Shell rot is not a disease in itself, but is a term which covers any kind of problem with the shell of either a turtle or a tortoise. Symptoms are basically the same, whether the shell rot is caused by an injury or an underlying condition, and should be looked out for on a very regular basis. Most chelonian keepers will be aware that careful monitoring of shell condition is vital for the health of the animal, and any changes in the look of the shell, or the behaviour of the turtle or tortoise should be investigated straight away.
Causes of shell rot
Essentially, shell rot occurs when a bacterium or fungus or even usually in the case of turtles algae gets into the shell and causes an infection. This can happen in a number of ways and the most common is an injury, either caused by a fight or other aggressive behaviour. If the affected animal is kept with others, it is very important to make sure that it is not being targeted by one of its cage-mates. This can be quite covert, so it is worth watching quietly for a while if you suspect it is happening. Isolation of the aggressor is a good idea, as it will give the injured animal time to recover.
The injury may come from rough walls or flooring in the habitat and this is easily prevented by examining the inside of any cages or runs on a regular basis. It is important that all chelonians are kept in appropriate humidity if it is too dry, the shell will crack, allowing bacteria and fungi spores in to the break. If it is too damp, the shell can become soft and the plates may lift, again allowing disease causing organisms in. Ticks can also create the tiny break in the shell that is all that is needed to cause a bad case of shell rot. It is also not unknown for tortoises to be affected by insect attack whilst hibernating it is important to make sure that the hibernation conditions are such that will prevent this happening.
What to look out for
The first signs of shell rot are happily quite obvious and the owner should spot it very quickly. This is important, because shell rot is very contagious through a population and quite hard to eradicate. The shell will look uneven and plates may lift; there will possibly be an unpleasant discharge under the shell, which will smell horrible. There will be pitting of the shell and in extreme cases, parts of the shell may fall off, showing the bone underneath which may be healthy but may also be necrotic if the condition has been present for a long time. If the infection has reached the bone this is very serious and requires an immediate visit to the vet. As long as the shell rot is found quickly, it can be treated by the owner but no one should home medicate for longer than a week; if the condition persists or does not show improvement quite quickly, the vet should be called.
Treatment of shell rot in turtles and tortoises
There is a slight variation in the care given to turtles as opposed to tortoises, because of their different habitats. The best first step is to gently remove the affected tissue, which can be brushed with a toothbrush which can also be used to administer chlorhexedine or anything similar which your vet can recommend, which should eradicate the infection. Because the turtles shell is usually thinner than that of a tortoise, more care must be given when debriding the affected shell, as it is important not to reach the bone. Also it is more difficult to keep the area clean on a turtle, so it must be housed separately from its usual companions in scrupulously clean water.
Most organisms which cause shell rot thrive in an atmosphere with little or no oxygen, so it is vital to keep the area well aired. If it has to be covered for some reason, it should just be with a very light dressing of gauze to let the air in. The important thing to remember when treating shell rot in a turtle or a tortoise is to not persevere for too long on your own if there is not a very significant improvement within a few days or the animal seems to be failing then it must be taken to the vet as soon as possible.
Prevention is better than cure
Stopping a tortoise or turtle from developing shell rot is relatively easy. Aggression can be minimised by not mixing species and if you must mix for some reason, keeping relatively same sized animals together can make bad bites and clawing uncommon.
Keeping all habitats scrupulously clean is an obvious piece of advice but is surprisingly hard to do. Old bits of food can rot down in unnoticed places and can harbour fungi and bacteria, not to mention flies which will lay their eggs in any wound (fly strike), making any shell rot much worse. For aquatic species, it is very important to keep the water clean, as algae are also implicated in shell rot and dirty water constantly seeping into a break in the shell will almost certainly cause lots of problems. All keepers of animals should check them regularly and this will always be the best advice of all for preventing or at least minimising the severity of any condition know your animal and act fast if there is a problem.
How serious is shell rot and what can happen?
As long as it is caught early, shell rot is not too serious. It can be treated very successfully at home and although it can take a while to clear up, in an animal which may easily live for eighty years in the case of a tortoise, or forty for a turtle, a few weeks being nursed through shell rot is not such a big deal. The problems start if the shell rot has can penetrated deeper than the shell. This can then become necrotic or cause an abscess so deep seated that only surgical intervention can cure it and this can sometimes quite literally take years. Finally, if the turtle or tortoise develops septicaemic cutaneous ulcerative disease SCUD which is essentially a septicaemia arising from shell rot, then the outcome can be very serious indeed, with many vets advising euthanasia of the animal.