Cryptosporidium is a disease every keeper or snakes and lizards need to have some awareness of. I do not claim to be an expert on this organism, but I've learned some basic information that I think every keeper should know. I am creating this page hoping to raise awareness within the reptile community and I will update it as new information and corrections become available.
There are numerous species which can infect mammals and reptiles. The reptile varieties do not cause disease in mammals and the mammal varieties do not cause disease in reptiles. This means if your reptile is sick with Cryptosporidium it did not get it from a feeder mouse and if you're sick with Cryptosporidium you did not get it from a reptile. However, it does mean some forms of Cryptosporidium testing can induce a false positive of sorts. If a feeder rodent has Cryptosporidium parvum (a mammal form of Cryptosporidium sometimes found in rodents) that can be seen in your snakes stool and some forms of testing will show a positive result. The good news is testing is available that has overcome this problem and can identify Cryptosporidium down to the species level. This is the kind of testing that is required for reptiles. There are at least two species that cause disease in reptiles Cryptosporidium serpentis and Cryptosporidium varanii also sometimes refered to as Cryptosporidium saurophilum. Sometimes they are referred to as "Snake" and "lizard" cryptoporidium but this is not accurate and studies have demonstrated that snakes and lizards can be infected with either species. The two species cause slightly different forms of disease but from the hobbyists perspective what you really need to understand is that testing for only one of the two species is insufficient.
Since there is no effective treatment for the disease, the only solution is to reduce the possibility of spread. Should you be unlucky enough to find yourself treating an animal with this disease you will want to involve a veterinarian as soon as possible. Repurposed drugs have been tested and if given early enough may provide relief, but they are unlikely to cure the reptile and will likely to continue to intermittently shed oocysts and spread disease to other reptiles in your collection. Your veterinarian will provide you with the latest information on treatments and help you navigate the decisions ahead but understand that treatment options are likely limited and cures unlikely to exist. To make matters worse the oocysts are smaller than coccidia and resistant to most forms of disinfectation and are said to be able to last at least months in the environment and remain viable. Currently, the most accessible disinfectant is 6%+ or stronger hydrogen peroxide which needs to remain in place for 20 minutes. The standard drugstore variety is 3% and insufficient. Searching online for medical or food grade hydrogen peroxide should allow you to find 6% or 12% (the later can be diluted down to 6%). Note that this strength of peoxide will cause skin discomfort so wear gloves and if any potential for splashing exists goggles. It is thought that fungus gnats and phorid flies may be a vector for the spread of this disease. Snakes have tested positive when kept in the same room as infected snakes. While there is no way to be sure that cross contamination did not occur via some other method, it is wise to consider such insects a potential vector for the spread of this disease until proven otherwise. The flies seem dependent on moist surface such as damp mulch, soil, or feces in order to reproduce effectively in a reptile room so regular removal of any waste or moist surfaces is recommended where possible. The most effective tools we have against this disease are quarantine and screening. By quaranting new arrivals as far away from existing animals as possible you have the time to perform testing and reduce the odds that this disease will find its way into your collection. Animals in quarantine should always be serviced last and no tools, water bowls, etc should be shared between quarantined animals and established animals. Since we've already mentioned that flies may be a source of spreading this disease, it would be wise to keep quarantined animals exposed to as few flies as possible. Closed doors will slow the spread, noseeum insect tents would greatly help, or specialty tubs created with gasket boxes and noseeum/fruit fly proof ventilation screening would all be potential solutions to reduce the ability of flies to access the snakes in quarantine. For any new animal in my quarantine area, I immediately screen using a cryptoporidium panel as soon as the animal defecates (this covers both species important to lizards and snakes) from Research Associates (https://www.vetdna.com/test-type/reptiles). The panels barely cost more than an individual test of either species and because this is a feces test it can be sent via first class mail or USPS ground inexpensively in a bubble mailer. Before ordering any reptile, I suggest ordering a package of their swabs (you need to use their swabs not cotton ones) and obtaining some padded envelops. Should the animal test positive, I will arrange to immediately return it back to the seller. A false positive is highly unlikely because it is screening for dna of those species. However, a false negative is possible as animals may only intermittently shed oocysts. Several screenings are needed to ensure the animal is not carrying this disease. Additionally, I have seen individuals continue to list animals for sale even after I informed them they are sending out animals with this disease. Extreme caution is advised and assume every animal is positive until verified otherwise. This is not an uncommon disease in the reptile hobby it is just uncommonly recognized as the reason animals are passing away.
For symptoms there is a lot of misinformation online that cryptosporidium would be easily detected in a collection. Nothing could be further from the truth. Reptiles may have few or no symptoms yet still be intermittently producing oocysts and spreading disease in one's collection. Additionally, animals can seem fine then suddenly take a turn for the worse. Unfortunately, by the time disease is detected in an animal, it will often have spread to many other animals. Many of the same symptoms of cryptosporidium can have other causes. In general, animals that appear to be thin or wasting away despite eating or with a midbody swelling are especially suspicious but animals showing few if any symptoms are not uncommon. Should you have an animal pass away that you believe may be related to cryptosporidium you should contact your Veterinarian to determine if a necropsy can be performed. There are also online sources that can assist with necropsy. Fishhead labs is one such service. A verarinarian college may also be willing to assist you. You want to put the animal in a cold but not freezing fridge as soon as it is discovered to preserve it. If the animal cannot be shipped or delivered within 24 hours, you should contact the service you intend to use and ask for instructions. Preserving in 70% ethanol (available online or diluted everclear ) is another option which will preserve the speciman for a longer period of time.
There are numerous species which can infect mammals and reptiles. The reptile varieties do not cause disease in mammals and the mammal varieties do not cause disease in reptiles. This means if your reptile is sick with Cryptosporidium it did not get it from a feeder mouse and if you're sick with Cryptosporidium you did not get it from a reptile. However, it does mean some forms of Cryptosporidium testing can induce a false positive of sorts. If a feeder rodent has Cryptosporidium parvum (a mammal form of Cryptosporidium sometimes found in rodents) that can be seen in your snakes stool and some forms of testing will show a positive result. The good news is testing is available that has overcome this problem and can identify Cryptosporidium down to the species level. This is the kind of testing that is required for reptiles. There are at least two species that cause disease in reptiles Cryptosporidium serpentis and Cryptosporidium varanii also sometimes refered to as Cryptosporidium saurophilum. Sometimes they are referred to as "Snake" and "lizard" cryptoporidium but this is not accurate and studies have demonstrated that snakes and lizards can be infected with either species. The two species cause slightly different forms of disease but from the hobbyists perspective what you really need to understand is that testing for only one of the two species is insufficient.
Since there is no effective treatment for the disease, the only solution is to reduce the possibility of spread. Should you be unlucky enough to find yourself treating an animal with this disease you will want to involve a veterinarian as soon as possible. Repurposed drugs have been tested and if given early enough may provide relief, but they are unlikely to cure the reptile and will likely to continue to intermittently shed oocysts and spread disease to other reptiles in your collection. Your veterinarian will provide you with the latest information on treatments and help you navigate the decisions ahead but understand that treatment options are likely limited and cures unlikely to exist. To make matters worse the oocysts are smaller than coccidia and resistant to most forms of disinfectation and are said to be able to last at least months in the environment and remain viable. Currently, the most accessible disinfectant is 6%+ or stronger hydrogen peroxide which needs to remain in place for 20 minutes. The standard drugstore variety is 3% and insufficient. Searching online for medical or food grade hydrogen peroxide should allow you to find 6% or 12% (the later can be diluted down to 6%). Note that this strength of peoxide will cause skin discomfort so wear gloves and if any potential for splashing exists goggles. It is thought that fungus gnats and phorid flies may be a vector for the spread of this disease. Snakes have tested positive when kept in the same room as infected snakes. While there is no way to be sure that cross contamination did not occur via some other method, it is wise to consider such insects a potential vector for the spread of this disease until proven otherwise. The flies seem dependent on moist surface such as damp mulch, soil, or feces in order to reproduce effectively in a reptile room so regular removal of any waste or moist surfaces is recommended where possible. The most effective tools we have against this disease are quarantine and screening. By quaranting new arrivals as far away from existing animals as possible you have the time to perform testing and reduce the odds that this disease will find its way into your collection. Animals in quarantine should always be serviced last and no tools, water bowls, etc should be shared between quarantined animals and established animals. Since we've already mentioned that flies may be a source of spreading this disease, it would be wise to keep quarantined animals exposed to as few flies as possible. Closed doors will slow the spread, noseeum insect tents would greatly help, or specialty tubs created with gasket boxes and noseeum/fruit fly proof ventilation screening would all be potential solutions to reduce the ability of flies to access the snakes in quarantine. For any new animal in my quarantine area, I immediately screen using a cryptoporidium panel as soon as the animal defecates (this covers both species important to lizards and snakes) from Research Associates (https://www.vetdna.com/test-type/reptiles). The panels barely cost more than an individual test of either species and because this is a feces test it can be sent via first class mail or USPS ground inexpensively in a bubble mailer. Before ordering any reptile, I suggest ordering a package of their swabs (you need to use their swabs not cotton ones) and obtaining some padded envelops. Should the animal test positive, I will arrange to immediately return it back to the seller. A false positive is highly unlikely because it is screening for dna of those species. However, a false negative is possible as animals may only intermittently shed oocysts. Several screenings are needed to ensure the animal is not carrying this disease. Additionally, I have seen individuals continue to list animals for sale even after I informed them they are sending out animals with this disease. Extreme caution is advised and assume every animal is positive until verified otherwise. This is not an uncommon disease in the reptile hobby it is just uncommonly recognized as the reason animals are passing away.
For symptoms there is a lot of misinformation online that cryptosporidium would be easily detected in a collection. Nothing could be further from the truth. Reptiles may have few or no symptoms yet still be intermittently producing oocysts and spreading disease in one's collection. Additionally, animals can seem fine then suddenly take a turn for the worse. Unfortunately, by the time disease is detected in an animal, it will often have spread to many other animals. Many of the same symptoms of cryptosporidium can have other causes. In general, animals that appear to be thin or wasting away despite eating or with a midbody swelling are especially suspicious but animals showing few if any symptoms are not uncommon. Should you have an animal pass away that you believe may be related to cryptosporidium you should contact your Veterinarian to determine if a necropsy can be performed. There are also online sources that can assist with necropsy. Fishhead labs is one such service. A verarinarian college may also be willing to assist you. You want to put the animal in a cold but not freezing fridge as soon as it is discovered to preserve it. If the animal cannot be shipped or delivered within 24 hours, you should contact the service you intend to use and ask for instructions. Preserving in 70% ethanol (available online or diluted everclear ) is another option which will preserve the speciman for a longer period of time.