
Live vaccines are easy to administer to large numbers of birds, either by eye drop or by mouth. If given in drinking water, it must be consumed within 2-3 hours of being mixed, so water is usually withheld for a period prior to administration.
It usually comes in a freeze-dried tablet form and must be kept frozen until used. It must be mixed with a diluent and shaken well to completely dissolve the tablet before administration.
Live V4 vaccines may be available in 1000, 2000, 3000, 4000 and 5000-dose vials.
Killed vaccines
A killed or inactivated vaccine contains a strain of virus known as La Sota that has been killed. The vaccine also contains adjuvants to stimulate stronger and longer lasting immunity than is achieved by live vaccines. These adjuvants can also cause adverse reactions.
This vaccine has to be injected into the bird. For fowl it is injected into the breast muscle but this may not be a suitable site for pigeons. Preferred injection sites for pigeons are the loose skin at the base of the neck or between the leg and the body.
The killed vaccine must not be frozen. It should be kept at the manufacturer´s recommended temperature (usually between 4-8 degrees celsius).
Inactivated vaccines may be available as a 250 or 1000-dose bottle.
Vaccination procedure
In fowl, both live and killed vaccines are administered. The live vaccine is administered first and followed with a killed vaccine 4-6 weeks later. However, either of the vaccines may be used on its own.
The nationally recommended approach for pigeons is to use two doses of killed vaccine 2-4 weeks apart in healthy birds by subcutaneous injection.
As there is no data on the use of Australian vaccines except in fowl, it is not known whether or for how long vaccinated pigeons will be protected. An annual booster may provide greater assurance of ongoing protection.
As vaccines work by stimulating immune protection, they can take some weeks to take effect. Newcastle disease vaccine cannot treat pigeons already exposed or infected, nor provide maximum protection until at least a few weeks until after the vaccination procedure has been completed.
Should a person be accidentally injected, immediate first aid and medical attention should be provided. Refer to the Material Safety Data Sheet in the vaccine pack for details.
Access to vaccine
The use of Newcastle disease vaccine in pigeons is not covered by the provisions of its registration, because it is registered for use only in fowl.
By law, such ´off-label´ use is permitted only under written instructions from a veterinary surgeon and where the pigeons to be vaccinated are under the care of the veterinary surgeon.
The veterinary instructions must be given to the end user and must include specific information on vaccine dose, how many doses and how far apart, route of administration and details of birds to be vaccinated. Additional restrictions may apply if pigeons are used for food production.
The use of Newcastle disease vaccine in fowl is regulated and requires a permit from Biosecurity Queensland. However, no permit is required for use on pigeons in Queensland.
Disease control
Vaccination is just one tool in a suite of controls used to manage the risk of avian paramyxovirus in pigeons.
Due to a lack of scientific data, Biosecurity Queensland can not guarantee that such vaccination will be effective or safe.
While vaccination may assist in mitigating the risk and impact of disease spread within pigeon flocks and lofts, pigeon owners are strongly advised to implement biosecurity measures as the primary defence against avian paramyxovirus.
Any person who suspects that birds may have avian paramyxovirus should immediately contact a veterinarian and Biosecurity Queensland.