| Deformity in snail shell due to unknown cause, looks very similar to that caused by calcium deficiency although this snail had access to a constant supply of calcium. Note the rough area and the grey patch. This part of the shell is more brittle than the healthy areas. (Achatina smithii) |
|
Snail Diseases, Injuries and Mutations
The illnesses of snails is something that nobody seems to know all that much about. What I am gradually putting together on this page are the problems I have experienced with my own snails and the cures and remedies (if any) that I have used.
Scroll down to reach each disease. As this page gets bigger I will probably make it easier to use by providing links to the relevant sections, but as yet it is still a work in progress.
To add to the information here or to discuss what I have written please feel free to contact me. Please type "snail disease" in the subject line and I will respond as soon as I am able.
Broken or Damaged shell:
There are several ways in which a snail's shell can be said to be broken. If the shell is chipped or uneven-looking around the rim it is nothing to worry about. The snail can repair this in its normal course of growth. New shell is created as the snail deposits the necessary materials at the shell rim, and any chips and breaks at the rim are therefore healed as and when the snail next grows. Often wild-caught snails arrive with the shell in a badly chipped state, and it takes them some time to settle down and begin to re-establish growth patterns. However it is nothing to worry about if your snail takes a long time to repair chips in the shell-rim, and in fact it would not be harmful to the snail at all even if the chipped rim were never to heal.
A small dent to any area of the shell should not be considered a problem, although if it is in the second coil from the tip the ovo-testes might be damaged and the snail's reproductive ability may therefore be affected.
A break to the shell can be harmful if is further up the shell. Holes or cracks in the shell away from the growing rim must be taken very seriously. If the snail suffers a cracked shell due to being dropped or falling onto a hard surface it is likely that it will survive, if given the right conditions. It is important that a snail with such an injury is NOT handled, except to replace it in the tank. Food and cuttlebone must be made readily available and the snail must be misted with clean water more regularly as there is a risk of the snail losing moisture through the crack and therefore becoming dehydrated. If the tank is particularly over-crowded or is in need of cleaning out it may be more beneficial to the injured snail to be placed instead in a seperate container with clean, fresh substrate. This minimises the risk of other snails disturbing the shell and potentially making the injury worse, and minimises the risk of infection getting into the site of the injury. Left to its own devices the crack may well heal sufficiently that it will not be a problem for the snail, although once a snail has suffered this type of injury it must be remembered that the shell will not be as strong or tough and further potential injury should be avoided at all costs.
A hole in the shell is potentially fatal as snails are not usually able to fully heal the wound site. The advice is as above but it is important to recognise that the snail may well deteriorate and die. With a hole in the shell it is even more important to keep the snail moist as fluid will be lost very quickly through the wound site and the snail will be very dehydrated. In some cases the snail manages to repair the hole with a thin papery covering rather like the one used to seal the snail into the shell during times of hibernation or aestivation. This prevents fliud loss and infection but the snail remains vulnerable because there is a permanent weakness in the shell at that point and the slightest pressure or bump can reopen the hole.
It might be possible to repair a hole in the snail's shell using egg-shell or a similar substance. It has been tried on one snail that I know of. A piece of clean eggshell that was larger than the hole was glued onto the snail's shell using small amounts of nail glue, which is quick drying and strong. This prevented moisture loss and for a short time the snail appeared to be doing very well, but died a couple of months later. If trying something like this it is essential that no glue enters the hole itself and that the snail is closely supervised while the glue dries to prevent any glue getting onto the snail's body. Only a very small amount of glue should be used. Since this is not well-researched I cannot simply reccommend that this procedure should be undertaken, however it does seem to have the potential to aid in recovery after severe injury to the shell. An alternative would be to find a vet that specialises in birds and persuade him/her to use a beak-repair kit to mend the hole in the shell.
It is also possible that a snail's shell might be damaged because of the snail's genetic makeup and/or a calcium deficiency. I have seen an Achatina smithii with what looks like damage due to calcium deficiency on parts of the shell, despite the fact that it was kept in a tank with plenty of calcium and was the only snail in the tank to suffer any deformity. One part of the shell looks brittle, is partly white in colour, and is highly textured with ridges and dents. I suspect that the snail suffered either an illness or a genetic problem which prevented it from utilising the calcium in its diet correctly. However the shell growth became normal again after a while and the snail seems to suffer no ill effects.
The shell of a snail that is suffering from a calcium deficiency will usually become either soft or brittle, with many ridges as a result of poor and sporadic growth. It most often appears as white in these circumstances as the top layer of the shell fails to correctly develop. In most cases a shell defomration like this is due to a lack of calcium in the diet and can be remedied by introducing a constant supply of cuttlebone. However, as mentioned above, it does sometimes seem to happen spontaneously, either in part or all over the shell. In tank conditions it should not be a life-threatening problem although extra care should be taken to handle the snail very gently to avoid injury as the shell is likely to be less robust than that of a healthy snail. Below is a picture of Achatina smithii showing shell deformity or damage for unknown reasons, probably linked to the snail being unable to process calcium correctly.
Expelled Digestive Tract:
This is a fairly uncommon sighting in snails I believe, yet it happened to two of my snails in fairly quick sucession. The first snail expelled it's entire digestive tract inside out through it's mouth, breaking it's radula into several bits at the same time. It survived for 2 days after this, though because it was unable to retract the gut aI took the decision to put it to sleep.
The second snail did the same thing two weeks later, but the gut was not entirely expelled, and the radula was not broken. This one died a matter of hours after the expulsion of the gut occurred, and rigor mortis had set in by the fourth hour.
Of the first snail I have no records of ill health but the second had been ill for some time and these are the symptoms I noticed in her in the 6 months leading up to the gut expulsion and her death:
- loss of appetite
- cessation of shell growth
- Increased damage to existing shell (no shell repair)
- Increased periods of inactivity, leading up to almost total inactivity in the weeks before death.
- change in the appearance of the mouth and radula. See diagram below. (please excuse my poor attempt at drawing!)
I am not sure how important this difference in the mouth of the snail is, althouth it was a clear indication in the case of the second snail that something was wrong. I believe the illness could have been due to a parasitic invasion of some sort or possibly due to a genetic defect in these two snails (which were desended from the same parents). Please note that this is only a hypothesis. Another possibility is that the snails had tumours or other growths causing illness and gut expulsion. As I do not have the equimpent necessary for post mortem I do not have any way of discovering if this is the case.
This is certainly one of the more disturbing afflictions I have seen in any snail. The gut hanging from the mouth is not a pretty sight and it is clear that the snail is in incredible discomfort. It takes a lot of willpower to pick the affected creature up to examine or move it. I would have to recommend that when this occurrs the only humane course of action is to have the snail put to sleep.
I have heard of a few cases where at first the snail was able to retract the expelled gut and carry on as normal, but in all cases the expulsion occurred again, and no snail that I know of has ever recovered from this. Therefore euthanasia seems to be the correct course even if the snail has recovered once before from the same affliction.
Death from Malnutrition:
By this I do not mean death caused by underfeeding. Rather I mean that the snail simply refused to eat, lost weight and died. I have seen this happen three times, each time in a juvenile snail which was also below average size. The snail would attempt to estivate a lot, and would be inactive for long periods. It would eat only a small amount of food when coaxed. Gradually the body changed colour, darkening to an almost black grey, and the snail felt lighter and lighter in weight. When retracted into the shell the snail would go a long way in instead of just as far as the rim of the shell. Untreated, the snail was eventually found shrunken into the shell and beginning to decay.
I have found that if detected early this can be treated, though I am not sure about cured, as the snails that have had this problem have all died at a fairly young age. Treatments I have used include a lukewarm bath every day to encourage the snail to move about, and feeding the snail with baby food or pureed fruit and vegetable, with calcium powder sprinkled into it. Keeping the snail slightly warmer and moister than usual also seemed to help, but when the treatments were discontinued the snail quickly lost condition again and as mentioned above, died.
My theory is that the process of natural selection has a part in this. In each batch of eggs there are many baby snails and some are strong. There are also some very weak ones, and I believe that it is these snails which so mysteriously "lose the will to live" at a young age. As yet I do not know of any guaranteed cure.
Death after overfeeding on pasta
This has sadly happened to two of my snails and I have heard accounts of it happening to others as well. I can hereby reccommend that you *do not feed pasta to your snails*. It may be ok in a very small quantity, but in my opinion not worth the risk. I gave them a plate of cooked pasta (cooled of course) and left them to eat. All four seemed very keen on it and so I left them to it until they had all finally left the plate alone, when I removed the leftovers, which were about half the original quantity. I noticed a few hours later the snails were beginning to look very lethargic. I decided they must be very full, and left them in peace overnight. The next morning two in particular seemed to be in far worse condition. They were sitting on top of the substrate with their bodies fully extended, eyestalks retracted, - they looked much like an asphyxiated snail does, - and were not keen to move at all, even when encouraged. I realised then that I had made a mistake in giving them so much pasta. I left them well alone, with no food, and well-misted. I re-misted every few hours to make sure they had enough moisture. While two snails recovered, one to complete fitness and one to the stage wher I know it would be ok, the two that were sicker got worse. I noted they had not moved all day, and had not excreted at all either. I left them untouched but with plenty of water overnight. The next morning both were dead, - the smaller one had retracted right into it's shell, but the large fulicia had literally exploded out of the shell. Not only was it's body filled with fluid, giving it a really bloated appearance, but it had pushed it's body from the shell, - as if to make new shell growth but on a massive scale. Instead of a millimetre rim of body where the area of new growth was, which I would expect, especially when the snail has over-eaten, there was an area of body showing that was a good 3 centimetres at it's widest part. Obviously the snail had been unable to digest the pasta, especially in such a large quantity, and his body had undergone some violent reaction causing swelling, fluid retention and death. Pasta swells if you place it in fluid, even when it is essentially cooked, and it seems that the snail had eaten too much and then had it expand even more inside the digestive system. Sadly this was the mutated fulica with eight rings (see genetic mutations below) and so I lost something unusual. The other snail to die was Achatina immaculata, again sadly a fairly uncommon snail.
Cures: Well the best cure is prevention, so learn from my mistake and do not feed your snail pasta. If however it is too late for that advice, or you see similar symptoms when giving other "stodgy" foods, I recommend removing all food from the tank, keeping the snails well misted, and leaving them to rest. One of the snails that survived took several days to recover back to his full health, - so patience is important, and also make sure you don't feed the snail anything but iceberg lettuce (which would help to flush out the system) until you are sure it is feeling better (a sign of this would be if it has excreted any of the remains of the pasta)
Below is a picture of the snail that died, taken shortly after death. It is not a nice picture so don't look if you are squeamish.
Note:
- the protruding inner body, and the extended body, swollen and distorted into a rather odd shape. Fluid and mucus can also be seen escaping from what was the breathing aperture under the nearside of the shell.
- the unusual shell shape (relevant to the section on genetic mutation below). It is thinner and more streamlined than the normal fulicia shell, and has eight and a half coils as opposed to the usual seven and a half.
Mutation caused by overcrowding: (Non-Genetic Mutation)
Snails are rather like goldfish in that they tend to grow to fill the space available. Of course, they reach a peak at which they will cease to grow no matter what size tank they are in, but if kept in a tank that is too small they will end up smaller than they could have been and may suffer some deformity in shape and shell texture as a result.
I am ashamed to say that I have seen this happen in my own snails. I had two Achatina fulica which were only 5cm long and had rounded shells not dissimilar in shape to those of the aquatic apple snail. Their shells are also very rough and ribbed and are in parts grey in colour. I believe their condition to result from them being kept in an overcrowded tank for the first two years of their life. As newly-hatched babies they were put in with two adult snails in a small-ish tank. At the time I had no choice as I had no room for a larger tank and no-one willing to take on the baby snails (which had hatched by accident as I had missed the eggs and therefore not removed and destroyed them). They grew very slowly indeed, so that after two years they were still the size of 1 month old babies. Removing them to a larger tank caused them to grow considerably, but they retained their unusual shape and stayed significantly smaller than other snails of the same species. However this did not seem to affect them. They ate, slept, and so on just like any other snail, and also were perfectly able to produce viable eggs. One of them was perhaps a little younger than the average fulica when it died, but the other seems to be enjoying a normal lifespan.
Despite the fact that deformity caused by overcrowding seems to have no lasting damage when the situation is rectified, I would strongly advise that you make sure you have adequete tank space for your snails. In baby snails I am aware that overcrowding leades to a significantly lower survival rate, and snails that are permanently overcrowded will have shorter lives and be more prone to disease.
Genetic Mutation:
This is mutation that occurs naturally and not due to error on the part of the snail keeper. The most significant differences between snails of the same species I have noticed is that some grow far larger than others, when all are kept in exactly the same way. However a more interesting mutation is that of an extra coil to the shell. I had an Achatina fulica with an extra coil. His shell was also very pointed, thin and streamlined looking. He had eight and a half coils as opposed to the seven and a half of all my other fulicia snail. Interestingly he was still growing fast, and showing no signs of developing a proper shell lip, and looked set to grow yet another entire coil. Unfortunatly he befell a rather untimely death, see the pasta incident above.
Another very interesting mutation that can very occasionally be found in snails is that of albinoism. It usually affects only the body of the snail, meaning that the snail has a completely white body. This is especially striking in species such as Achatina fulica where the shell colour is dark and the body is usually also dark. This mutation actually ocurrs when the snail's genetic makeup lacks the correct information for pigmentation of the flesh. It is therefore dechnically a defect, although seems not to hamper the snails in any way. I have heard of a very few occasions when it was found that an albino snail is less strong and more prone to illness but in general it makes for an interesting, non-harmful variation. It is highly unlikely to occurr however, and therefore a very rare sight, especially in the U.K. Albinoism is a recessive genetic trait, and so if you do come across an albino snail it is possible to breed for the trait by breeding the albino with a normal snail and then breeding the offspring of the albino back with the albino again. The 2nd generation offspring stand a chance of being albino themselves and then once you have two albinos it is simply a matter of breeding them together.
Mutation is obviously out of the control of the snail-keeper. It is a genetic variation. However it is possible to breed for a specific kind of variation, as described above, and then only keeping and breeding the offspring which also show the same kind of tendency. This is an avenue I would love to explore further, although at present I do not have any snails with mutations to experiment with!
|
