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Case Details
Signalment (please inc breed, age, gender): 6mo FN Bengal Cat
History:
Presented with soft faeces and fresh blood in faeces on 10/12/2011 (more than 2 months ago) - intermittent occurrence every 2 weeks / 3 weeks this happens.
The cat is still putting on weight and is otherwise perfectly healthy.
Fully vaccinated, dewormed with both panacur and drontal.
No history of vomit or any other problems gastrointesinal related or otherwise.
Has travelled from UK to Qatar (November)
1. deworming schedule up to date (panacur and drontal in last month)
2. faecal floatation to check for coccidia - negative
3. giardia snap – negative
Resourc
Plan:
1. change diet to hypoallergenic diet
On next presentation:
Powder showed some signs of improvement - no blood had been seen since last visit - faecal consistency looked normal
On next presentation:
Blood in faeces again so I discussed with the O the possibility of more severe IBD and the use of prednisolone requiring a
diagnosis and also ARD.
We took bloods and sent away for folate and cobalamin.
Results;
I explained that this can signify antibiotic responsive D+ and that a trial of ARD triple combo antibiotics would be indicated.
Diagnostics: Lab Tests
High folate and normal cobalamin.
Imaging Results
Question:
1. is there any other DDX I should consider with such values for Folate and cobolamin.
Disclaimer: All advice given is based on the information given. We will provide expert advice, but this is intended only as advice, and not instruction, the
“Feline Expert” does in no way take responsibility for case care. It is for Veterinarian, under whom the case is registered to interpret and act on as their
individual case assessment allows.
Resourc
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2. Considering the fact that it is fresh blood what can I conclude - just that it is probably large intestinal?
3. next steps would be scope if we had that tool - next realistic step is to do X lap? where would you take sample from for X
lap?
Response: You’ve done a really nice work up so far!
The high folate could represent a bacterial floral overgrowth, so probiotics and Tylosin may be indicated in this case.
The fresh blood does indicate a large intestinal disorder, but the folate may suggest some small intestinal involvement too,
even though the clinical signs sound more suggestive of large bowel.
Pure large intestinal disorders are rare in cats, with one exception. This case sounds typical for a newly recognized disease,
a protozoan called Tritrichomonas foetus (T foetus). It has recently been recognized that T foetus is an important cause of
diarrhoea in cat; infecting and colonising the large intestine, and can cause prolonged and intractable diarrhoea. Clinical
signs include increased frequency of defaecation, semi-formed to liquid faeces, and sometimes fresh blood or mucus. The
diarrhea may be protracted or intermittent, with some cats showing a partial response to dietary trials or metronidazole
therapy. Although cats of all ages can be affected with diarrhoea, it is most commonly seen in young cats and kittens, the
majority being under 12 months of age. Most of the affected cats have come from rescue shelters and pedigree breeding
colonies (in the UK we see this disease predominantly in Bengal, Siamese and Maine Coon cats). Abdominal ultrasound
examination may show corrugation of the large bowel and local lymphadenopathy. Colonic biopsies from affected cats
typically show mild to severe inflammatory changes with infiltration of lymphocytes and plasma cells – a pattern commonly
seen with other infectious agents and with inflammatory bowel disease. However, the parasites may be seen in close
association with the mucosa. Although the diarrhoea may be persistent and severe, most affected cats are otherwise well,
and do not show significant weight loss.
Diagnosis
Diagnosis depends on identification of the parasite within the cats faeces. This can be done using a variety of techniques: i)
looking for moving parasites in fresh faecal smears (I’ve attached a video of these parasites) (ii) using a specific culture
system or (iii) by detection of T foetus DNA using PCR. PCR is by far the most sensitive test, but even this can be hampered
by intermitted shedding of the parasite, in one study confirming the presence of parasites in 34/36 cases, compared to 20/36
for culture and 5/36 for direct assessment. The PCR is most accurate if the cat has not received antibiotics prior to testing,
so I would ensure she is off for at least 2 weeks first. Capital Diagnostics or SAC can run the PCR, if you are able to ship a
sample to them, details are available at:
http://www.sac.ac.uk/consulting/services/s-z/veterinary/services/capdiagnostics/tritrichomonasfoetus/
Alternatively, samples can be submitted to the College of Veterinary Medicine, North Caroline State University (USA) for this
test – information on this is available at: www.cvm.ncsu.edu/mbs/gookin_jody.htm.
In addition, for the sake of time/shipping etc, I would have a look-to prepare a smear you are best to swab the outer part of
the stool (ideally mucus covered if possible) and wipe onto a slide with a drop of saline. As the parasite dies in 20 minutes
you need to look at a very fresh sample, so you’d need to hospitalise the cat and have someone keeping a careful eye on her.
The culture system uses an “in Pouch TF test” so you would need to order in the culture media and as the parasites can die
in transit I don’t think that this would be ideal for you.
Prognosis
If left untreated many cats will cease to demonstrate clinical signs between 1 and 2 years of age, although they may still
carry and shed the parasite. However, some cases will demonstrate ongoing signs, potentially due to widespread damage of
the mucosal wall. If treated the majority of cats respond well, although, again in cases with severe damage some signs may
persist even after successful treatment. In addition, we generally do not recommend leaving cases untreated, as long-term
inflammatory stimulus is known to be a pre-disposition for the formation of neoplasia in the cat, and whilst there is no
evidence at this point that this occurs with this particular infection, a wide variety of other stimuli have been shown to predispose to neoplastic transformation in this species.
Treatment
T foetus is resistant to most anti-protozoal drugs such as fenbendazole and metronidazole. In fact, the only drug that T
foetus appears to respond well to is ronidazole (JVIM, 2006;20;536). From limited studies its use appears to be relatively safe
in cats, although a small number of patients have developed neurological signs e.g. twitching and seizures, which have
resolved on stopping the drug (similar to the signs seen with metronidazole in some cases). In the majority of cases, clinical
signs resolve quickly after discontinuing the drug. However, ronidazole is not licensed for use in cats; it should only be
used with caution and with informed, signed, owner consent. Studies have shown that resistance is uncommon, and
Disclaimer: All advice given is based on the information given. We will provide expert advice, but this is intended only as advice, and not instruction, the
“Feline Expert” does in no way take responsibility for case care. It is for Veterinarian, under whom the case is registered to interpret and act on as their
individual case assessment allows.
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therefore we suggest you use the lower end of the dose is initially (30mg/kg sid for 2 weeks) or cats with hepatopathy;
(10mg/kg once daily for two weeks). If Powder does not respond to this the dose can be increased to twice daily, and
ultimately to 50mg/kg up to twice daily. Ronidazole is not available as a prescription drug in the UK, although Ronidazole
(5-10% powder preparation) is commonly used to treat trichomoniasis in birds (e.g. pigeons); the manufacturers will not
release information on what the remaining 90-95% constitutes and anecdotally, clinical signs have been seen more commonly
when these preparations are used. In the UK we have gained permission from the Veterinary Medicines Directorate (VMD) to
use 100% pure chemical grade Ronidazole to treat T. foetus infected cats. This can be obtained upon receipt of a signed
named-animal prescription as capsules from Nova Laboratories, Tel: 00 44 116 223 0099. I believe that Ronidazole is available
in the US also.
Care should be exercised in the use of ronidazole, as there are very few studies of its use in cats, and long-term studies in
other species have suggested some potential toxicity concerns including carcinogenic potential (similar to metronidazole).
Careful handling of the drug is therefore advised. It should never be given to pregnant queens (or queens about to be put to
stud): it is very teratogenic and may result in a number of different and severe defects.
Can T. foetus infect people?
There are reports of Tritrichomonas infections in people, although T foetus is rare. Therefore, it is thought highly unlikely
that T. foetus is will infect humans; however as a precaution people in contact with infected cats are advised to take basic
hygiene precautions to avoid ingesting the parasite.
Other differential diagnoses:
Other causes of large bowel diarrhoea include giardia (mixed sm and lg often)-snap neg.; parasites (may be worth repeating
faecal as a single sample is only 70% sensitive, 2 samples 95% and 3 99%)-but the worming history is good, so I think this is
unlikely; inflammatory bowel disease/food hypersensitivity-No response to diet; to rule in or out you need biopsies-and
biopsying the colon is not without risk. However, the remaining differential is as you said neoplasia. So if this isn’t T foetus,
your treatment/diagnostic options are Tylosin and Probiotic with diet; ex lap (with associated risks) or treatment trial with
Prednisolon+/- Chlorambucil. My approach would be test with smear and PCR for T foetus, if positive treat with Ronidazole
(explaining risks to owner); if neg treat with probiotic and Tylosin for 4 weeks, if not better, two weeks later re-test for T
foetus, and if still negative, advise either ex lap or Pred/Chlorambucil trial.
Hope this helps-if you require further advice on this case, please email this form back to me, with further queries attached
(there would be no further charge for on-going advice).
Sincerely,
Dr Kerry Simpson BVM&S Cert VC PhD FACVSc MRCVS
RCVS Specialist in Feline Medicine
The Feline
Expert
Disclaimer: All advice given is based on the information given. We will provide expert advice, but this is intended only as advice, and not instruction, the
“Feline Expert” does in no way take responsibility for case care. It is for Veterinarian, under whom the case is registered to interpret and act on as their
individual case assessment allows.