Cryptosporidium in lizards


Cryptosporidium is a gastrointestinal parasite which can infest many animals across a broad spectrum from humans to birds, via cattle, sheep and domestic pets, including reptiles. Although infections in any particular species tends to be by one species of cryptosporidium – for example, the main causative organism in humans and cattle is cryptosporidium parvum, but they can be affected by others. This is why hygiene is so important. 

Cryptosporidium is easy to catch – and here’s why

The life cycle of cryptosporidium is the same, whether it takes place in a lizard, a sheep or a person. The cryptosporidium is a protozoa, which is essentially a single cell which in this case is smaller than a human blood cell, although some protozoans are bigger. It can’t live outside its host, so when it is ready to breed – and that is a process so complex we won’t go into it here – it forms what is called an oocyst (which means a bag of eggs) and this is passed in the faeces. In this form it can live quite happily outside the body and in fact is resistant to almost all normal cleaning agents, including bleach. This oocyst contains four sporozoites, which can move about on their own and develop in the next gut they meet with and so the cycle continues. It is not known for sure how many – or perhaps we should say how few – oocysts need to be swallowed for the unfortunate lizard, person, bird or whatever to develop a cryptosporidium infection, but some authorities put it as low as one. Imagine how easy it would be to inadvertently swallow a single item as small as a red blood cell. Now you see why cryptosporidium is so easy to catch. 

Passing from lizard to lizard

Cryptosporidium spores (another name for the oocyst) are passed in the faeces of an affected lizard and can then survive almost indefinitely outside its body. In a single bowel movement – which will be loose and profuse (see later) – many hundreds of these spores will be shed, so the likelihood of another lizard ingesting the single spore considered a risk is huge. This is why it is essential to isolate any animal which you suspect has a cryptosporidium infection and clean the environment thoroughly with ammonia or caustic soda. Unless the habitat is extremely expensive, it may be better to destroy it and start again. Although it is potentially very serious, cryptosporidium begins by showing symptoms common to many lizard ailments and only later is cryptosporidium suspected, by which time the lizard is really ill.

Signs to watch out for

A later sign of cryptosporidium is a profuse and usually watery, always foul smelling diarrhoea, but early signs are lethargy and lack of appetite. Some lizards can carry cryptosporidium for years with no symptoms, but can suddenly become very ill with it, very quickly. This is often because of stress or another underlying disease which weakens the animal but just as often it comes on for no reason at all. Before the diarrhoea starts, the animal will probably have lost a lot of weight, very quickly. It will also have a tendency to become dehydrated and as with all cases of dehydration it is important that fluids are offered and if necessary forced to prevent organ damage. In some lizards with thin, pale skins (such as geckos, which are prone to cryptosporidium) the liver, which becomes darkened as a side effect can be seen under the skin as a blue mark not unlike a bruise. In other species, the whole midsection of the animal can become very bloated and tender.

Prevention of cryptosporidium

Three ways of preventing cryptosporidium are hygiene, hygiene and hygiene. Although the parasite is very difficult to kill outside the host, a thorough washing regime does minimise infection, cross infection and re-infection very successfully. Habitats should be kept clean and dry, and the lizards should be checked regularly to make sure they are in peak condition, as a healthy animal is much less likely to fall foul of a parasite infestation. When cleaning out the habitat, it is probably a good idea to wear gloves; don’t forget, cryptosporidium likes people too! It is probably a good practice not to let other people handle your lizards. They may be carrying an infection on their hands, especially if they are other lizard enthusiasts. If they are new to lizards they may not have the parasite under their nails, but on the other hand they probably will be a little clumsy at first with the lizard and may stress it and a stressed lizard is one which is disadvantaged when it comes to fighting off cryptosporidium.

But where does it come from?

Like so many other things that cause trouble in pets (and people) cryptosporidium can be found in many places from where it can happily get into a host. These include water, milk, undercooked meat and of course raw meat, the diet of some lizards. Even vegetarians are not without risk factors; if someone handles meat with cryptosporidium oocysts on it and then handles fruit or vegetables without washing their hands, the oocysts will survive easily on the surface and wait to be eaten, when the life cycle can start all over again.

Treatment of cryptosporidium

It may seem like a cliché but time is the only cure. There is no effective medication against cryptosporidium and it is a matter of waiting until the current infection burns itself out or the sufferer forms enough antibodies to repel the parasite. During this time, the lizard is probably not eating and drinking and tempting it to do both is the difficult job facing the owner. Once the animal recovers from the bout of cryptosporidium it is important to have its faeces checked to make sure it is not still shedding the spores and until it is clear it should not be put back with other lizards.


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