Viral papilloma is an infectious warty growth which, while found in other species, is most common in the lacertids – the skinks, cordylids and tegus being most commonly kept as pets. Because these animals are smooth skinned as a rule, these warts are quite easy to spot and most often occur on the head or neck, although they are sometimes found clustering around the mouth.
Signs to watch out for
Viral papillomas are rough, flattened growths appearing on your lizard’s skin, usually in groups but sometimes singly. They are caused when there is a minor viral inflammation locally which the body’s defences copes with by encasing it in a warty outgrowth. It was many years before they were identified as having a viral cause, as it was not possible to demonstrate it in the laboratory, but research finally found that there was a link and this has helped a little with treatment. Extreme cases can be helped by antivirals, but as they have been developed to treat human viruses their success is not guaranteed. The animal may well develop viral papilloma following a bite, often a mating bite, so previous behaviour is also a clue if you notice viral papillomas developing on your lizard. A further sign may well be an incomplete or difficult shed. Because the papillomas are more than one skin layer deep, they may prevent a clean shed and then the lizard can get infection at the site of retained or ripped skin, so it is important to get the animal to the vet.
Treating Viral Papilloma in Lizards
Antivirals are of dubious efficacy, so if the viral papilloma is causing mechanical problems, for example with shedding or if they are clustered round the mouth and are getting in the way of the lizard’s feeding, then they can be removed surgically. The problem with this is that it is difficult to dress surgical incisions on a lizard and so the site is then open to opportunistic infections by bacteria and fungi. As the lizard may well scratch or knock the papilloma, causing an open wound, it is probably advisable to treat with anyway antibiotics and antifungals to prevent such an infection. Because the only way to identify a virus is by electron-microscopy it is not really practicable to do this in a lizard, as the process is very expensive. It has been done in the research arena though, and the family of viruses which cause the warts has been identified and they are called – perhaps unsurprisingly – the papilloma viruses. They do not cause any other symptoms, such as the diarrhoea of the adenovirus family, but can nonetheless cause the lizard to feel generally unwell because of the secondary problems of irritation and infection at the site.
This condition really is one of those which cannot really be prevented, although vigilance by the owner can stop it getting out of hand. The papilloma virus warts can cause discomfort but if they are round the mouth they can give the lizards real trouble with eating and can therefore cause a general reduction in condition and this will leave the animal rather prone to other infections and possible vitamin deficiencies. The virus cannot be spread as such, in so far as it is not likely to be in a droplet in the air or similar, but they will be released if the wart is broken and it bleeds. Cleanliness is therefore important and if the owner notices that the papillomatous wart is bleeding or crusting, it should be cleaned with an antiseptic wipe as often as is practical. The best way to help the lizard beat one outbreak and not have another is to keep it in the peak of condition by paying special attention to its habitat and diet, making sure that the temperature is just so and that it is getting enough vitamins.
How do outbreaks happen?
In the case of any viral infection or condition, sometimes there is no telling how an outbreak can have begun. If a new lizard is introduced then this is obviously the first thing to consider, but the odd thing about viruses is that they can lie dormant in the body of the host and cause no symptoms for years after the primary infection. They then can break out when the host is ill or just in less than perfect health. An excellent example to explain this is the human herpes ‘cold sore’ virus, which is always present in the body, only breaking out when the person is ill with a cold and the skin is damp or broken because of the nasal discharge of a respiratory tract infection. This is the case with papilloma virus as well, so the new lizard might not be the cause in the first instance, although of course the introduction of a new animal may have stressed the now affected animal, giving the virus the chance to beat the immune system and cause the warty growths.
Viruses are not bacteria or fungi as many people think; in fact, many authorities debate whether viruses are living cells at all, as they have no cytoplasm or anything else in common with living things except DNA. Different viruses can live for different lengths of time outside of their hosts but they cannot replicate anywhere except inside a cell. This means that although the papilloma virus may be shed from the wart it will not be able to increase in numbers except if it is picked up by another lizard.