All I Know About Tritrichomonas Foetus – by Dave Condon, Highgait Cattery

Since many of you may not be inclined to read all of this let me state
here that the information I am giving is from material published by Dr
Jody Gookin ( and email
correspondences with her. Additionally the folks at BioMed and Westlab

TF is an emerging parasite in the feline world. Surveys have suggested
that approximately one third of all purebred cats are infected. It is
rarely tested for and may be responsible for many of the cases of
chronic diarrhea (e.g. IBD) in cats. If you are a cat owner please take
some time to read this page and acquaint yourself with this ‘new’ parasite.

Where did TF come from?:Tritrichomonas foetus (TF) is a protozoan that
infects bovines (cattle). It is considered a venereal disease in that
industry. It was first discovered in felines in 1996 but was not
associated with diarrhea in felines at that time. As best as I can learn
it appears that Dr Jody Gookin made (or suspected?) this association in
1999. The other researcher investigating TF is Dr Stan Marks at UC
Davis. Why TF was not considered more widely as a cause of diarrhea in
cats until very recently is a mystery to us.

A TF organism looks very similar to Giardia so if viewed by in a fecal
smear a misdiagnoses of Giardia is common. Fecal floats and Giardia snap
tests are insensitive to TF. TF is a fragile organism whose life span
out of the body is normally less than an hour. This lack of hardiness is
due to the fact that TF cannot form a cyst. ). If TF drys out, if it is
refrigerated or if it experiences temperatures above 105°F it will die.
Obviously bleach will kill it too but it will probably be dead by the time you
clean the surface. The primary infection path is probably the litter box
where a well timed use by two cats can transfer the parasite fecal/orally. Dr.
Gookin has commented that TF can live for 3-4 days in a wet stool (wet
is the key word).

TF lives in the intestinal lining of the large bowel. It causes “cow pie”
like stool that is often gassy and malodorous. The health of the cat is
not usually adversely affected. Several breeders have commented that in
symptomatic cats that the smell of the stool is a significant clue of an
infection. It is important to note that an infected cat may or may not have
clinical signs of TF. I have a positive female that has good stools. Infected
cats can treated with Ronidazole. Cats not treated usually cure themselves of
the parasite within 2 years (9 months is the median).

Our TF History: We first learned about TF in January 2006. The symptoms
of this parasite matched some of the symptoms we were seeing in some of
our Abys. We purchased the equipment and tests required to detect TF and
began testing in February. We found TF in 10 of our Abys (8 adults and 2
kittens). Working with our vet we have treated our Abys and are now
regularly testing to insure our Abys are TF free.

Current TF Status: Since our initial TF test we have performed 110 TF
tests. All of our adult female have now repeatedly tested negative. None
of our kittens in our current litters have tested positive. We do have
one new problem. Two of our young intact male studs have failed
treatment. A theory has been proposed by Dr Gookin (TF researcher) that
intact males may be able to harbor TF in their sex organs which may be
beyond the reach of the drug used to treat TF. We are now treating these
males with a different drug. It will take about three weeks before we
know how effective this treatment has been. These males have been
isolated so they do not pose a threat of infection to our other Abys.

There are three testing methods I know of. 1) The least sensitive method is
a microscopic examination of a fecal smear. The probability of detecting
TF in an infected cat has been estimated to be less than 20%.
Additionally two other organisms, Giardia and Pentatrichomonas hominis
may confuse the diagnosis. 2) The gold standard of TF testing is a
Polymerase Chain Reaction (PCR) test. A stool sample can be sent to
Dr Gookin’s vet college (
for this test. This is a very sensitive but unfortunately very
expensive ($100/ test) test. 3) Alternatively, you or your vet can use the
BioMed Diagnostics InPouchTF test ( 1-800-964-6466.
This test is about $5/test and when you consider the number of tests that most
of us will have to perform this is the only sensible economic approach.

I decided to do my own tests and then have my findings confirmed by my
vet (she did not offer TF testing at the time). I purchased InPouchTF
tests and to be sure I knew what to look for, I also purchased a positive
live TF culture. Initially I sampled our Abys by inserting a Q-tip
(cotton bud for our Aussie friends) wetted with fluid from the pouch
into their rectum. Later I began using stool samples but I only used
those that we just deposited. You need use only a tiny amount of fecal
matter (wet just 1/4 of the tip of the Q-tip) or the bacteria in the
stool will overwhelm the antibiotics in the pouch and turn the culture
very cloudy. Fecals don’t have to be incubated but I prefer to speed the
process among by incubating. Normally, positives are seen in 3-4 days
but the range can be broad. My earliest positive result was “immediately” and
the latest was 10 days. You must keep the pouches for 12 days before you can
declare a negative. Another note, Giardia may exist in the pouch for
the first 24 hours, so always monitor positives for a few days.

A low cost microscope is all you need to examine these pouches for TF.
Once the pouches are inoculated, you never need to open them again. You
examine through the pouch. I bought a microscope off of Ebay for $45. You
need 40X and 100X magnification. Your scope should also have an iris to
control the illumination of the sample. TF doubles in the pouch every 8
hours. A positive culture is not subtle, you will hundreds of thousands
of organisms. So if you can focus a microscope, you can perform this test.

Prognosis: Until Dr Gookin published her findings last year there was no
effective drug treatment. Dr Gookin has stated that “Most cats have
spontaneous resolution of diarrhea in two years. More than half the cats
remained positive for presence of the organisms however, up to 4-years
after diagnosis and possibly many can carry the infection for life.” In
a multiple cat environment this could mean an endless cycle of reinfection.

Working with my vet, we confirmed my positives and she phoned in
prescriptions to the pharmacy Dr Gookin’s recommended: Westlab Pharmacy
(352) 373-8111. With the scripts in place I deal directly with Westlab.
They are extremely helpful. Give them the weight of the cat and they
will make up capsules of Ronidazole. Cost is approximately $12 per pound of cat
for a two week supply (given twice a day). Another note: the dosage
range is very narrow, typically 35-45 mg/Kg. If you have a kitten
rapidly gaining weight, the dose my go sub-therapeutic in the second
week. Westlab can make you extra capsules to compensate. Keep weighing
your cat(s). Kittens as young as 6 weeks have been successfully treated. My kitten was 13 weeks.

The Ronidazole used by Westlab is imported from Belgium, it is 100%, not the
10% concentration used for pigeons. Doses, even for cats, are in small
#4 capsules. I’m told it is a very bitter drug and cannot be compounded
to be made palatable for cats. This drug is a potential carcinogen in humans.
The toxicity in felines is probably not known. Temporary neurological side
effects may occur, especially at doses of 45 mg/Kg and above. So far, we have
seen no negative side-effects. We are dosing at 35-40 mg/Kg with very positive
results. Stools returned to normal in less than a week.

As for other side effects, I have received one email reporting that their cat
experienced liver failure while on RDZ. Fortunately it was reversible and the
cat returned to normal. It is not known if this cat was treated within the
recommended dosage range. There are some, not necessary the one who had the
liver problem, who in an effort to save costs who are using RDZ formulated for
pigeons which at a 10% concentration. Accurate measuring and dosing with
this form of RDZ may be difficult. We have experienced no adverse
side-effects nor has any others been reported to us. Westlab have said
that they have had reported to them some temporary neurological symptoms
in a few cases but in large side-effects are few.

Post treatment testing can begin 3 days after the last dose. Westlab
told me there have been some failures, but most these were at the 30 mg/Kg
dose. They assumed that a second course of treatment was successful
since they have not received any call backs. According to Dr Gookin a
relapse can occur up to 20 weeks after Ronidazole is discontinued.

We begin testing 10-14 days after RDZ treatment. We wait this time period to
make sure that no residual RDZ is present to bias the test. We are repeating
the test approximately every 14 days afterward. We expect to lengthen this
period slowly until 20 weeks is reached. Since cats have sensitive guts,
diarrhea (and vomiting) are not unusual occurrences in cats. If we observe any
loose stool we test it. So far these events have been transient and these
tests have all been negative.

**UPDATE JUNE 2006**
As previously posted I reported a problem treating TF two intact male
Abys with ronidazole (RDZ). I have sent Dr Gookin TF cultures from these
males and in time she will test them for RDZ resistance. A resistance is
probably unlikely unless it is gender specific (possible?). Dr G also
suggested that the TF may be able to hide in the male sex organs. This
is just a educated guess not fact and the main reason why I want to hear
from anyone who has or had problems treating male cats for TF.

We also had an additional male relapse. This male was infected when he
was intact but neutered before treatment. He remained TF negative for
six weeks but relapsed when placed in a new ‘only cat’ home. Our seven
females are still negative and so far none of the kittens in three
litters have tested positive. In our cattey we test for TF alot, since
mid-Feb we have performed 124 InPouch TF tests.

The two intact males have just completed a 10 day course of tinidazole
(TDZ). We are now in the wait period before testing. Preliminary results
are about a week away. Neither have any symptoms of TF. Keep in mind
that many adult cats are asymptomatic. This is why TF testing is so
important if your trying to clear TF from your cattery. Assuming you can
clear TF by just medicating is like assuming you can clear RW without
fungal cultures. It is possible but not probable.

A common thread among most breeders I correspond with is the lack of
testing. Most will test symptomatic cats, some will test asymptomatic
cats and a very few will perform post treatment TF testing . Most will
rely on the observation of symptoms. If we did this we would have
declared our two infected but asymptomatic males clear of TF. Then it
wouldn’t be difficult to see how another round of TF infection could occur.

I realize unless you have a vet who is testing for the cost of a test
pouch because he/she wants to learn (has happened) that testing can be
expensive. The only alternative that is cost effective is to DIY. To get
started you need to invest $200-250 for a microscope, electronic
thermometer and 20 test pouches. Payback is quick and since you sample
and inoculate the pouches yourself the likelihood of the TF in the
sample dying on the way to the vet clinic is greatly reduced. Also
interpretation of the results is very easy, no vet or biology skill needed.

The information sources: Material published by Dr Jody Gookin
( and email correspondences with
her. Addition information was obtained from the folks at BioMed
( and Westlab Pharmacy ( Also
experiences and the experiences of other breeders who are corresponding
with us were included. Neither I nor any breeder I know would suggest
that anyone, in matters of feline health, treat their cats independently
of their vet.

Additional TF information

Dr Gookin’s TF paper:

Dr Gookin’s (May 2006): Efficacy of Ronidazole for Treatment of Feline
Tritrichomonas Foetus Infection (abstract is free, the rest will cost
$30, worth it if you have an infected cat):

— Dave Condon, Highgait’s Paws Cattery