Failed and ‘phantom’ pregnancies – a hidden killer

For the last 9 years or so I have been collecting information about failed pregnancies following a period of three years when one of my queens repeatedly failed to conceive, or had pregnancies that she resorbed before coming to term. I discovered quite by accident what the problem was, and after that she had three successful litters, some of whom have appeared at Tonkinese shows, and their descendants are breeding successfully.

When I first started looking at conception problems outside my own household I found that there was a surprisingly high incidence of failed or ‘partially-failed’ pregnancies in the Tonkinese. My first information came from friends who had visited the same stud I had been using, round about the time I had visited him, but as I looked further I realised that this was happening to a much broader group of studs and queens, and was affecting such a wide variety of bloodlines that it could not possibly be a genetic issue, or something coming from just one stud.

Tonkinese are a fertile breed, commonly producing litters averaging six good healthy kittens, and almost always conceiving on their first mating. Because we don’t have a tendency to advertise our failures many people were treating failed matings, failed pregnancies, or litters born with some (or all) tiny ‘mummified’ hairless, dark brown (stillborn) kittens as ‘just one of those things’. They didn’t realise that actually rather more people were having this experience than statistically there should have been, so it wasn’t just a one-off bit of rare bad luck.

My queen’s first attempts to become pregnant were pretty hopeless. She was in the pink of health, calling lustily and there was nothing I or my vet could see that might prevent a pregnancy. After two failed matings I tried leaving her with the stud until she was well into her pregnancy in case the journey to and from the stud was upsetting her; I tried antibiotics before during and after mating; I tried fertility drugs, all without a full-term pregnancy resulting, though a scan during one of the pregnancies did indicate that she had conceived, she was just resorbing all the kittens before they came to term.

I had pretty much given up on this queen – Reckless – and assumed that there was something wrong with her and she would never conceive, when I had a Chlamydia scare in my house: I had brought in a Siamese kitten from another breeder (so that he could go to a new home with one of mine) but unknown to me he arrived with Chlamydia, and gave it to my Siamese queen and her kittens. At the time I had an elderly girl with a fresh corneal graft and, as anyone who has experience of this disease will know, Chlamydia usually shows up in the eyes, and involves the cat rubbing at its eyes until they are swollen and sore. Fortunately the Siamese group were living apart from my Tonkinese and I instituted strict barrier nursing, but my vet was as concerned as I was about the potential for the cat with the graft to tear her eye apart if it started itching, so we dosed all the cats in the household with Doxycycline (the only antibiotic effective against Chlamydia, and not normally administered for any other reason). Fortunately the disease didn’t get into the rest of the house, but there was an unexpected bonus: before I knew what was happening I had a litter of five wonderful kittens from Reckless and my own stud boy. The only thing that had changed for her was the course of Doxycycline.

So what was going on?

First of all, it’s important to understand a bit about Feline Chlamydiosis. Chlamydia is often referred to as a virus, since it behaves very like one, but actually it’s a bacterial infection. This type of micro-organism is also known as an
obligate (can't survive without) intracellular (living inside cells) parasite (where it takes but does not give back). It is virus-like, because it is dependent on molecules from its host organism to reproduce. One way in which it is notably bacterial rather than viral though is that it can be killed by an antibiotic, although it is very hard to destroy even so and requires a long course of a particular antibiotic of the Tetracycline family. Viruses are not susceptible to antibiotics.

The commonest form of Chlamydia that cat breeders see is the form that I had, which causes massive irritation of the mucous membrane in the eye, made to look worse particularly in adults as the cat rubs the eye because it itches so much.
Kittens manifest Chlamydia as ‘gummy eyes’ – lots of pus sticking the eye shut. Anyone who has had Chlamydia of this type in their cats will know that it’s the very devil to shift! While the symptoms are visible you know you have a problem, but the symptoms can disappear of their own accord leading the owner to conclude that their cat is healthy. However the disease is lurking in the optic nerve, just waiting for an excuse to become active again.

Many breeders have found that after a 10-day course of Doxycycline (the recommended course of treatment) the cat(s) may look fine and the infection has apparently gone (the cat may even produce a clear test swab), but a couple of months later they have a cat with a raging eye infection again. The only way to be sure of clearing
Chlamydia is to give every cat in the household a long course – up to 6 weeks – of the drug.

Chlamydia is also notoriously difficult to test for, since it is extremely vulnerable outside the body: it cannot survive outside the host cells, so swabbing for it is very difficult indeed and the results are often inconclusive. The commonest manifestation of this form of Chlamydia in breeding households is when a breeder finds that every litter of kittens gets gummy eyes around the age of 2-3 weeks, but the gumminess clears up with time. In this situation it is likely that the whole household is infected, and all the cats – adults and kittens – would need to be treated to clear it.

There is one final problem in identifying the presence of this disease in a cat or household: some cats can recover from it without intervention; their own immune systems eventually killing the bacteria. The disease can however lie dormant for long periods, sometimes years, particularly in neuters who do not have the ‘stress’ cycles of calling that entire females go through. The disease will only usually re-surface in response to stress and sometimes never manifests at all in the carrier, only in cats that come in contact with the carrier.

This is not the only form of the disease: Chlamydia can go systemic, invading the whole body of the cat. Symptoms include a raging temperature, and the related illness and debility that go with this. Cats very often die from this form, since by the time the vet has tried everything else to cure it, and sends off some blood to test for Chlamydia, the cat is too ill to be saved. I know of three separate breeders who lost cats to systemic Chlamydia because their cats had been vaccinated against it, so the vet did not believe Chlamydia could be the cause of their illness. Sadly, when the vet did send off bloods, the cats died before the results came back.

Chlamydia is also a sexually transmitted disease. Anyone who has sat reading the notice-boards in their doctor’s waiting room in the last few years will be well aware that a significant percentage of the population carry the human version of Chlamydia without ever feeling ill or even knowing they have it. It is known to cause infertility and other problems relating to conception, and it can also increase the chances of infection with HIV.

It’s not rocket science to work out what happened to Reckless: she became infected with the STD form of Chlamydia, and repeatedly failed to carry a pregnancy to term, despite being apparently healthy. The disease was lurking in her uterus, and every time her body was put under stress through calling, mating or pregnancy, the bacteria became active and caused her to resorb her kittens. In a way I think I was fortunate: other people who visited the same stud around the same time had litters with some living kittens and some tiny dead but apparently fully-formed kittens, which was quite upsetting to see. It is very important to note that all of the queens in the first group of three that I identified were maidens, so could not possibly have picked up this illness from another stud. It must have come from the one boy that we all went to. And in case anyone is worried, that boy subsequently sired successful litters and has since died a natural death, so he obviously managed to throw the disease off, and it was probably only active in him for a period of around 6-8 months.

It appears that what the bacteria does is to upset the natural resorption process, so that either a queen resorbs her whole litter, or kittens are born partially resorbed (the little ‘mummified’ ones). I sat and watched with one friend while her cat delivered 10 of these tiny kittens, and two living kittens, one of which did not survive beyond 24 hours. Having too many kittens is equally a malfunctioning of the normal resorption mechanism.

None of the cats I have heard about, then or since, were unhealthy, came from unhealthy lines or had any other reason not to conceive. As recently as last year a breeder told me that her girl had been to stud four times without result; after I told her about my own experience she spoke to her vet, who agreed that Doxycycline was worth a try. After a 10-day course the girl had a successful and normal litter (with a different stud). Only a few months ago I heard of another cat belonging to a different breeder whose cat failed to conceive with the same stud, so there’s no question that the problem is still out there, and working out what is happening is, as I said before, not rocket science…

Like it or not, it seems that our studs and queens are passing around a sexually transmitted disease that we don’t (and frankly cannot) test for. Looking at the information I have collected it appears that some queens or studs can recover spontaneously, while others remain infected either permanently (until treated) or for a short time; just long enough to experience problems with conception or pregnancy. Studs may go through a period, short or long, during which they do not sire any litters, or have a higher than usual incidence of failed matings, while others may have problems with one queen (or more), but not with others, suggesting that the queens are infected, but they are not passing it on to the stud, or that the disease is not active in the stud all the time – possibly the disease is going through a dormancy period, or the queens have a good enough immune system to deal with the bacteria naturally.

Obviously I recognise that sometimes cats do not conceive, and there’s nothing abnormal about that within reasonable parameters, but this should be a much rarer occurrence than it is. I’m not advocating giving all our cats an antibiotic as strong as Doxycycline, but I am asking breeders to be wary and aware: if your queen does not conceive after a mating, do NOT go to a different stud! If she has Chlamydia you will just be passing it on. If you decide to take your queen back to the original stud and she conceives, then you know that your original failure was probably just ‘one of those things’ – it can happen (most often with maidens) – or possibly that your queen has thrown off the STD by herself. If she fails to conceive on her second visit though, the likelihood is that there is some problem, and although there can be other causes for infertility, the most likely one is this disease.

Try giving the queen a 10-day course of Doxycycline and then go to a different stud (in case the cause was Chlamydia and the original stud is infected) – or if the original stud owner is willing perhaps they will also give their boy a course of antibiotic, but again I would fully understand anyone being unwilling to do this without ‘proof’ of infection. Sadly though, there is almost no proof to be had. If, like my Reckless, the queen fails to conceive repeatedly, but after a dose of Doxycycline does conceive, then that’s the closest you will get to proof, and it has succeeded often enough that I am convinced that there is a problem out there – as is my vet: I put all my information to her, and she agrees that the case histories suggest that a high proportion of the cats delivering ‘problem’ litters (particularly the ones with partially resorbed kittens), or having trouble conceiving almost certainly have either Chlamydia or something that behaves almost exactly like it.

What is crucial is that the stud boy does not have another queen visiting after a failed mating until the cause of the failure has been established. Unless the queen is a maiden, she could have caught the illness at her previous stud and may not have passed it on to her second stud, but you can’t count on that. If you think about it, just one stud having this problem could lead very quickly to a widespread propagation of the disease: a queen goes to stud, comes back with Chlamydia, fails to conceive. She then goes to another stud (giving him Chlamydia as well), meanwhile the first stud is mating other queens, who will also go on to other studs, and the second stud is likewise working. So stud owners have to more wary than owners of queens. Ignoring the possibility, or taking the suggestion as a personal slight and insisting that there couldn’t possibly be anything wrong with your boy is no help to anyone: nobody is saying that you’re doing this on purpose!

The upside is that the infection isn’t necessarily permanent in the queens (though it was in mine, lasting through three years of failed matings); it affects each queen slightly differently, so some will carry kittens to term and some will not; some queens seem to be able to throw it off; some are apparently not vulnerable to infection; in the boys particularly it seems to have a naturally limited lifespan (as with the stud that I used originally).

Of course ‘it’ may not actually be Chlamydia – whatever it is though, it behaves like Chlamydia and is killed by the same antibiotics. Can you test for it? Almost certainly not: the bacteria are dormant most of the time, and even when active are in the uterus, and you won’t know when it is active because there are no visible symptoms. Even if your vet could get a swab, the chances of culturing the bacteria are slim to zero – all the vets I asked about testing felt that there was no point in even attempting it. Like many animal illnesses, the best test seems to be the treatment – if it works, then you know what the disease was.

I continue to gather information about failed or semi-successful pregnancies, all of it is kept confidential, and I would be very glad to hear from anyone who can contribute to the data. There is no purpose in naming bloodlines or studs, since nobody would willingly breed with a problem like this. I have spoken to individual breeders or stud owners where it seemed to me that they may be affected by this issue, and naturally have had a mixed response to the idea! This problem is out there though, ignoring it and burying our heads in the sand is costing us the well-being of our cats and many lost kittens, and it is affecting more and more of us. Knowledge is power, so let’s use this knowledge to try and stamp out this particular problem.