Hey guys..... first up - I've been pretty busy trying to juggle full time study with part time work. So I've been quiet over the past few weeks for that reason.
Secondly - We've also been dealing with something else.....
For those who haven't been around as long, I'd like to preface this: I'm an ex-paramedic and I've gone back to full time study as a vet tech. I was very fortunate to be hired as a vet nurse whilst I finish my study, and I graduate at the end of 2022. I mention this because I have a background in human med, and now moving into vet med..... I hope that my insight into this topic holds a *little* bit of weight.
This is an evolving situation, and I will be adding to this over time. I may just keep adding to this post, or I may make additional blog posts. If you're reading this, it's up to date.
I may make mistakes along the way. Please be kind and constructive if you have any feedback.
So... feline respiratory viruses... this is a tricky subject, because as soon as you mention it.... people panic.
My thoughts have gone around in circles with how to share it.... and although people may not read it all, or only read some, and then go off and still panic.... I still think it's important to share.
I've made a point to document a lot of our breeding journey, and so I think this is no exception.
Would you rather know what you're dealing with? I sure would!
Any breeding program with any species, at some point in time, is going to face a health issue with an infectious disease. It could be sheep with clinical footrot, dairy cattle with mastitis, dogs with kennel cough... or in our case... cats with respiratory illness.
Firstly, don’t panic.
Secondly, don’t panic!
I've had a couple of people (not in the breeding world or in vet med) say to me... "well that's it then? I suppose you gotta pack it all up and be done with it?" The short answer is no. I'm not ready to throw in the towel yet.
We would rather detect and respond to these issues, than simply not know, or even worse, try to pretend it’s not happening. Most breeders will have dealt with these issues, but you won't hear about it. We are just choosing to be open and transparent about it.
Feline respiratory diseases (and others) are ENDEMIC throughout the global feline population, including catteries. It is uncommon for a cat not to have been exposed in some way or other – this might have been through a shelter, a boarding facility, going to the vet, attending cat shows, in a breeding situation, or even just visiting a friend’s home and transmitting the diseases via ‘fomites’.
Some people have said, but why would you breed with a cat who has a known disease? These particular diseases can be tested for, but it's tricky, and a lot of people don't understand the intricacies of testing, or how to interpret the results. Breeders may import a cat that already has been exposed even with testing. A cat might be carrying a disease and it may not show it for years.
If every breeder in the world who had exposure to one or more respiratory diseases ended up shutting off their plans..... there would be no cats left, that's how widespread it is. Just because respiratory diseases are endemic doesn't mean it's okay, but it also doesn't mean a breeding program should be abandoned.
Testing for these diseases is tricky, and I’ll explain why.
Also, I think with research and knowledge we have finally put together a plan to "breed around" it.
So.... here's our situation. We are currently dealing with exposure and detection of several respiratory diseases within our breeding program. At first glance, it’s a scary prospect.
Ultimately, we don't know where they came from - it could have been from the US or Denmark, where our imports came from, we could have picked them up at one of the shows, perhaps from a vet visit. Or tracked in from visitors, clothing, shoes, or any inanimate object. Honestly, they could have come from anywhere, but the point is that it doesn't matter where they came from.... just how we respond to it.
One of our queens started exhibiting respiratory symptoms: watery clear discharge from nose and eyes, some sneezing. We obtained a PCR test, which came back positive for feline herpesvirus (FHV), feline calicivirus (FCV) and mycoplasma. I just about died when I heard it wasn't just one, but THREE respiratory diseases.
Let me tell you a little bit more...
Cat flu is the umbrella term for any bacterial or viral feline respiratory disease showing clinical signs. Many people are not aware that these diseases can lie dormant / latent for many months or years.
There are more respiratory diseases than just the three mentioned here.... but for the sake of everyone's sanity and my own tendency to ramble... let's just focus on those three for now.
So if it was lying latent in this queen.... what set it off now?
The most common trigger is stress. Our queen, Adelaide, had been to two shows within a month of each other, and she had also recently been introduced to our other queen's babies after their first vaccinations, when they were just about 8 weeks old. Adelaide struggled with the introduction, and became stressed around them, despite her usually maternal manner. I think instinct kicked in, and she knew they weren't hers, and it was just too much. About 18 days before the introduction to the kids, she had gone to her second show, and so the combination of everything seemed to be enough to trigger it off. She could have gotten one, or all three things, from the show itself, but I didn't see any other cats with clinical signs of anything when we were there. They use F10 Vet disinfectant between each cat, and none of the cats have direct contact. There are also barriers between each show cage. Deep down, I think that the queens (who came together) brought something in from Denmark or our boy brought it in from the US, and we've just been super lucky to get this far.
So I mentioned there's a test which identifies a panel of respiratory organisms. The vet can take a swab from the eye or throat, and send it for for a PCR test (polymerase chain reaction). In a lab setting, the viral DNA is amplified and identified. It’s pretty specific and quick. You may have heard about PCR testing with human Covid19, and it’s the same process.
The tricky part lies with the interpretation of results. It must be done cautiously, and ideally with background knowledge of the cat’s history and whether or not the cat currently has symptoms. There are chances for false negatives, and I wanted to figure out why.
A positive test in a cat with clinical signs:
• The cat has an active virus and is ‘shedding’.
• Shedding means the host-body is releasing infectious virus particles into the environment and passing it on. The virus particles may ‘hop on’ to an inanimate object, known as a ‘fomite’ and be transmitted that way. This includes: clothes, hair, shoes, door handles, surfaces, EFTPOS machines, cutlery, stationary…. Pretty much anything really and in the vet world we often say it’s “a war on fomites” when trying to deal with disease control.
A positive test in a cat with no clinical signs:
• The cat is a carrier of the disease and may be ‘shedding’... or they might not be shedding, it's almost impossible to tell.
A negative test means one of two things:
• The cat is completely clear of the disease, OR,
• The cat has a latent form of the disease, and the viral DNA particles are ‘hiding’ within ganglion nerve cells, and currently unable to be detected > in this instance the cat is not ‘shedding’ (transmitting the disease).
If a cat was previously positive, and is later negative…. It is impossible to know whether the cat has completely cleared the virus from their system, or whether the virus has simply returned to a latent and non-shedding state.
And if a cat has multiple negative results.... again, there's no way to identify whether they really are clear, or just a carrier... but overall, it's likely that if they are a carrier, then they are not shedding at this time.
Cats can carry these diseases in a latent form for years. Even if every breeder PCR tested every cat before bringing them into their home/cattery, we wouldn’t definitively know whether the cat was actually 100% clear of it, or if they are carrying a latent form. The disease may not “pop up” until a certain trigger activates it.
This is why not every breeder will test, or only tests in certain situations.
The best way to choose a new cat for your breeding program would be to have a negative test in a cat with no clinical signs. And this really does seem the 'best' it gets.
When we received all three of our import cats, they did not show any clinical signs before, during travel, or immediately after arrival. We didn't get them tested at the beginning (a) because it wasn't on my radar and I really didn't have enough knowledge yet, and (b) because they simply didn't have symptoms.
Clinical signs and treatment:
Signs include, but are not limited to:
• Watery eyes or nose (clear or purulent discharge)
• A cough or sneeze
• Difficulty breathing
• Fluid build up and congestion in lungs
In general, there is no treatment for viruses. Antibiotics do not target a virus, they just manage secondary bacterial symptoms, so they can help if the symptoms get worse, but they aren’t a viral cure.
There is an anti-viral drug called famciclovir, which we’re looking into. Apparently, it’s specific for FHV. Antivirals carry more risks than antibiotics and the efficacy is questionable.
Herpesvirus (FHV) can have the above signs, and is also associated with ocular (eye) lesions or ulcers. A cat with FHV is likely to become a carrier.
Calicivirus (FCV) can also have the above signs, and is more likely to be associated with oral (mouth) lesions or ulcurs, inflammation in gums, other dental issues, and possibly stomatitis. A cat with FCV may become a carrier, or they may completely clear the virus from their body, but as described with the 'negative' result on a PCR test, we'll never really know if it's gone or not.
Mycoplasma is bacterial, and we’re hoping to eliminate this entirely.
There are no ‘benign’ strains of cat flu, it has to come from a pathogenic organism. Some strains are more or less virulent.
In our breeding situation, and on advice from our vet, we are in the process of blanket-treating every cat with an antibiotic (abx) called doxycycline. This abx is specific for mycoplasma, but it also helps with secondary bacterial symptoms of any viruses they have too.
In this situation, we weighed up the risks vs benefits, and feel that treating everyone across the board with a course of abx (even if not symptomatic) will hopefully eliminate the mycoplasma totally.... and outweighs the potential risks of treatment (abx resistance and upsetting gut microbiome).
In a pet situation, you'd generally only treat with abx if the cat has clinical signs and/or has a positive test.
To help with the gut microbiome thing... we’re giving a probiotic to help replenish the good bacteria that may be wiped out by taking abx. We will get follow up PCR tests to determine the outcome.
So what about vaccinations, I hear you asking?
Here's some info from the 2020 AAHA/AAFP Feline Vaccination Guidelines:
So, in a nutshell, respiratory diseases are vaccinated against. FHV and FCV are two of the diseases in the core vaccine F3. However, the vaccines are not always effective or provide full protection. Which, honestly, sucks.
Indeed, all of our kittens obtain their first vaccinations at 6 weeks, 10 weeks, and 14 weeks as per the recommended guidelines. I'm also thinking of doing a vaccination at 6months old too, which was outlined in that table.
Once Adelaide started showing symptoms, we obviously isolated everyone, but as we all know with human covid, there are long incubation times, and we were too late. Mild symptoms have spread through everyone except our stud boy Henley and our rescue neutered boy Kuro.
So I'm honestly not sure whether the babies have active viruses, or whether their bodies were recognising the viruses (from the initial vaccination exposure) and fighting them off > which is what a vaccine is designed to do. It introduces the virus to the body, and the body develops antibodies towards it... then at the second exposure (the second vaccination) the body recognises it and goes "oh shit, mount your defences and get rid of this thing". Except in this case, instead of an inactivated vaccine, it was the real thing.
I think it's important to note here that I've been completely open and transparent to our A-Litter kitten owners and prospective owners for our current B-Litter.
This may also affect future litters .... and that's why we're developing a protocol to breed around this. Hopefully, after 1-3 generations, we may be successful at raising a generation without any viruses. This is the bigger picture, and what I have to look forward to.
Advice and breeding plans moving forward:
I've obtained a lot of advice from our local vets (where I work), and also some vets at Roseworthy Campus (The University of Adelaide). As a result we have support from a lot of people in this field with loads of knowledge.
Stress is the #1 cause for activation of a latent virus. Diet, housing, hygiene are all extremely important in managing this issue.
Research is showing little evidence of transmission via the transplacental route (known as vertical transmission, directly passed to the baby during foetal development). Babies are likely to be born clear of FHV/FCV and only pick it up via direct contact from the mother shedding the virus - that is, if the mother has re-activated a latent virus during the stress of labour and parturition (birth). This is known as horizontal transmission.
As a result, if babies are isolated and hand-reared from birth, this may have a very good chance at keeping a baby clear of a virus.
Consideration about taking a litter from their mother at birth is multifaceted. Given that commercial colostrum/formula is usually from a bovine species and is not their natural maternal source… does this impact their immune systems later?
Ideally, it's best for a neonate to drink maternal colostrum. But is it too risky in this case? It's possible that maternal antibodies create a latent infection, and if so, is it better then to provide commercially derived colostrum from day one?
Another source says that if the queen has a good antibody titre, the kittens will benefit from high levels of MDA (maternally derived antibodies) from colostrum which will provide protection for the first few weeks of life until vaccination takes place. Additionally, booster vaccinations just before mating may be beneficial (vaccinations after they become pregnant are not indicated). Early weaning around 4 weeks is an option to prevent horizontal transmission, and this may be better than taking the babies from the moment they are born to get at least some socialisation from the mother.
If we did hand-rear from day one... I've wondered how it would affect socialisation of the kittens, and can they still "learn how to cat"? In a different situation where neonates are raised without a mother (say, she died giving birth), they obviously become hyper-socialised to humans.... and for the most part, they seem to do okay. They would still be around each other, and learn a lot of cat mannerisms as they grow anyway.
Obviously, it's far from ideal to knowingly take a litter away from a mother at birth, but can we look at the bigger picture and make this sacrifice now to eliminate these viruses from our program? So the option of weaning early vs taking them immediately should be weighed up.
There is the option of depopulating and repopulating with new breeding stock, however since these diseases are so endemic, we would fall back on the same chance of importing another cat with the same issues.
We feel it's more ethical and sound practice to know where we stand now, and to breed around the viruses with the knowledge of vertical vs horizontal transmission… as opposed to starting again completely with another “mixed bag” of unknowns. Returning to square one seems pointless when we're now already halfway there.
Once our protocol has been developed and we see how it goes over the next several generations, we’re hoping that this can also help fellow breeders who are in the same position. It is in skeleton stages currently. We’ll provide health testing results as they appear.
There have been many instances around the country where breeders are releasing sick cats with no support, and no transparency on why this is occurring. The unknown part is concerning!
We think it is ethically possible to try and breed around these issues. If not us, then who will start? If we give up now, the cycle continues. We've gained some really insightful knowledge from the ethical breeders who have been through this and shared with us. So this is massively appreciated.
We want to foster a culture where can learn and share knowledge. Own your mistakes. Learn from them.
Originally, I really wanted to have everyone running free within our home. In Europe, it's common practice for all the queens and litters to have free-run of the house, and the stud males are in enclosures attached to the house. I wanted this too! They look so happy and enriched.
But..... I think now, it's important to find a balance between enrichment and disease control. And besides..... if the cats are stressed in a more 'free' environment, to the point of activating latent viruses.... is this fair on them?
Here's an excerpt from http://www.abcdcatsvets.org/feline-herpesvirus/#breeding-catteries
And finally.... after all that... here is our current protocol.
Remember it's in skeleton stages at the moment and may be tweaked as we go along.
Breeding Protocol for FHV, FCV & Mycoplasma
1. Separate/isolate cats who are symptomatic or have a positive PCR test (indicates shedding). Also lowers stress by being in smaller groups.
- FCV & FHV supportive care, possible abx for secondary bacterial symptoms
- Mycoplasma – doxycycline – ultimate goal to eliminate entirely
3. Practice good hygiene, remove faeces from trays immediately. Regular cleaning of trays with bleach and F10 veterinary disinfectant and dry in sunlight.
4. Possibly retest 30+ days post clinical signs disappearing. A negative test (on a previously positive cat) indicates that the virus has returned to a latent state > 30 days post absence of clinical signs AND a negative result > the cat is no longer shedding.
5. Boost immune systems of all cats by adding supplements or probiotics
- Lysine - naturally occurring amino acid thought to reduce arginine (another amino acid involved in viral protein replication) so overall it will reduce viral replication and shedding, results seem to vary.
- ProN8ure (orange label, formerly Protexin) https://www.vetshopaustralia.com.au/protexin-soluble?gclid=CjwKCAjw092IBhAwEiwAxR1lRjwNwMTN_FbO-uBXeiT1-4iTaJckD6P_eWPtBf1ArG0HFHFhQ0X6pxoCzJEQAvD_BwE
- Blackmores Paws Digesticare https://www.blackmores.com.au/Products/Pet-Health/Digestive-health/PAW-Digesticare-60?q=150&gclid=Cj0KCQjwu7OIBhCsARIsALxCUaPJ82B55QmWq8WpY9LYiZI5zpIfAFGn72JNmMv8mjj6qtRuKsSV-fYaAkk1EALw_wcB
6. Create an environment with minimal stress, provide a good quality, nutritious and balanced diet > decrease chances of reactivation and shedding.
7. Plan matings based on negative PCR tests and asymptomatic cats.
8. Isolate pregnant queens minimum 3 weeks prior to parturition (birth) – everything will be centred around creating the lowest-stress environment. Two options for raising kittens:
- Take neonates from queen and hand-rear with commercially derived colostrum and milk replacer.
- If queen is asymptomatic during and immediately post-labour and birth, allow her to raise kittens until 3-4 weeks old. Kittens will receive MDA from colostrum if mother has good antibody titre (but is there a way to test for this?) and be protected for the first 3-4 weeks of life.
- Possible to PCR test queens and babies post birth (unsure of timeframe yet) to re-evaluate and determine (as best as possible with limitations of test) that babies are negative.
- Desex queens and stud, may keep entire until reproductive status and breed-health testing of next generation is confirmed > find forever homes for ex-breeding cats and FULLY inform owners of situation, risks of reactivation, advice and provide lifetime support.
**Note: Finding forever homes for retired breeding cats was ALWAYS in the plan. We plan to breed for many years to come and keeping them all is simply not possible. We'd rather a retired cat live out the rest of their days spoilt on someone's bed than having to cage them all here just "because we wanted to keep them"... because ultimately that's what it would come to, and there has to be some give and take if you plan to breed vs just having pet animals. It doesn't mean we don't love them.. heck.. each and every one leaves a forever-imprint on my heart and they'll always be special to me, but if we want to breed - for the purposes of enriching the breed as a whole - then this is what we have to accept.
9. Continue with new generation offspring and bring in new stud and/or queens who have been PCR tested within current environment showing negative test AND zero clinical signs throughout entire lifespan ~ as much as can be determined / again, interpret PCR results cautiously, and at our expense if breeder doesn’t already perform PCR testing / be aware that negative test does not differentiate between latent virus and actually being 100% clear of virus.
10. Prospective homes for CURRENT LITTER
Be open and honest about situation > allow homes to make informed decision
Preferable homes > no other cats, or known active or latent status FHV/FCV+
Home will have full understanding of the risk when bringing in new kitten > may trigger stress and activate viral symptoms and shedding > how to transition slowly is paramount
When managed effectively FHV/FCV+ cats can live a quality life, particularly if kept latent.
We will not release kittens with active viral symptoms. Boost immune systems, return virus to latent state. PCR test and provide results to kitten homes.
I've had a few people ask me: so what does this mean for a cat that may be a carrier, or is positive for a respiratory virus? What's their quality of life? Does their life expectancy decrease? Will they die younger? Will they be sick all the time?
From what I've seen from being involved with rescue and foster cats - where a lot of these viruses go round in circles, and also from my current research - I feel that with good management, many of these cats, particularly with latent forms of these viruses CAN go on to lead really good quality lives.
There are different virulence levels with each strain of cat flu... think cat flu in shelters where the cat's eyes are glued shut due to so much gunk being produced, unable to breathe well due to a lot of purulent nasal discharge, secondary pneumonia - a bacterial infection in the lungs - unable to eat... etc etc. Yes cat's can die from a URI, but I would say that's an extreme case.
In a *well managed* cat, I don't think their life expectancy really decreases, but that is just my (brief) experience over the years with rescue/foster cats, and now with my short time breeding so far. I'd have to look up mortality rates and such to give a more educated answer.
What does good management look like?
The main trigger is stress. Keeping your kitty in a safe, predictable environment, with little change, a good nutritious diet, and regular preventative health care >> worming + parasite treatment (if you choose to do so, some people choose to do things like faecal floats to detect an actual worm burden, or only actively treat fleas if they appear - which is fine, as long as you're on top of it and know the risks either way) preventative dental measures, keeping up with vaccinations, and generally being attentive and picking up on signs of stress, or triggers for stress.
If things do change...... whatever it may be.... as much as possible, do it slowly!
Of course there may be huge unavoidable things, like moving house for a job change.... But there's also little things... and I want to emphasise that both the big and the little things can be prepared for.
Our job is to try and socialise (expose) each kitten to as many everyday sights, sounds, smells, etc, so that they are confident enough and prepared for these types of changes that might occur on a day-to-day basis. We only get 14-16 weeks with them.... so our work is laying the foundation to build their confidence and adaptability.
It's a bit like when you take your dog to obedience classes... they only go for a few weeks, which isn't very long. The dog will never be fully trained in such a short time, and that's not the aim, despite people's misconceptions. The trainers train the humans how to train the dogs. A bit of a tongue twister, right? But seriously, the hard work needs to be done by you.
This is the same for socialisation (exposure) with our kittens. We start the process, and then we'll be there to support you as you continue on with daily socialisation & exposure.
This actually goes for any kitten, and comes with the package anyway - but it's extra important for these upcoming litters.
So how do you do this? The idea is to do things little and often. So that when they are exposed to new, unfamiliar things, they already have a mindset that can handle unfamiliar stuff without totally flipping out.
For the first big transition... moving from our home to yours.. give them a small safe area, it could be a decent sized (dog) crate, with enough room for a litter tray, a bed and their food & water. It could be just one room in the house. At least 14 days isolation from any other pets is a good idea anyway... but in this situation... it's super important... think human covid19 incubation times and quarantine.
Let them get used to the sounds of their new home. Bring in some clothing or a blanket with your scent on it. Interact with them often. When it's time to introduce them to the rest of your house, do it one room at a time, perhaps even on different days. And the same for the introduction to the other animals. If they appear confident and at ease, this is what we're aiming for. If they're timid, it may take a little longer. Some people just want it all to happen *right now*. Remember this transition time is a drop in the ocean that is the rest of their life... decades and oodles of time. So just take it slowly and use it to bond with them.
Once you've successfully transitioned them and they're confident and happy.... now comes the rest of the stuff!
Take them for car rides every now and then...you might be going to get pizza... pop them in their travel crate and take them along for the ride! We've started this, so it's great to continue it. This normalises being in a vehicle, so that when you do need to take them to the vet for their regular health checks, it's not just once in a blue moon and super stressful for them. Some of them are really confident in the car, and can even travel like a dog, with a harness and a seatbelt clip. It really depends on the individual. But remember, with everything, work up to it slowly and increase duration. Think of it like levelling up in a video game.
Groom them often. Brush them using a slicker brush or a greyhound comb. Look in their mouths and ears. Like really open their mouth and touch their teeth - we've done it a lot every week from birth, and doing it now whilst they're young (with us and you) means it's less like handling a wild mountain lion as they grow. I can show you how to do this if you're not confident.
Engage in the dental stuff that I've mentioned in their kitten agreements. This is such an underrated preventative health care strategy: It keeps their teeth in good condition, and saves you a tonne of money on dentals requiring sedation.
Touch their paws. Clip their nails once a month, even if they don't really require it, even if they climb and use a scratching post... stuff like this is important for their confidence, and a well-socialised cat should be at ease when handled regularly. I will make a video / separate blog post on handling and grooming when I have time!
When changing to a new litter or new food (perhaps your regular supplier no longer stocks your brand?) try to do it gradually.... add some of the new to the old.... gradually increase the new stuff day by day, so it's not going cold turkey on them.
Since they are a well-socialised kitten, don't tiptoe around them! Play loud music, turn your TV up, use the hair dryer and the vacuum cleaner around them. Bang a cupboard every now and then. It's okay and beneficial for them to hear and be exposed to all these daily things (because we've already started it!)
Of course, a cat that hasn't had regular exposure from a very young age... don't just throw them in the deep end with some of those things. Some counter-conditioning might be required. In a nutshell, this is a behavioural technique that is used in dogs, wild animals, zoo animals... pretty much across the board in any species. The idea is that you reverse a fear by gently and gradually exposing them to something and creating a new and positive experience/association with it. Come and ask me about it if it's something you'd like more info on. There's heaps of stuff on g*ogle or y*utube about it too.
All of these little things can make or break a cat... and so like I mentioned, we start the process of socialisation/exposure, and we hope you will continue it. A resilient, brave cat is a happy cat. I think overall it helps with stress... and in turn... reduces their vulnerability to infections.
If you've done your research on probiotics and supplements, and feel like it's something you want to try... look into the links I posted above (ProN8ure orange label and Blackmores Paws Digesticare) to boost their immune system even further. These are probiotics, but for cats, and they replenish the good gut bacteria. There isn't heaps of science backing them, so try to make an informed decision. We think the benefits outweigh the risks in this case, and we do use ProN8ure.
Finally, you must keep on top of hygiene!! Clean litter trays daily, and remove faecal matter as soon as possible (immediately, preferred, but most of us have work and life, so just as soon as you see it).
Clean trays with bleach, and everything else with F10 or Virkon (two types of veterinary disinfectants that you can easily source, and have excellent specificity for almost all veterinary-related viruses).
I wouldn't use bleach on everything, simply because it has a smell that cats associate with urination (the ammonia), and they may start to pee on everything that you use bleach on. So that's why it's okay to use it on their litter trays - since they pee there anyway!
I can't stress this point enough: FOLLOW INSTRUCTIONS, DILUTION RATIOS AND CONTACT TIMES. If it says "leave for 10 minutes" then leave it for 10 minutes, any less time, and it won't have killed the bugs yet. Also, more of the active ingredient / product does NOT equal more effectiveness. They've been tested and trialled for a reason, so please just follow the directions. Take note of storage - some products are degraded by sunlight, so don't leave them on a windowsill. The same with expiry dates, the products can degrade and lose effectiveness after a certain time period, and/or after they are mixed with water.
A cat with a latent infection can appear like any other healthy cat, they won't have clinical signs or symptoms and they won't shed any viral particles (if they are truly in a latent state). But you must also remain attentive to their individual needs and learn to read their stress triggers & signs.
If they start to develop any clinical signs, it's best to jump on it earlier rather than later. However, in most cases, a vet won't start antibiotics until clinical signs have progressed, because of the reasons I explained earlier > abx target the secondary bacterial signs, not the actual virus itself, and they can disrupt their normal gut microbiome and/or contribute to abx resistance if given too often. Keep up to date with their vaccination schedule to ensure that their immune system is in the best place to fight infections.
In summary, a confident/brave/happy cat that can face little daily stressors head on + good nutritious diet + being on top of hygiene + vaccinations + a boosted immune system (give or take the last thing, because, science!) is the best combination for a cat to remain in a healthy, latent viral state.
So I know that's a tonne of reading, and if you've gotten this far, I appreciate it.
One last thing I wanted to mention.... you may have been following little Butterscotch aka Percy. He's 12 weeks old now from Nico's B-Litter. At 2 weeks old, I noticed his right eye was smaller than the left, it wasn't developing normally and for about a fortnight it was a white-glossy colour. At 4 weeks it started developing structures... a pupil and an iris began to form, but the structures were pointing downwards (ventrally). Now at 12 weeks, it doesn't appear to have any light reflex and we really aren't sure whether he can see shadows, or he might be completely blind in that eye. We initially thought it would be best to remove it to reduce risk of pain, increased pressure or the body rejecting it and not providing enough nutrition to the cells. However, over time, he doesn't appear to display any pain signs. It's not blinky or squinty. He doesn't paw at it. In fact, if you saw him from afar, he appears to see, run, play, jump and judge distances just like his siblings.
At first we (and the ophthalmologist) thought it was just a one-off congenital defect, random. And that still may be the case. But it is a possibility that Nico was harbouring FHV during the pregnancy (she didn't have clinical signs) and perhaps it was trans-placentally passed down causing an ocular defect... despite the evidence that steers toward the view that vertical transmission isn't seen in the field. None of the other kittens showed any defects. So we may never know whether it was a random occurrence or not. If we do a repeat mating with Nico, then this may reveal more with the offspring produced. We're undecided at this stage on whether to just raise these new generations cautiously and spay our current queens (Nico and Adelaide), or whether it will be okay to do a repeat mating. We'll be thinking some more on that over the next few months.
Oh, and here's some references to back up my rambling...