Cryptosporidium serpentis/varanii
“Crypto”
The deadly and highly contagious protozoa (disease) that no one wants to talk about:
(Disclaimer: Always consult your veterinarian) We update this page often as we obtain and learn new information so please check back and re-read)
Separating fact and fiction
Myths:
1. If I buy my animal from a reputable breeder my snake wont have crypto and I don’t have to worry about it.
2. If I quarantine 3-6 months and my new snake appears healthy I can safely bring it into my collection.
3. If I keep my snakes enclosure clean and sanitize my hands in between touching animals I won’t spread crypto.
4. If I use F10, clorahexadine, bleach or alcohol I will adequately clean things and it will kill the crypto and it wont spread.
The sad truth is that none of the above statements are true.
- Many breeders either dont know enough, or maybe care enough, and can unknowingly or unwittingly (or eek even knowingly) sell a snake with crypto. Many/most dont test and dont use adequate PPE/quarentining. Some breeders/hobbiests even assert that crypto is found in all collections, and so it should not be a big deal, and that if an animal is asymptomatic that it is “fine”.
- Crypto can in some snakes lie dormant for many years within a snake’s GI tract (usually stomach, sometimes intestines). MUCH of the time an animal is a-symptomatic (does not have any outward symptoms). None of our crypto positive snakes were symptomatic. NONE. However, some snakes do have symptoms which can include: regurgitation, either hunger or pickiness, and swollen abdomen among others.
- Crypto oocytes can attach to clothing, shoes, skin and any other surface and easily be passed around. Whenever a snake that is positive, defecates (poops) millions to billions of spores. It only takes a few spores to infect a new host.
- There is a lot of misinformation out there about how to “kill” crypto and how to deal with an outbreak. None of the usual cleaning methods are effective against crypto. (for example) Freezing does NOT destroy crypto.
Quick biology background on crypto which can help understand why diagnosing it is so hard:
Cryptosporidium is a genus and there are different species. Some are harmful to mammals and others to reptiles. What is harmful to snakes are two species:
Cryptosporidium serpentis (affects mainly snakes) and Cryptosporidium varanii (affects mainly lizards). Crypto serpentis mainly affects the stomach and it’s lining. Crypto varanii mainly affects the small intestine and sometimes the colon or large intestine.
Crypto varanii can be contracted by snakes as well and is just as lethal, so the issue that it lives in the lower gi tract causes some challenges when it comes to finding out if your snake has crypto via a gastric (stomach) biopsy. If it happens to have the varanii version the biopsy may not pick it up. UGH
The other challenge is that crypto is “shed” intermittently. So it is not always detectable in the stool samples. Cryptosporidium serpentis is more difficult to catch in a fecal sample, whereas Cryptosporidium varanii is easier. This is because of what part of the body each species prefers to colonize. (serpentis=stomatch, varanii=intestines)
The ways to diagnose C serpentis are from best to worst are: gastric biopsy, followed by a gastric lavage/swab, endoscopy/regurgitation swab/fecal swab. Gastric biopsy is the most accurate for serpentis, but your animal also needs to be 75 g or larger and not all vets perform this procedure. However if you snake has varanii the best way to detect it would be a fecal swab. Fecal samples are notorious for coming back with false negatives due to intermittent shedding of oocytes and a variety of other reasons.
A snake can also be a carrier and live for many years without any outward signs, silently infecting and spreading the disease. It is known that likely the young and stressed/immune compromised become symptomatic faster, It is not known how or why some snakes are carriers and why they may be more resistant to an outbreak.
Best Practice to help you try and avoid a Crypto outbreak:
- Ask before you buy: 1. Does the breeder test for crypto. 2. How do they test, 3. how often and 4. who do they test. 5. How and for how long do they quarantine? 6. Look at the photos the breeder is posting. Are they wearing gloves? 7. Are the snakes being photographed on a surface that can be sterilized (ie smooth non porous surface or in a gloved hand)? 8. If you are at a reptile show is the breeder or seller allowing anyone to hold the snakes with bare hands? Remember, hand sanitizer does nothing to reduce the spread of crypto.
Decide if it is worth the cost emotionally and literally if the answer to these questions is not clear or inadequate. In our experience many to most (but happily not all) breeders don’t bother with testing nor quarantining adequately, and those who have tested and quarantine, do so inadequately.
What we recommend:
- Test at least 25% of the established snakes in your collection every 1-3 months for minimum of 12 to 24 months (at least 7 fecal samples per snake) before considering them crypto free. If it is feasible to test your entire collection we would recommend that.
- Keep all new animals in a quarantine (separate rack preferably separate room or at least on the other side of a room from your collection) until 9-24 months or 7 monthly negative tests (depending upon your comfort level). We keep our animals in “permanent” quarantine and breeder/baby groups. We do not share anything between the “groups”.
- Do not handle your snakes with bare hands until you are positive that they are crypto free (see above) and use disposable gloves between all animals and when touching their containers/enclosures. Consider changing clothes and shoes between quarantine and your established clean collection. Assume every animal is infected until cleared. (see below for guidelines on considering your animal “clear”.
- When cleaning/feeding/changing waters etc always start with the “cleanest” and work toward the “dirtiest”. ie start with your hatchlings and move to quarantined ones last at the end of the day. Go shower, remove clothes and throw in hamper. Return to the reptiles the following day.
- Never cross feed a rejected prey food to another snake or put a rejected prey item back in the freezer with other feeders. Throw it away.
- Do not share things like tupperware/hides/waterdishes/tubs/enrichment/tongs. Each snake should have it’s own unless you can properly clean it in between animals. (see cleaning section). Ideally all items like enrichment and disposed of and never travel between snakes.
- Any clothes that you wear into your quarantine room, to a reptile store, friend’s house with reptiles, or a reptile expo should be removed and washed in a washing machine and dryer that have a steam sanitize/allergy setting and then wash your hands well for 30-60 seconds with soap and water. (See cleaning section)
- With PCR testing: test any new snake monthly for 3-6 months, then every 3 months for the first 18-24 months (longer is better) before accepting them into your collection. Yes MINIMUM 18 months of testing but honestly 36 months is better. and permanent quarantine is best. If doing a gastric lavage at your vet one to two lavages should be enough to clear your animal. A gastric biopsy is the most accurate of all the tests for cryptosporidium serpentis. Not all vets will do them and your animal needs to be around 75 grams or larger for that test.
TESTING for Crypto:
There are different ways to find crypto, none of which are foolproof. Crypto is very good at being cryptic. You can have an acid fast stain done at your vet or do it at home from a fecal or regurg swab and see if there are visible crypto oocytes on the slide. However this does not tell you which species of crypto might be present.
Rapid antigen tests (like Covid tests) are the least accurate of all the tests (home test kits) and cost about the same as a PCR test. Since an antigen tests only tests for the presence of any crypto genus it can give a positive if the mouse the animal is consuming has a “mouse crypto” that is not harmful to reptiles. So for accurate testing it is best to use PCR instead of antigen testing.
One or two time PCR/fecal testing is not adequate to rule out crypto. Crytpo can lie dormant and or shed intermittently for extended periods of time. So a “false” negative (where Crypto is not detected) can happen frequently. However a “false positive” where the DNA is detected in a PCR test, but is not actually there can (generally) only happen if: a) samples are incorrectly gathered/handled/processed. Therefore, PCR testing of samples is highly reliable. When a test comes back positive you have crypto (unless there is a clerical error so running a second test is a good “just in case” practice.) Please see best practice for crypto testing below.
With PCR testing, you can collect either fecal or regurgitation swab samples to be tested. Your vet can also use Univeristy of Florida Zoo Medicine which is top notch. https://labs.vetmed.ufl.edu/all-tests/zoo-med-infections/ or other facilities. Lay people cannot send samples to most universities.
The list below are some of the labs we have used for testing:
- RAL (Research Associates Laboratory) COST: $20 for Cryptosporidium serpentis, $25 for Crytopspridum serpentis and varanii https://www.vetdna.com/test-type/reptiles, and
Veterinary Molecular Diagnostics; http://www.vmdlabs.com/herp.html,
Zoologix also does PCR testing: $115 per single cryptosporidum assay (test) and $188 for a whole panel that detects multiple crytosporidium species. https://www.zoologix.com/index.htm.
Your vet can also use Fishhead labs for both necropsy and diagnostic PCR testing: https://www.fishheadlabs.com/.
FACTS:
There is no current cure for Crypto, and as far as we have been able to tell it is universally lethal. However, how long it will take until the animal dies varies and some animals live long lives as carriers without outward symptoms. It can depend on their condition, immune system, age, and other factors. A couple of studies are looking at Paromomyacin as a possible treatment, but there doesnt seem to be enough research/data out there about this.
If you find a cryptosporidium positive animal in your collection: (Have an active outbreak) – First: breathe and slow down. Allow yourself time to process and then:
1. Call your vet. We had one exotic vet tell us to destroy our entire collection immediately and that it was impossible to save any of them (even the crypto negative animals). We had another exotic vet tell us we couldn’t have crypto because our snakes were not symptomatic. So, be aware that MANY vets have outdated/incorrect information re: Cryptosporidium management so please do your own research as well. However its good to get a vet you trust involved.
2. Decide what your goal is. (this will depend on how many animals you have, what your living/breeding situation looks like and other factors)
- What we do/did: - immediately isolate and/or euthanize infected animals. We euthanized ( :( ) all positive snakes and all snakes that had been exposed via breeding or feeding to the positive snakes.
- Lock down the house/business. No reptiles in or out for at least 6 months or until you have a crypto negative collection for 12 -24 months straight.
- Alert anyone who you have sold/bought/traded/visited of possibility that their animals may be infected.
CLEANING
How to “KILL” crypto:
It is very very hard to inactivate Crypto. (note we didnt say Kill) As mentioned above, what does NOT work: F10, F10sc, Clorahexadine, Bleach, Hand sanitizer, Alcohol nor any of the cleaners sold at ANY reptile store/expo/shop.
Killing Crypto is a COMMITMENT and is laborious and time consuming and in all honesty is exhausting both emotionally and physically.
1. Buy shoe covers or only use one pair of shoes to enter the Crypto zone. Remove them and change back into your non crypto shoes when leaving the Crypto zone.
2. Any clothes that you wear into the “crypto” zone should be placed in a plastic bag and then washed in washer with an Allergy/Steam Sanitize setting both in the washer AND the dryer.
3. Use disposable gloves and change and wash hands frequently. Be mindful of what you touch and imagine crypto sticking to them. Anytime you touch a surface assume it is contaminated. Change gloves and change gloves again and again. Do not touch the outside of the gloves with your bare hand when removing them, and turn them inside out when taking them off.
4. Use a dedicated trash can with a lid for the crypto area for gloves/shoe covers/paper towels etc.
5. Do not use any regular/reusable towels to clean areas. Only use paper towels so they can be thrown away immediately.
6. Throw away all contaminated bedding/tools/branches/hides (anything with a porous surface) that may have come in contact with any suspected or known exposed animals.
7. First: wash all remaining items with warm soapy water and rinse well and a lot so that all visible soilage is removed, then allow to air dry. This step will physically wash away many of the spores. (It wont kill them)
8. Soak (all of the areas must be wet the entire time frame) with 12-13% strength Hydrogen Peroxide (HP) and allow to stay wet for at least 4-5 min. OR you can use 6% peroxide and soak for 20 min. We also use RESCUE disinfectant it has AHP but it is unclear if it works as well as straight HP. This step should inactivate the spores but as it is difficult to ensure that all spores are submerged for the allotted time frame it should be followed by the steps below. Wear gloves when using the strong peroxide as it will breakdown any organic surface including skin! It is a very strong caustic chemical so be careful.
9. Put anything that fits in a dishwasher that has a sanitize/steam and high heat setting and run it. Then remove and allow to air dry for 7 days. It should now be clean and free of crypto.
10. You can also steam clean areas but it is difficult to maintain the heat on a surface for extended periods.Steam with minimum 50 psi pressure should be used over the area. You need to keep the nozzle no more than ½ inch from the surface for a min of 2 minutes per section (1-2inch area). It takes about 20 min to cover a 10-20 inch surface area. Now your surface should be crypto free, but leave everything exposed to air for a minimum of another 30-60 days with the item dried out and exposed to air just to be sure (we wait 6 months). Crypto spores do not survive long when dried out. Remember you only need a few spores to infect an animal so err on the side of caution.
11. We have recently read that it is possible to heat items in the oven to 150 F or 60 C for 10 min and that also should inactivate the spores. However this study was done on Cryptosporidium parvuum (that infects cattle) and may or may not hold true for C serpentis/varanaii.
Of Note: Ammonia at 5% can kill spores but it needs 18 hours of direct contact and releases gas fumes that are highly irritating so we dont recommend this method.
Note: This is a synopsis of our understanding and research and experience. Please consult with your veterinarian and reach out with any questions/comments.
https://lafeber.com/vet/bearded-dragon-infectious-disease-slideshow/#tab24
https://journals.sagepub.com/doi/full/10.1177/1040638711403415
https://aidap-infection-control-guidelines.pdf
https://juniperpublishers.com/jdvs/pdf/JDVS.MS.ID.555718.pdf
https://www.wildlifehealthaustralia.com.au/Portals/0/Documents/FactSheets/Reptiles/Cryptosporidium%20infection%20in%20Wild%20Reptiles%20in%20Australia.pdf
https://bioone.org/journals/journal-of-zoo-and-wildlife-medicine/volume-49/issue-4/2018-0080.1/TREATMENT-OF-CRYPTOSPORIDIUM-SERPENTIS-INFECTION-IN-A-KING-COBRA-OPHIOPHAGUS/10.1638/2018-0080.1.short
https://pubmed.ncbi.nlm.nih.gov/24041484/
https://www.sciencedirect.com/science/article/pii/S0304401796010400 T.K.GraczykabR.OwensbcM.R.Cranfieldbd, Diagnosis of subclinical cryptosporidiosis in captive snakes based on stomach lavage and cloacal sampling. Journal of Veterinary Parasitology Volume 67, Issues 3–4, 31 December 1996, Pages 143-151. Accessed 9/5/2022.
https://juniperpublishers.com/jdvs/pdf/JDVS.MS.ID.555718.pdf
JOUR Bogan, James PY - 2019/12/31 “Gastric Cryptosporidiosis in Snakes, A Review” DO - 10.5188/19-05-201.1
O’Rourke DP, Lertpiriyapong K. 2015. Chapter 19 – biology and diseases of reptiles, in Laboratory animal medicine. 3rd ed. Fox JG, Anderson LC, Otto GM, Pritchett-Corning KR, Whary MT, Editors. Academic Press: Boston. p. 967–1013.