Whether you have aviary birds, pet birds or wild birds, you should familiarise yourself with the perils of pox! So how important is pox virus to bird health?
Birds with avian pox will present in different ways, depending on the type of pox infection. What vets call “wet pox” is when the upper respiratory tract and lining of the gastrointestinal tract get attacked by the virus. The bird can have nasty internal lesions right down its throat, stomach or even further down. These birds would present with weight loss, difficulty breathing (blockage of the windpipe), difficulty eating, weakness or death.
“Dry” pox is much more obvious – there are wart-like growths anywhere on un-feathered skin – so around the eyes, on the beak or on the legs or feet. Sometimes the lesions can look like nasty tumours, other times they just look like a small lump or scab. The only real way to get a diagnosis is to take some of the affected tissue. Usually a vet would need to take a biopsy, but you might have a small amount fall off when cleaning or examining the bird that could suffice. It should be sent to a
lab for histological examination or PCR testing. The tissue should be sent in 10% formalin if possible, but ethanol may work if you are out in the field with nothing else available. Another excellent way to help is to take a photo – I have had several photos sent to me over the years and it can actually be quite easy to assess things from a photograph, and in some cases give a recommendation.
For the super academic people out there I refer you to the wonderful thesis by Hye Jeong Ha – found here which gives some in-depth background into this viral problem of birds.
The good news is that if it is a dry pox, the bird should heal up and form an immunity within weeks to months, and once they are immune, they are immune for life! The bad news is that this virus is easily spread – whether bird to bird (e.g. those sharing the same space), by fomites (unclean equipment) or by biting insects. It can spread more easily in warm, wet weather which is favourable for insects. Outbreaks spread by introduced bird species or new vectors e.g. mosquitoes can be detrimental to native species that have not encountered this disease before. Declines of native species have been attributed to pox in several countries, including Hawaii and possibly New Zealand.
Ideally, you should ISOLATE any bird with suspicious lesions away from other birds until it has overcome the infection. If you have a bird in rehabilitation it is advised you have it in a separate room, with separate equipment and feeding bowls. It is always good practice to treat these birds last. Treatment of external pox may simply involve cleaning and applying iodine if needed, or just leave the lumps for the birds to resolve naturally. I would not attempt to remove pox lumps unless they were a real problem, as there is more chance of bleeding or infection. Make sure you wash your hands and equipment after touching a suspicious looking lump. If wet pox, the bird will need veterinary treatment (fluids, feeding, warmth, antibiotics) if it has a chance to survive. If you have an outbreak, you need to consider insect control or barriers for your birds. There is a vaccine available, developed for the poultry industry and can be used in some species such as pigeons, chickens and turkeys. The effectiveness or safety of the existing vaccines is not yet known for many other species such as song birds but it has shown promise in some trials.
Lastly, although this virus is well known, its exact distribution is unknown and there may be new species affected or viral strains with high mortality. So, if in doubt, it is good to report cases or outbreaks to a wildlife veterinarian, wildlife agency or biosecurity agency in your country or region.
Dr Janelle Ward Wildlife Veterinarian
(All photos are the copyright of Wild Bird Care - NZ)
Learn Bird Care was co-founded by Dr Janelle Ward and Mandy Robertson. Learn Bird Care offer specialist online courses on wild bird rescue,1st aid and care.
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