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For tortoise, terrapin and turtle care and conservation


Stuart McArthur, BVetMed, MRCVS (Former Veterinary Liaison Officer of the BCG)

The Tortoise Clinic, Holly House, 468 Street Lane, Moortown, Leeds LS17 6HA

email : hohovet{at}

Tel 1: 0113 269 0627

Tel 2: 0113 236 9030

Fax : 0113 266 3048


Many of the recently imported Testudo horsfieldi acquired by members of the BCG have been suspected of harbouring cryptosporidiosis. This in turn has caused alarm and made many keepers worry about their own health if they care for this species. I have put the following short article together in an attempt to let you know what it all means if you get a cryptosporidiosis positive case (in essence: try not to worry, but wash your hands a lot and be hygienic!!!). I also care for some of the Russians from the affected batch and I’m quite happy with mine!

(I wear disposable gloves when handling reptiles; I wash my hands a lot anyway, and I keep my reptiles as though they all carry viruses and salmonellosis which might make others ill. This way I don’t get many health problems!)

Under experimental conditions, the most common reptile cryptosporidium isolate Cryptosporidium serpentis has been unable to infect mammalian hosts, and the human pathogen C. parvum has been unable to infect reptiles (Fayer et al 1995). Therefore, it is most probably incorrect to consider reptile-associated cryptosporidiosis as able to affect the health of humans, or to be a zoonoses. No case of chelonian to human transmission of this disease has yet been recorded. However, until further information is available, the outside possibility of cryptosporidium transfer from reptiles to immunocompromised humans should be seriously considered. Immunocompromised persons should generally not be in contact with reptiles anyway as a result of the greater concern of salmonellosis, which all keepers should be aware has a high natural prevalence in wild and captive chelonians. In the USA, the Centre for Disease Control (CDC) has published guidelines for the prevention of salmonellosis from reptiles and it is wise if keepers of chelonians follow these guidelines in Britain too.

  1. Pregnant women, children less than 5 years of age and persons with impaired immune system function (e.g. AIDS) should not have contact with reptiles.
  2. Because of the risk of becoming infected with salmonella from a reptile without direct contact, households with pregnant women, children under 5 years or persons with impaired immune systems should not keep reptiles. Reptiles are not appropriate pets for childcare centres.
  3. All persons should wash hands with soap immediately after any contact with a reptile or reptile vivarium.
  4. Reptiles should be kept out of food preparation areas, such as kitchens.
  5. Kitchen sinks should not be used to wash food or water bowls, cages or vivaria used for reptiles, nor to bath reptiles. Any sink used for these purposes should be disinfected after use.



Coccidians of the genus Cryptosporidium have been described in turtles and tortoises, but only rarely associated with disease. Wright (1997) reports asymptomatic cryptosporidium infection of Geochelone elegans and Clemmys muhlenbergi (i.e. these animals appeared to be healthy and normal). Most references suggest the organism uneventfully inhabits the upper digestive tracts of chelonians, and occasional anecdotal reports suggest regurgitation and gastritis may result (Graczyk and others 1998). Gastritis and regurgitation was associated with Cryptosporidiosis in two species of tortoise (O'Donoghue 1995). Cryptosporidiosis in Testudo kleinmanni was associated with parasitism of over 80% of the epithelial cells of the small intestine resulting in a diffuse chronic severe peritonitis and ascites (Graczyk and others (1998). Pseudomonas maltophila was cultured from both the cloaca and coelomic fluid. Presenting signs included a severe oronasal discharge and the animal was thin and dehydrated. The authors propose that the Cryptosporidium sp. was a contributing factor to a bacterial enteritis, septicaemia and peritonitis, which resulted in death.


Oocysts (~5µm) are most easily detected using phase-contrast microscopy after faecal flotation. They must be differentiated from yeasts and can be identified using acid-fast stains. Alternatively, immunofluorescent (merifluor IFA) and other assays are more sensitive than older methods. Faeces, gastric wash fluid or fluid collected by enema may be evaluated. For routine screening, faecal samples can be taken to a veterinary surgery, although it should be remembered that affected animals may not always shed the agent in faeces at all times and so may require repeat screens over time to guarantee them being clear. Where collections include especially rare specimens it may be wise to contact your own veterinarian for advice regarding more extensive and immunosupressive screening methods.


Virtually all anticoccidial agents have failed to control both human and animal Cryptosporidium sp. infections. No treatment product is commercially available at this time. Management in animal outbreaks is generally based upon routine faecal screening and isolation and/or removal of positive animals.


The presence of Cryptosporidium sp. in chelonians should not necessarily give cause for serious concern for those who keep them. It is unlikely that such organisms will pose a realistic threat either to the health of a chelonian or to any humans in contact with it. Measures already described above to decrease the possibility of reptile associated salmonellosis, should already be in place. These will be adequate to protect the health of keepers. All reptiles should be kept hygienically and with an understanding of how and why they may cause human enteric disease should inadequate precautions be taken. It is possible that chelonian derived cryptosporidiosis may cause serious disease in other species of reptiles following exposure. Therefore, it is important to isolate any affected animals in order to reduce any possible spread. Chelonians are best kept in small, closed groups of a single species. Procedures to isolate and quarantine chelonians in larger collections should always be in place anyway in order to protect against viral disease outbreaks, and these will greatly reduce the spread of this and any other agents wherever significant numbers of reptiles are kept.


Fayer R., Graczyk T. and Cranfield M. (1995)
Multiple heterogeneous isolates of Cryptosporidium serpentis from captive snakes are not cross-transmissible to neonatal BALB/c mice (Mus musculus)
J. Parasit.

Graczyk T.K., Cranfield M.R., Mann J. and Strandberg J.D. (1998)
Intestinal Cryptosporidium sp. infection in the Egyptian tortoise Testudo kleinmanni
Int J Parasitol. 28 (12) pp 1885-8

O'Donoghue P.J. (1995)
Cryptosporidium and cryptosporidiosis in man and animals
Int J Parasitol 25 pp 139-195

Wright K. (1997)
Cryptosporidium controversy: When do you consider a reptile crypto free?
Proc ARAV 1997, Houston p 169-173

The above has been modified from:

Innis C. and McArthur S. (In preparation)
Digestive Tract Disease
In: Medicine and Surgery of Tortoises and Turtles, Blackwell Science, (Eds McArthur S.D.J., Wilkinson R.J. and Meyer J.) to be published 2003