By Dr Colin Walker BSc, BVSc, MRCVS, MACVSc (Avian health)

Vaccination technique
When you receive your pigeon pox vaccine, you will find a small bottle with a dry orange pellet in its base, and either a second bottle or capped syringe containing a clear liquid. All should be stored in the freezer (not the fridge) until use. When it comes time to vaccinate the birds, take the tops off the bottle or syringe and pour the liquid on top of the orange pellet. This will dissolve over about 1 minute. The result is a thick orange liquid, not unlike tomato soup. This is the vaccine. The best place to vaccinate the birds is on the outside of the thigh. Avoid using the skin over the breast muscles – it is too easy to push the needle in too far and damage the underlying flight muscles. Fold a few feathers back the wrong way or pull a few feathers out to expose a bald area. The aim of inoculation is not to inject the vaccine but rather create a puncture in the skin that mixes the vaccine with both air and blood. Dip the supplied needle into the vaccine and push the tip of the needle at an angle through the skin so that a small ‘blood ooze’ is created. Withdraw the needle leaving a small bead of vaccine behind. The job is done. Most birds will develop a small vaccine reaction – a white thickened skin nodule that may or may not be covered by a scab in 7 to 14 days. This then heals over the following 2 to 4 weeks. The inoculated bird is infectious to other non-vaccinated pigeons while it has its nodule. After 2 to 4 weeks (up to 6 weeks after the original vaccination) the nodule heals. The bird is no longer infectious and the bird develops a lifelong immunity.

Is the vaccination harmful?
Absolutely not. Basically, there are two types of vaccines – live and killed. Live vaccines contain live viruses that deliberately infect the birds with a mild form of the disease. The live viruses in these live vaccines have been modified so that they are no longer able to cause disease. They do, however, stimulate the development of immunity not only to themselves but also to the nastier disease causing strains. Killed vaccines just contain killed virus. The birds cannot become infected with these viruses but their immune systems are still exposed and an immunity will form. As a general rule, the level of immunity formed is much higher and lasts much longer with live vaccines such as the pigeon pox vaccine currently in use in Australia.

How often should I vaccinate my birds?
A single vaccination confers life time immunity, so just once is enough.

What happens if I vaccinate a bird that has already been vaccinated?
No harm done. If immune birds are vaccinated again, all that will happen is that they will not react to the vaccine i.e. no thickened nodule or scab will form at the inoculation site. Because they are immune the modified live virus in the vaccine cannot infect them. If there is any doubt as to whether a bird has been vaccinated or not, it is safer to re-vaccinate the bird to make sure that it is immune.

How young can I vaccinate a pigeon?
The recommendation is that all pigeons should be over 6 weeks of age when inoculated. Often, however, much younger pigeons are vaccinated, even at 1-2 weeks of age in the nest without ill effect. As pigeons grow, their immune systems naturally become more and more mature and so they are better able to form a strong immunity to pox virus after vaccination. Also young growing pigeons are facing multiple stresses. Vaccinating with a live vaccine, although modified is another stress. All together these stresses have the potential to compromise the growing pigeons development. The usual advice is to wait until the youngsters are settled in the racing loft, eating and drinking properly and with their own perches. Usually by 6 weeks of age this has occurred. However in the face of an outbreak it is better to vaccinate young birds. If they are well otherwise and are being well cared for it is unlikely that this will do them any harm.

Can I loft fly or toss recently vaccinated birds?
Between 7-14 days after inoculation a reaction to the vaccine will develop at the inoculation site. This can vary from a very small thickening in the skin to a large raised nodule covered by a scab. This reaction develops as the bird is reacting to the vaccine and starting to form an immune response to it. Some birds develop a slight fever during this time. These birds will appear a bit fluffed and will be a bit less active in the loft. These birds may also drink a bit more and as a result develop watery droppings. This stage is transient and mild. Once the nodule has finished developing the birds are again well. Up to 7 days and after 14 days birds can be managed normally. Between 7-14 days there is no problem loft flying the birds but it is best not to toss them during this time. After vaccination manage the team of youngsters normally but just be mindful that between 7 and 14 days some might be feeling a bit ‘off’.

Can I race recently vaccinated birds?
No. Clubs and federations throughout Australia do not allow birds with obvious transmissible disease to be entered into races. Pigeons that are still carrying their scabs after inoculation are infectious to other pigeons (that have not been inoculated) and therefore should not be allowed entry.

I have heard that vaccinating birds can give them a boost and help to improve race results. Is this true?
To some extent yes. As pigeons pass the 14 day stage after inoculation and their reaction at the inoculation site starts to heal their immune systems are ‘switched on’ and in some birds there does appear to be a transient time where a short period of ‘super health’ is achieved. Some fanciers have done well during this time and have at least partially attributed their good results to this. This practice obviously however should be discouraged. Birds will react differently to the vaccine and while some birds may be very good others may react more slowly, have a slight fever and be a bit unwell. These birds will be at risk of being lost if raced. Hopefully vaccinated birds would be detected by handlers during race marking. There will always be fanciers, looking for an advantage, who inoculate in inconspicuous locations. Federations need to be vigilant against this.

Should I vaccinate birds that appear unwell?
Definitely not, for two reasons. Birds that are obviously unwell with one infection such as ‘eye colds’ will not form a good immunity to a second i.e. the virus in the pox vaccine. Also vaccination is another superimposed stress and can exacerbate preexistent health problems e.g. if a group of young pigeons are struggling to form immunity and recover from an outbreak of canker or ‘eye colds’ vaccinating them will only make this harder for them and will likely precipitate an outbreak of this problem.

If my birds become unwell after vaccination can I medicate them?
Yes, Pigeon Pox is a viral disease and the commonly used medications even antibiotics have no effect on it. If pigeons become unwell after vaccination the cause should be investigated and appropriate treatment given. In fact, the immunity they form will be better this way.

I vaccinated my birds and I cannot see any ‘takes’. Has the vaccine worked?
Maybe not. Birds should be checked 10-14 days after inoculation for ‘takes’ i.e. modular thickening with or without a scab at the inoculation site. Not every bird will necessarily have this but the vast majority should. Not having this arouses suspicion that the vaccine may not have worked. By far the most common cause of vaccine failure is that the vaccine has got warm and died prior to use. The vaccine is a living viral culture that is killed by heat and UV light. The vaccine should be stored in the freezer, reconstituted immediately prior to use and be kept cool and out of direct sunlight while being used. Prolonged exposure to heat and UV light gradually kills the virus in the vaccine meaning that more and more vaccine needs to be inserted at the inoculation site to provide sufficient live virus to form an immune response. Eventually all virus will die. There will be nothing for the pigeon to react against and no immunity will form. There is usually no problem with use or storage once the vaccine has reached the home loft but keeping the vaccine cool during transport and posting can be a problem because of the shipping distances involved and the hot weather of Australia. Having said that when compared to other viruses pox viruses are fairly tough and there are instances of vaccine not being refrigerated for several days (and even being reconstituted with boiling water) and still being ok. Every effort should be made to keep the vaccine cold.

Other causes of vaccine failure include poor vaccination technique or inoculating birds that have diseases that interfere with the functioning of the immune system. In particular, Circo virus infection is becoming more and more relevant here.

Is it ok to share my vaccine with other club members?
Absolutely not. This is a really silly activity that has become acceptable practice in some parts of Australia. There are many diseases in young pigeons that are spread through the blood – common ones include Circo virus, Chlamydia and Salmonella. If you are the last ‘cab off the rank’ in effect, you are inoculating birds with all the germs found in all the pigeons that have been previously inoculated with that batch of vaccine. Direct inoculation into the bloodstream is a really great way of introducing these diseases into your birds. For the sake of the cost of the vaccine, buy your own bottle of vaccine or if you must share, only share with a fancier who you know has no health problems in his birds.

Can I re-freeze and re-use the same vaccine?
This should not be a problem provided the vaccine has not been in full sun for an extended period or been allowed to get hot during use. A good trick is to pack a stubby holder with ice and have the vaccine sitting in the middle of this while inoculating the birds. If at the end you think that the vaccine is ok, re-cap the vaccine bottle and place it back in the freezer. It will then satisfactorily store. It’s always a drag to re-use a bottle in this way then find that it has not worked. For this reason it can be a good idea when re-using vaccine to initially just vaccinate 2 to 3 birds and check these ten days later. If they have taken, then you know the vaccine is still ok and you can then go ahead and vaccinate the rest of the team.

Is there any treatment for pigeons with pigeon pox?
No. There is no direct treatment for a pox virus. Sometimes however, where pox vesicles form inside the mouth, because of the warm wet environment here, they can become secondarily infected with bacteria and canker organisms. Sometimes these birds will benefit from a short course of anti-canker medication and an antibiotic. This will help to dry up the lesion and make the bird more comfortable while the virus runs its course. Lesions on the skin are best left alone. Attempting to remove them or treating with various topical agents tends to cause more tissue destruction and delay healing.