Fleas – Tanya's Comprehensive Guide to Feline Chronic Kidney Disease

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Overview

CKD cats are still prone to normal feline health issues, such as fleas.
Since many CKD cats are older, they may also suffer from arthritis or cognitive dysfunction (kitty Alzheimer’s or senility).
This page discusses these problems in light of the CKD diagnosis.
There is also a discussion about the vaccination of CKD cats.

Table of Contents

Flea Treatments

The flea found most frequently in homes is the cat flea, Ctenocephalides felis felis. Despite its name, it can also live on other animals in the household, such as dogs, and may also feed off humans.

US Centers for Disease Control and Prevention has a good overview of flea infestation and how to treat it.

The Importance of Flea Control

Fleas can make a cat uncomfortable, especially if they are allergic to flea bites, and can lead to tapeworm infestations.

Most worryingly, a severe infestation may lead to anaemia, which in the worst case can kill. Biology, treatment and control of flea and tick infestations (2009) Blagburn BL & Dryden MW Veterinary Clinics of North America. Small Animal Practice 39 pp1173-1200 says “Blood consumption by fleas can produce iron deficiency anemia and even death in heavy infestations.” Mar Vista Vet explains more about this and says that elderly cats (which most CKD cats are) who go outdoors are more at risk.

Anaemia from fleas is still a concern even if your CKD cat does not go outside, because CKD cats are prone to developing anaemia anyway because of the CKD. Flea-related anaemia on top of this could be very dangerous. Therefore any flea problems must be addressed.

Fleas: Lifecycle

In order to implement a proper flea eradication programme, it helps to understand the flea lifecycle.

The fleas in your home will be in one of four life stages:

eggs: not visible to the naked eye.
larvae: baby fleas, not visible to the naked eye. They feed on adult flea faeces.
pupae: the cocoon phase. These are roughly the size of a grain of salt.
flea: small, black and visible to the naked eye (though you may not necessarily notice them).

Fleas will lay their eggs on your cat’s body but the eggs will then fall onto bedding, carpets etc. where the first three stages of the lifecycle will occur. Any live fleas on your cat came from eggs laid in your soft furnishing and carpets 3-8 weeks ago. Therefore you must not only treat the cat, you must treat the environment, or you will never become flea-free because fleas will continue to hatch.

With a proper food supply (your cat’s blood), fleas usually live for 2-3 months, though they can live as long as nine months. Therefore it can take several months to completely eradicate fleas from your home. If you live in an area prone to fleas, it is wise to maintain a year round flea control programme.

Library of Congress explains more about the lifespan of the flea.

The Companion Animal Parasite Council has a diagram showing the lifecycle.

Fleas: Treatment Goals

In order to completely eradicate a flea infestation, products used for flea control in cats have the following goals:

Kill the fleas
Kill the grown fleas that are currently present. Medications used for this purpose are insecticides. They work in various ways, but they all kill fleas.

Kill the eggs, larvae and pupae
These medications stop the fleas from reproducing by interrupting the flea life cycle. Most products used for this purpose in cats are insect growth regulators (IGR). Most of them only stop the eggs and larvae, so any pupae present in your home at the time of treatment can still hatch as fleas. This can be a problem because, according to Biology, treatment and control of flea and tick infestations (2009) Blagburn BL & Dryden MW Veterinary Clinics of North America. Small Animal Practice 39 pp1173-1200, “Once the pupa has fully developed, the pre-emerged adult flea within the cocoon can be stimulated to emerge from the cocoon by physical pressure, carbon dioxide, and heat. If the pre-emerged adult does not receive an emergence stimulus, it may remain quiescent in the cocoon for several weeks or months until a suitable host arrives.” Eventually, however, the cycle should be stopped even if you only kill the eggs, larvae and fleas.

Fleas: Treating the Cat

You need to treat your cat first, to kill any fleas already on him/her and make him/her more comfortable. You must treat all your animals, not only your cat(s). Check with your vet that the product you plan to use is suitable for the species in question. Never use a product intended for dogs on your cats without checking with your vet first.

Treating CKD Cats

I understand that it can be very stressful making the decision to use flea treatments on a CKD cat. You may be particularly concerned if you look at many product inserts and find that they say that they should not be used on sick cats.

In retrospect, I used to be rather cavalier in my approach to flea treatments because fleas have never been a big problem for us. I honestly cannot remember the last time we had fleas, but it might have been 2003. Certainly I have never needed to use any product on an ongoing basis, and have never had to treat my current cats (aged eight and nine) for fleas, even though they both go outdoors (in my walled garden).

Since we get very infrequent flea infestations, the last time we had them I found that I did not have to apply flea products directly to my sick cat. Instead, I applied the flea treatment only to my other cats, and used a flea comb on all of them every day, including the sick cat, as well as treating the environment (see below). I did this using Frontline for the healthy cats and Acclaim for the environment, and we did get rid of the fleas.

However, I have heard from people who have terrible problems controlling flea infestations, and I even heard from one person whose cat (who had no other health issues) died from anaemia caused by fleas. So I do now believe that you need to do all you can to eradicate fleas from your home as quickly as possible. Therefore these days I would opt to use a flea treatment on all my cats, sick or otherwise, at least for the first month or so.

Most people on Tanya’s CKD Support Group have used flea products on their CKD cats with no problems. Any reactions have usually been mild and transient and most importantly, the flea problem has been resolved and their cat protected from the risks associated with fleas, particularly anaemia.

Even if you normally use over the counter treatments for fleas, if you have a CKD cat, I would strongly advise that you obtain your vet’s advice on the best product to use on your cat.

Flea Comb

Regardless of which flea killing product you use, you should also buy a flea comb and use it daily. If you are using a flea killing product, you should soon find that you are only removing dead fleas, but to start with you will usually be combing out live fleas. On the rare occasions that we have fleas, I usually have a glass of water next to me and I deposit the fleas in it, or I squash them on a tissue.

The little dark specks you can see in your cat’s coat are not fleas, but instead are flea dirt. Biology, treatment and control of flea and tick infestations (2009) Blagburn BL & Dryden MW Veterinary Clinics of North America. Small Animal Practice 39 pp1173-1200 explains “While feeding, female cat fleas excrete large quantities of incompletely digested blood, which dries within minutes into reddish-black fecal pellets or tubular coils that are often called ‘‘flea dirt’’ or ‘‘frass.’’”

Flea Shampoo

Some people use flea shampoos on their cats. These can help to kill fleas present on your cat but will not kill eggs, larvae or pupae.

Since most cats find baths stressful, I do not think I would want to put a CKD cat through this, but if you do so, I know that some people active in rescue find Dawn dish soap is gentle enough to bathe kittens with fleas. Alternatively you could obtain a suitable shampoo from your vet.

Fleas: Medications

There is a wide variety of medications available, in both oral form (pills) and topical form (applied to the skin). Many of the topicals are spot on treatments which are usually applied to the nape of the neck (where the cat cannot lick it), which is much easier than trying to apply a treatment to your cat’s entire body.

Many products combine two forms of flea control — an insecticide to kill adult fleas and an insect growth regulator to stop the flea lifecycle — so as to maximise your chances of success.

Which product to choose depends upon many factors, such as which products are available where you live, whether you have used them before with success, which method of administration you prefer, how long the product lasts, and of course the cost.

Below I aim to give an overview of the main flea products available for cats in most parts of the world, though the list is not exhaustive. If your cat has a poor reaction to one product, it can help to know which other products contain the same ingredient so you can avoid them too.

Don’t forget, you must treat all your animals, not only your cat(s). Check with your vet that the product you plan to use is suitable for the species in question. Never use a product intended for dogs on your cats without checking with your vet first.

Mar Vista Vet has excellent detailed information on the many flea products available and how they work.

Fleas: Resistance

I regularly hear from people who believe their cat has developed resistance to flea medications. Although flea resistance is certainly possible, before you fear the worst you must consider whether there might be another explanation. Fleas persist but reason isn’t resistance (2010) Veterinary Practice News quotes Dr M Dryden, an expert in cat fleas known as “Dr Flea”: ““What clients are likely seeing are new fleas from the environment as opposed to fleas surviving after a proper spot-on application,” says Michael Dryden, DVM, Ph.D., a professor of veterinary parasitology in Kansas State University’s Department of Diagnostic Medicine and Pathobiology. “I have investigated homes that by owner description sound like there could be a resistance problem but found, when I looked closer, there was always a reason for the failure. None was ever resistance.””

Insecticide resistance to fleas (2016) Rust MK Insects 7(1) p10 discusses the effectiveness of flea treatments and reports of resistance, but also states that “The initial response to product failures by practitioners and clients is often to attribute them to insecticide resistance. However, in recent years many of these failures have been ascribed to operational factors. These include the failure to properly treat all pets in a household, to follow label instructions, to continue treatments in winter months, and to properly apply the product to the animal.”

These failures may arise because of a lack of understanding of the flea lifecycle. Insecticide/acaricide resistance in fleas and ticks infesting dogs and cats (2014) Coles TB & Dryden MW Parasites and Vectors 7(8) says “It can be difficult, if not impossible at times, for practitioners to differentiate between parasite resistance and other causes of inefficacy due to a multitude of environmental, host, and client variables. First, inconsistencies in client compliance must be considered. Second, particularly with fleas, how long have insecticide treatments been ongoing? This is important given the well-known 2 to 3 month flea emergence pattern that occurs following initiation of topical and systemic treatments. Flea eggs deposited in the premises before treatment will continue to develop and newly emergent fleas will continue to populate the home for at least a couple of months posttreatment, regardless of the type of pet treatment. Depending on the number of eggs and rate of larval survivability, the problem may very well get worse before it improves.”

In fact, you may be surprised by what is actually meant by resistance. Fleas persist but reason isn’t resistance (2010) Veterinary Practice News: ““When parasitologists talk about resistance they do not necessarily mean a total lack of efficacy,” says Patrick Meeus, DVM, Ph.D., Dipl. EVPC, the vice president of the American Association of Veterinary Parasitologists. “Resistance [occurs] only if efficacy is less than when the product was first launched or below the 90 percent efficacy levels typically required by government agencies to get a claim in the first place.”” So resistance is only deemed to be present if the product has as little as 89% effectiveness, which means that a product that did not work for 10 out of 100 cats (10%) would still not be deemed to be a product to which fleas have developed resistance. Not much comfort if your cat is one of those 10%.

Resistance in this sense has been found in some strains of fleas. Insecticide/acaricide resistance in fleas and ticks infesting dogs and cats (2014) Coles TB & Dryden MW Parasites and Vectors 7(8) says “Search of the Arthropod Pesticide Resistance Database (APRD), which uses a qualifying RR of ≥10 to be considered resistant, revealed that for fleas of interest to veterinarians who treat dogs and cats there were 28 resistance reports for C. felis.” However, it goes on to say “None of these APRD-referenced reports involve resistance to chemicals currently labeled for flea control on dogs or cats in the United States.”

Still, there have been reports of fleas in California and Florida developing resistance to certain flea treatments. Biology, treatment and control of flea and tick infestations (2009) Blagburn BL & Dryden MW Veterinary Clinics of North America. Small Animal Practice 39 pp1173-1200 says of insect growth regulators “when used in combination with adulticidal compounds, the likelihood of developing resistance is diminished considerably, because the flea life cycle is being disrupted at different points and by entirely different mechanisms.” Therefore you may wish to choose a product that contains both an adult flea killer and an insect growth regulator. I discuss below which treatments contain which type of medication.

Capstar (Nitenpyram)

Capstar is an oral (pill) insecticide which kills fleas very quickly. It is considered safe enough for very young kittens.

Capstar is available over the counter in 11.4mg and 57mg size tablets, but the latter size is for use in large dogs. The usual dose for cats over 2lb in weight is one 11.4mg tablet per day. It starts killing fleas within thirty minutes.

Many people on Tanya’s CKD Support Group use this as the initial attack rather than a flea shampoo. Capstar appears to be very effective, with people reporting they can see dead fleas falling off their cat within an hour.

Capstar can be given daily if necessary, but it only kills adult fleas so you will also need to treat the environment in order to kill the eggs and larvae. You may also wish to introduce a longer lasting treatment in order to avoid daily pilling.

Biology, treatment and control of flea and tick infestations (2009) Blagburn BL & Dryden MW Veterinary Clinics of North America. Small Animal Practice 39 pp1173-1200 has some information about Capstar on page 1191.

Frontline: Fipronil and Methoprene or Fipronil, Methoprene and Pyriproxyfen

Frontline is a flea treatment that has been around for a long time. The original Frontline contained fipronil, a flea killing insecticide (fipronil is now also becoming available as a generic medication). The original Frontline was superseded by Frontline Plus and Frontline Gold. These later formulations also contain insect growth regulators, as follows:

	Flea Killer	Insect Growth Regulators
Product	Fipronil	Methoprene	Pyriproxyfen
Frontline	•
Frontline Plus	•	•
Frontline Gold	•	•	•

Frontline will kill adult fleas. Frontline Plus and Frontline Gold both kill adult fleas, and the insect growth regulators they contain will also kill eggs and larvae.

These products are normally applied once a month as a “spot on” to the neck, though there is also a Frontline spray (fipronil only) for the entire body. Frontline Plus and Gold kill adult fleas within twelve hours and last for a month.

Frontline Plus is available without a prescription, but Frontline Gold is a prescription medication.

Revolution or Stronghold: Selamectin (Plus Versions Also With Sarolaner)

Revolution is a prescription product known as Stronghold in the UK. Its active ingredient, selamectin, is a flea killer which also kills larvae and stops flea eggs hatching. These products are normally applied once a month as a “spot on” to the neck and begin working within 24 hours.

In 2017 the manufacturer announced that a new version, Stronghold Plus, has been approved in Europe. It was also launched in the USA as Revolution Plus. This version contains both selamectin and sarolaner, another insecticide, and the combined product offers protection against ticks and heartworm as well as fleas. Stronghold Plus apparently lasts for five weeks. The European Medicines Agency (2017) has an overview of Stronghold Plus.

The European Medicines Agency public assessment report (2017) says “Stronghold Plus must not be used in cats suffering from other diseases or in cats that are weak and underweight (for their age).”

The US Food and Drug Administration reports that some animals given treatments in the isoxazoline class (which includes Revolution Plus) “have experienced adverse events such as muscle tremors, ataxia, and seizures.” It is my understanding that the issues arose with Bravecto, and there have been no reports to date of similar problems with Revolution Plus, but the FDA has ordered the manufacturer to include new information on the label highlighting the potential for neurologic events.

Several members of Tanya’s Support Group have used Revolution and most of them had no problems. One member has used Stronghold Plus with no problems.

Bravecto (Fluralaner)

Fluralaner is a newer topical flea treatment made by Merck Animal Health with the trade name of Bravecto. It apparently kills fleas within eight hours and according to A single topical fluralaner application to cats and to dogs controls fleas for 12 weeks in a simulated home environment (2018) Ranjan S, Young D & Sun F Parasites and Vectors 11(385), it lasts for twelve weeks. It also kills ticks.

The US Food and Drug Administration reports that some animals given treatments in the isoxazoline class (which includes Bravecto) “have experienced adverse events such as muscle tremors, ataxia, and seizures.” It also states “these products continue to be safe and effective for the majority of animals” but adds that vets should only prescribe them on an individual basis after carefully reviewing the animal’s medical history.

I have not heard from anybody who has used Bravecto yet.

Advantage: Imidacloprid and Pyriproxyfen or Imidacloprid and Moxidectin

The original Advantage contained imidacloprid, an insecticide which targets adult fleas. Imidacloprid is also found in Seresto collars.

Advantage II superseded the original version of Advantage. Advantage II still contains imidacloprid to kill adult fleas, but it also contains pyriproxyfen, an insect growth regulator which works on eggs and larvae. Pyriproxyfen is also found in Frontline Gold, Vectra and Catego. Advantage II is a spot on product which starts working within twelve hours and lasts for thirty days. It is available over the counter in the USA.

Advantage Multi (Advocate) is a combination of imidacloprid and moxidectin (which kills other parasites, such as worms). It is a spot on product which provides protection for a month. Drugs has some information about it.

Prinovox is another combination of imidacloprid and moxidectin made by Virbac which is available in the UK. It is also a spot on product which provides protection for a month.

Vectra: Dinotefuran and Pyriproxyfen

Vectra contains an insecticide called dinotefuran (also found in Catego) to kill adult fleas, together with an insect growth regulator called pyriproxyfen (pyriproxyfen is also found in Frontline Gold, Advantage II and Catego).

Like other insect growth regulators, pyriproxyfen works on eggs and larvae, but Biology, treatment and control of flea and tick infestations (2009) Blagburn BL & Dryden MW Veterinary Clinics of North America. Small Animal Practice 39 pp1173-1200 says “Recent products that combine dinotefuran and pyriproxyfen also carry label claims against pharate (early) pupae.”

Vectra is a spot on product that begins working within six hours and lasts for a month.

Catego: Dinotefuran, Fipronil and Pyriproxyfen

Catego is a newer product (released in the USA in late 2016), though its ingredients are not new. It contains dinotefuran (also found in Vectra) and fipronil (also found in Frontline), both insecticides that kill adult fleas, together with an insect growth regulator called pyriproxyfen (also found in Frontline Gold, Vectra and Advantage II).

Catego is a spot on treatment that begins working within six hours and lasts for one month.

I haven’t heard from anybody who has used Catego as yet.

Cheristin: Spinetoram

Cheristin is an over the counter treatment which contains an insecticide called spinetoram which kills adult fleas.

Cheristin is a spot on treatment that begins working within 30 minutes and lasts for a month.

Since Cheristin only kills adult fleas, you will usually also need to take other steps in order to kill the eggs and larvae.

Pet Place has some information about Cheristin.

Activyl: Indoxacarb

Activyl contains an insecticide called indoxacarb that kills adult fleas but also eggs, larvae and pupae. It is a spot on product that begins killing fleas within twelve hours and lasts for one month.

I have heard from a couple of people who have used it on their CKD cats with no problems.

Comfortis: Spinosad

Comfortis is a fleakiller called spinosad which works by paralysis.

Comfortis comes in pill form, though the pill is quite large so you may need to give it in pieces. It begins working within thirty minutes and lasts for a month, though the manufacturer recommends at least three months of treatment.

Since Comfortis only kills adult fleas, you will usually also need to take other steps in order to kill the eggs and larvae.

I heard from a couple of people who have used it on their CKD cats with no problems, though a couple of others have seen vomiting after giving it.

Mar Vista Vet has some information about Comfortis.

Credelio: Lotilaner

Credelio is a flea treatment available in the UK. It contains lotilaner, and comes as a very small flavoured tablet that starts working within twelve hours and lasts for a month. The tabelt must be given with food or within 30 minutes of feeding for it to work properly.

Since Credelio only kills adult fleas, you may need to take other steps in order to kill the eggs and larvae.

The UK National Office of Animal Health has some information about Credelio.

I have heard from one person so far in the UK who has used Credelio on their CKD cat with no problems.

Seresto: Imidacloprid and Flumethrin

Seresto is a flea collar which contains imidacloprid, an insecticide which targets adult fleas (this is also found in Advantage), and flumethrin, which has some insecticidal properties but which is primarily for the treatment of ticks. It starts working within 24 hours and is effective against fleas and ticks for up to eight months.

Since it only kills adult fleas, you may need to take other steps in order to kill the eggs and larvae. However, Efficacy of an imidacloprid/flumethrin collar against flea and ticks on cats (2012) Stanneck D, Kruedewagen EM, Fourie JJ, Horak IG, Davis W & Krieger KJ Parasites and Vectors 5 p82 reports on the efficacy of the Seresto collar, saying “Collaring during late winter or spring will not only get rid of any existing flea population, but will also eliminate fleas that have over-wintered as pupae and have now accessed the cats in spring. Thereafter the collars will protect cats from re-infestation until the end of the flea season. Equally important, residues of the imidacloprid component of the collars on bedding or in other resting places of treated cats will prevent any flea larvae that do hatch from developing into adults.”

A few members of Tanya’s CKD Support Group who live in places where fleas are an issue year round have found the collars effective with no side effects.

One member of the group was advised by her vet to put a flea collar in her vacuum cleaner’s dust bag, to help kill any fleas vacuumed up. You would need to check whether this is safe for your particular vacuum cleaner.

Drugs has some information about Seresto collars.

Pet Place discusses Seresto collars.

Fleas: Treating the Environment

It is important to treat the environment as well as your cat in order to get completely rid of the problem. Ridding your home of fleas (1998) Potter MF University of Kentucky College of Agriculture says “If you neglect to treat the pet’s environment (the premises), you will miss more than 90% of the developing flea population — the eggs, larvae and pupae.”

Fortunately many of the medications available for cats do kill eggs and larvae in the environment as well as adult fleas on the cat, and one or two also kill pupae. However, in order to get rid of the fleas as quickly as possible, it is wise to opt for a multi-pronged approach as follows:

Vacuum Daily

You must vacuum daily, especially your carpets and anywhere where your cat spends a lot of time, such as on a sofa or in a cat bed.

Biology, treatment and control of flea and tick infestations (2009) Blagburn BL & Dryden MW Veterinary Clinics of North America. Small Animal Practice 39 pp1173-1200 says “In addition, cocooned pupae at the upper levels of the carpet can also be affected. The vibration also stimulates adult fleas to emerge from their cocoons so that they can be collected in the vacuum machine. Therefore frequent vacuuming, during a flea infestation, can reduce the overall flea burden in the home. It should be ensured that vacuum bags are disposed of properly, to prevent recolonization of the home with flea stages previously removed by vacuuming.”

Wash Bedding

Anything washable, such as your cat’s bed, throws etc., must be washed regularly.

Room Sprays and Powders

If you have a severe flea infestation, you may wish to use room sprays or powders to kill eggs and larvae in the environment. Some of these do contain ingredients that can be toxic to cats, so be very careful.

Advantage

Advantage is available as a carpet spray and also as a crevice spray. Like Advantage for cats, it contains imidacloprid together with two other ingredients.

Indorex

Indorex is a popular choice in the UK. It contains an insecticide called permethrin which kills adult fleas, together with pyriproxyfen, an insect growth regulator also found in a number of cat spot on products which works on eggs and larvae, and piperonyl butoxide, which strengthens the effect of permethrin.

Unfortunately permethrin is toxic to cats (see below), so although it is safe in the amounts used, especially once it is dry, you must be very cautious and never allow your cat back in the room until the spray has completely dried.

Acclaim

Acclaim is a room spray made by Vet-kem which contains permethrin, which kills adult fleas, and methoprene (also found in Frontline II), an insect growth regulator which works on eggs and larvae.

Permethrin is toxic to cats (see below), but the manufacturer claims that when used as directed, Acclaim is safe for cats. You should not let your cats anywhere near where you have sprayed until it is dry.

I have used Acclaim without any problems, but only occasionally.

Outside Treatments

if your cat goes outside, you may need to treat your yard or garden too, especially if you have wildlife outside. Insecticide resistance to fleas (2016) Rust MK Insects 7(1) p10 says “Feral animals such as opossums and raccoons may serve as an outdoor reservoir and re-infestation of pets.”

Advantage is available as a Home and Yard treatment.

Fleas: Treatment Cautions

It is amazing how many treatments are promoted for fleas, some of which are somewhat questionable, whilst others can be downright dangerous.

Products for Dogs

Some people use flea treatments intended for dogs, often because they think it will work out cheaper. This can be risky because some flea products for dogs contain permethrins or pyrethrins, which are toxic to cats.

It can also be tricky getting the dose of a dog-sized product right for cats, who are often much smaller than dogs.

Sprinkled Products

These are powdered treatments that are sprinkled around the home and which help to kill fleas. They may cause lung irritation, so a mask must be worn when applying them.

Borax

Some people have tried borax-based products. Borax works by desiccation, i.e. it dries out the flea larvae. It does not kill flea eggs.

You do not want your cats exposed to borax, e.g. if they get it on their paws and lick it, so it should be applied to your carpets and removed while your cat is absent. You brush it into the carpet, wait an hour or two and then vacuum it up.

Because borax is a powder, it can be difficult to vacuum it up properly. Fleabusters Rx For Fleas is a borax-based product which is very finely milled, so less is needed, and it is designed to sink deep into carpets where it can kill flea larvae but not be too close to your cat.

Diatomaceous Earth

Diatomaceous earth (DE) is extremely fine and sharp silica powder. It is actually formed from the fossilised remains of microscopic animals called diatoms.

DE is sometimes used to help with fleas by sprinkling it around the cat’s bedding and into carpets etc. It kills fleas by drying them out, though its sharp edges also contribute. Although it does kill fleas, as I understand it, it doesn’t kills eggs, larvae or pupae.

There are two main types of DE, pool grade and food grade. Pool grade should only be used for pool filtration (because of the way it is processed, it will not work for fleas).

To be labelled food grade, the diatomaceous earth cannot contain more than 10mg/kg of arsenic or lead. Contrary to popular opinion, food grade DE is not normally used in human foods (rather, it is permitted for pest control in grains) but animal food can contain up to 2% food grade DE.

Is ‘food grade’ diatomaceous earth okay for pest control? (2017) National Pesticide Information Center recommends using products with pesticide labels rather than food grade DE for pest control. However, Diatomaceous earth (2006) Pest Press Arizona Cooperative Extension University of Arizona 7 pp1-2 states that pesticidal versions of DE may also contain insecticides such as pyrethrin, whereas food grade DE only contains DE, and suggests using food grade.

Some people sprinkle DE on their cat’s coat. DE can be a lung irritant, so you are supposed to wear a mask when using DE (see Center for Disease Control and Prevention). Therefore I would not recommend sprinkling DE on your cat’s coat.

Others sprinkle it on their carpets, brush it in, let it sit for a few hours, then vacuum it out again, similar to using borax-based products.

I am not a big fan of this sort of product because of the potential for causing lung problems, but some people do use them and like them. I think if I were to use such a product, I would probably use the Fleabusters borax-based product.

Permethrins or Pyrethrins

These are insecticides which can be safe for cats in small amounts but which are toxic to cats in larger amounts.

Permethrin spot on products can kill cats (2013) UK Veterinary Medicines Directorate has a list of products available in the UK which may cause problems for cats and says “These products are intended for the treatment of fleas and ticks in dogs only. They contain permethrin, a substance that is safe for dogs but causes a toxic reaction in cats when present in spot on products, due to its concentration. Cats treated with even small amounts of spot on products containing permethrin, or allowed to groom dogs treated with any of the products in the list above, can develop nervous signs such as depression, drooling, tremors, seizures, vomiting and staggering, and can die.”

Just because a product is not on this list does not mean it is safe for cats — check the ingredients first.

International Cat Care explains more about permethrin toxicity and how to treat it.

Flea Collars

Although Seresto collars are usually safe, other flea collars can be problematic for cats. One problem is the active ingredients used. In 2016 the US Food and Drug Administration agreed with some collar manufacturers that they would stop selling flea collars containing one such ingredient, propoxur, because of the risks to children.

Many over the counter flea collars for cats contain permethrin, which is toxic to cats in large amounts. International Cat Care has a list of such collars in the UK and says “While the concentration of permethrin in these collars is much lower, International Cat Care believes there are much safer and far more effective flea control methods than using collars containing permethrin on cats. While the concentration of permethrin in the collar alone should not cause problems, if the cat is also exposed to other sources of permethrin, the collar could contribute to poisoning.”

Environmental and lifestyle risk factors for oral squamous cell carcinoma in domestic cats (2003) Bertone ER, Snyder LA & Moore AS Journal of Veterinary Internal Medicine 17(4) found that cats wearing flea collars had five times the risk of developing squamous cell carcinoma (an oral cancer that is very difficult to treat) of cats that didn’t wear such collars.

Garlic

You may read that adding garlic to your cat’s food can help control fleas. However, Fleas infesting pets and homes (2003) Dryden MW, Payne P & Zurek L Kansas State University states “use of brewers’ yeast, garlic, B-complex vitamins and elemental sulfur products as flea repellents is common practice. Controlled studies have shown that these materials are not effective flea repellents.”

In any event, garlic may cause Heinz body anaemia in cats (see Which Foods to Feed), so I would not recommend this treatment.

Essential Oils

Products containing essential oils should also be avoided — they are toxic to cats, who lack the pathways to metabolise them.

Cognitive Dysfunction Syndrome (Senility or Feline Alzheimer’s)

Cognitive dysfunction syndrome (FCD) is the name given to the signs of aging seen in cats which are similar to those seen in humans with dementia. The cause is not known, but reduced blood flow in the brain and increased free radicals may be factors.

Cognitive dysfunction in cats: clinical assessment and management (2011) Gunn-Moore DA Topics in Companion Animal Medicine 26(1) pp17-24 has a helpful overview of cognitive dysfunction in cats.

Cognitive dysfunction (2013) Gruen ME Clinician’s Brief Dec 2013 pp13-16 has an overview of cognitive dysfunction in cats.

Survey of risk factors and frequency of clinical signs observed with feline cognitive dysfunction syndrome (2022) MacQuiddy B, Moreno J, Frank J & McGrath S Journal of Feline Medicine and Surgery OnlineFirst May 2022 found that living in a rural environment appeared to reduce the risk of developing FCD.

International Cat Care has some information about senility in cats.

Pet Place has an overview of cognitive dysfunction.

Cornell University College of Veterinary Medicine discusses cognitive dysfunction.

Cognitive Dysfunction Syndrome: Frequency

Cognitive dysfunction is very common in older cats: Increased vocalisations in elderly cats (2015) Gunn-Moore DA European Journal of Companion Animal Practice 25(3) pp20-29 states “Approximately 30% of pet cats aged 11-14 years develop at least one age-associated behavioural problem; this increases to over 50% for cats aged ≥15 years.”

Cognitive Dysfunction Syndrome: Symptoms

Symptoms are sometimes referred to as DISHA. This stands for:

Disorientation
Interaction changes
Sleep changes
House soiling
Activity changes

Cognitive dysfunction syndrome Ohio State University College of Veterinary Medicine Indoor Cat Initiative explains more about these symptoms.

Survey of risk factors and frequency of clinical signs observed with feline cognitive dysfunction syndrome (2022) MacQuiddy B, Moreno J, Frank J & McGrath S Journal of Feline Medicine and Surgery OnlineFirst May 2022 found that symptoms seen in cats with FCD included howling (40%), nighttime restlessness (30.1%), anxiety, overgrooming and housesoiling.

Wandering around the house howling, especially at night, is a common symptom of disorientation, activity and sleep changes. Increased vocalisations in elderly cats (2015) Gunn-Moore DA European Journal of Companion Animal Practice 25(3) pp20-29 states “The behavioural changes reported most commonly are increased vocalisation (especially at night), and inappropriate elimination.” My vet told me that sometimes old cats wake up and feel a little confused, are not sure where they are, so they howl for reassurance; once they hear your voice, they feel comforted and will usually stop howling. There are a number of other possible causes of howling in CKD cats, see Index of Symptoms and Treatments.

The American Association of Feline Practitioners (2009) Pittari J, Rodan I, Beekman G, Gunn-Moore D, Polzin D, Taboada J, Tuzio H & Zoran D Journal of Feline Medicine & Surgery 11 pp763-778 has a mobility/cognitive dysfunction questionnaire (Table 3 on page 773).

Cognitive Dysfunction Syndrome: Treatments

Cognitive dysfunction syndrome cannot be cured but it can be managed. The mainstays of management are nutritional supplements and medications. Since cats like routine, try to keep their routine regular if possible

Management of dogs and cats with cognitive dysfunction (2017) Seibert l Today’s Veterinary Practice 7(5) discusses possible treatments for CDS in cats.

Cognitive Dysfunction Syndrome: Nutritional Supplements

There are a number of nutritional supplements available which are thought to help with cognitive dysfunction syndrome. These usually contain essential fatty acids and antioxidants (which help mop up free radicals). Be careful which you choose because many of these products are designed for dogs and the ingredients are not always suitable for cats.

Cognitive Dysfunction Syndrome: Vitamin B12 (Methylcobalamin)

In humans, a lack of vitamin B12 has been associated with cognitive dysfunction. Supplementing v itamin B12 in the form of methylcobalamin is therefore worth considering.

Cognitive Dysfunction Syndrome: Aktivait

Aktivait Cat is a nutraceutical containing essential fatty acids and antioxidants which has been found in one trial to help dogs with cognitive dysfunction. It contains various ingredients, including essential fatty acids, vitamin E and co-enzyme Q10 but it also contains phospholipids and vitamin C, which may not be appropriate for CKD cats. Be guided by your vet.

Make sure you only use Aktivait Cat because the canine version contains alpha lipoic acid, which is safe for dogs but thought to be toxic to cats,

Cognitive Dysfunction Syndrome: S-AdenosylMethionine (SAMe)

S-adenosylmethionine (SAMe) is an antioxidant which is also used to treat cats with liver disease and which may be of some help for cats with arthritis. Brand names include Novifit and Denosyl.

Cognitive dysfunction in cats: clinical assessment and management (2011) Gunn-Moore DA Topics in Companion Animal Medicine 26(1) pp17-24 says “Although S-adenosyl-l-methionine has not been studied for the treatment of CDS in cats, it is known to be safe in this species and may be worth considering for the management of feline dementia.”

Cognitive Dysfunction Syndrome: Medications

Cognitive Dysfunction Syndrome: Selegiline (Anipryl)

Selegeline or selegiline (Anipryl) is sometimes used to treat cognitive dysfunction in dogs and also appears to be effective in cats. Retrospective study on the use of selegiline (Selgian) in cats (1999) Dehasse J Presentation to the American Veterinary Society of Animal Behavior reports on the effect of selegiline in cats.

Plumb’s Veterinary Drug Handbook states that a possible dose is 0.25 — 1 mg/kg orally once daily.

Mar Vista Vet explains more about how selegiline works, and mentions that it may increase the risk of serotonin syndrome, so check with your vet before using selegeline and mirtazapine.

Pet Place also has information about selegiline use in animals.

The Cat Site talks about the experiences of one cat who participated in a study into the use of selegiline in cats.

Vaccinations

Vaccinations protect cats from certain infectious diseases. They do this by stimulating the cat’s immune system to develop antibodies towards the disease, so the cat’s immune system will try to fight off the disease should it be exposed to it in the future. The immune response to vaccination: a brief review (2013) Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 Supp pp1-3 explains more about how vaccines protect cats from infection.

Kittens are normally given a series of vaccinations, and then cats are revaccinated throughout their lives, with the frequency varying depending upon the type of vaccine used and the legal requirements of the area where the cat is located.

The American Veterinary Medical Association explains more about how vaccinations work and the benefits they offer.

Cornell University College of Veterinary Medicine explains the benefits and risks of vaccinations.

2013 AAFP Feline Vaccination Advisory Panel report (2013) Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 pp785-808 are an earlier version of the guidelines.

Guidelines for the vaccination of dogs and cats compiled by the Vaccination Guidelines Group (VGG) of the World Small Animal Veterinary Association (WSAVA) (2016) Day MJ, Horzinek MC, Schultz RD & Squires RA Journal of Small Animal Practice 57 ppE1-E45 also offers detailed vaccination guidelines.

The 2020 guidelines say the 2013 and 2016 guidelines “should still be considered relevant and actionable complements to the 2020 guidelines.”

This section explains more about core vaccinations and their benefits and risks, particularly for CKD cats.

Vaccinations: Types

There are a number of vaccinations available for cats. Cornell University College of Veterinary Medicine provides an overview of the main feline vaccines, including non-core vaccines.

The following are the core vaccines which are usually offered to CKD cats (rabies is not offered in the UK unless the cat is going abroad):

Vaccinations: FVRCP

These are the core vaccinations given to kittens, and then topped up over the course of the cat’s life.

FVRCP vaccinates the cat against three feline diseases. FVRCP stands for:

Initial	Refers To	Notes
F	Feline
VR	Viral Rhinotracheitis	Caused by the feline herpes virus (FHV-1)
C	Calicivirus (FCV)
P	Panleukopaenia (FVP)	Also known as distemper or parvovirus

The FVRCP vaccine was usually given several times to kittens a few weeks apart; it was then given once yearly in countries such as the UK and once every three years in countries such as the USA (see Frequency). However, 2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265 now advise that following the initial series of vaccinations given to kittens, the first top up should be given at six months of age, then three yearly thereafter. The six monthly shot may not be necessary if you are using an intranasal vaccine, but annual vaccination will be required.

Viral Rhinotracheitis and Calicivirus

Viral rhinotracheitis (which is caused by the feline herpes virus) and calicivirus are both upper respiratory tract viral infections. In the UK they are sometimes colloquially referred to as “cat flu.”

This vaccine can be helpful against these viruses, though may not bestow complete immunity. Cornell University College of Veterinary Medicine says “Protection induced by the currently available vaccines minimizes the severity of disease, but does not prevent disease in all cats.” Two of my cats who had been vaccinated did develop upper respiratory tract infections at different times and were thoroughly miserable. However, their illnesses lasted less time and were less severe than that developed by the rescue cat I had just adopted who had not yet finished his course of vaccinations.

Disease information fact sheet feline herpesvirus 1 2013 Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 Supp pp1-3 has an overview of the feline herpesvirus.

Disease information fact sheet felinecalicivirus 2013 Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 Supp pp1-3 has an overview of the feline calicivirus.

Vaccination of cats against infectious upper respiratory disease (2013) Ford RB Today’s Veterinary Practice Nov/Dec 2013 explains more about feline upper respiratory viruses and vaccines. Some of the photos of infected cats should give you pause for thought if you are opposed to vaccinations.

Panleukopaenia (FPV)

Panleukopenia is also known as distemper. It is a nasty disease which is often fatal, particularly in kittens. Fortunately it is much less common since vaccination was introduced (the vaccines are highly effective), but since it can survive in the environment for years, unvaccinated cats may be at risk.

Disease information fact sheet: feline panleukopenia 2013 Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 Supp pp1-3 has an overview of the feline panleukopenia virus.

Feline panleukopenia guidelines (2015) Hartmann K European Advisory Board on Cat Diseases has some information on panleukopenia.

Rabies

Rabies is a serious disease that can kill both cats and humans. Therefore the rabies vaccine is a legal requirement in many countries throughout the world. It is not given routinely in the UK, where rabies does not exist, though it may be given there to cats who travel outside the UK (my cats had to have it before they could fly to the USA).

Disease information fact sheet rabies 2013 Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 Supp pp1-2 has an overview of the rabies virus.

Vaccinations: Formulations

There are three main forms of vaccine available:

inactivated (killed)
modified live (attenuated)
recombinant

As you might expect, a killed virus contains a dead form of the virus, so it will also contain an adjuvant to make it work. The adjuvant is added to create inflammation and thus stimulate an immune response to the vaccine. Adjuvants and vaccines Center for Disease Control and Prevention explains more about adjuvants. Modified live and recombinant vaccines do not contain adjuvants.

Unfortunately, in cats it appears that the use of vaccines containing adjuvants may result in a higher risk of developing a form of cancer known as FISS or feline injection site sarcoma (previously known as VAS, or vaccine-associated sarcoma). Veterinary Partner says that the adjuvant “holds the virus in the area of the vaccination for a couple of weeks so it can be released slowly, allowing immune stimulation to take place over a longer time period. This kind of stimulation can lead to local inflammation in the area of vaccination and one theory is that this inflammation is what leads to precancerous changes in the local cells. Indeed, some fibrosarcomas have been found to have vaccine adjuvant embedded within them.”

However, 2013 AAFP Feline Vaccination Advisory Panel report 2013 Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 pp785-808 say “Although initial reports linked development of sarcomas at vaccination sites with the use of inactivated rabies or FeLV vaccines, and aluminum-based adjuvants, more recent studies found no relationship between vaccine type, brand or use of inactivated versus modified-live vaccines and the risk of subsequent sarcoma formation.”

2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265 state “the Task Force believes there is currently insufficient research to justify recommending a single vaccine type.”

Nevertheless, Vaccination of cats against infectious upper respiratory disease (2013) Ford MB Today’s Veterinary Practice Nov/Dec 2013 pp57-61 says “Modified-live virus (nonadjuvanted) vaccine is recommended over killed virus products for routine use. Use of killed (adjuvanted) virus vaccine is reserved for use in pregnant queens, retrovirus positive cats, or in high-density populations, where there is minimal evidence of respiratory disease.”

Pet Place discusses which vaccine to choose.

Vaccinations: Benefits and Risks

The main benefit, of course, is that the cat is protected against illnesses that at best can make him/her very poorly and at worst could kill.

Two disadvantages of vaccination are the cost and, the fact that some cats may be under the weather for a few days after receiving vaccinations. 2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265 say “The most commonly reported vaccine reactions are lethargy, anorexia and fever for a few days after vaccination, or local inflammation at the site of injection.” However, I would say this small risk of being under the weather for a few days is worth it for the protection which vaccinations bring.

Other potential risks are as follows:

Vaccinations: Link to CKD

In 2002 a tentative connection between feline vaccinations and CKD was mooted. The connection arises because feline vaccines are grown on kidney cells known as Crandell Reese Feline Kidney (CRFK) cells. It has long been known that growing the vaccines in this way produces some unidentified antibodies in addition to those required for the vaccine, but it was only discovered in 2002 that the unidentified antibodies were to renal tissue. These additional antibodies occur in all modified live or killed vaccines, but do not occur with intranasal vaccines. In the UK, live vaccines are usually used.

Investigation of the induction of antibodies against Crandell-Rees feline kidney cell lysates and feline renal cell lysates after parenteral administration of vaccines against feline viral rhinotracheitis, calicivirus, and panleukopenia in cats (2005) Lappin MR, Jensen WA, Jensen TD, Basaraba RJ, Brown CA, Radecki SV, Hawley JR American Journal of Veterinary Research 66(3) pp506-511 concluded that “hypersensitization with CRFK cell proteins did not result in renal disease in cats during the 56-week study.”

A slightly later study, Interstitial nephritis in cats inoculated with Crandell Rees feline kidney cell lysates (2006) Lappin MR, Basaraba RJ, Jensen WA Journal of Feline Medicine and Surgery 8(5) pp353-6, found that 50% of the cats in the study who were given normal vaccines developed interstitial nephritis according to biopsies. However, these cats were vaccinated 12 times in 50 weeks, which is obviously far more often than is normal (the current US guidelines are for cats to be vaccinated only once every three years). One group of cats in the study were given intranasal vaccines, and they did not develop any signs of interstitial nephritis.

Risk factors for development of chronic kidney disease in cats (2016) Finch NC, Syme HM & Elliott J Journal of Veterinary Internal Medicine 30(2) pp602-10 states “A large proportion of the feline population receives regular vaccinations and, based on findings from previous studies described above, this practice may be considered a potential risk factor for CKD in cats.” It concludes “Our study suggests independent associations between both vaccination frequency and severity of dental disease and development of CKD” and states that further studies are necessary to investigate why this might be the case.

In 2012 Dr Lappin stated that in his research cats who developed antibodies did not go on to develop CKD. He recommends that core vaccines should continue to be given to healthy cats in accordance with the American Association of Feline Practitioners vaccination guidelines, which are available as 2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265.

Vaccinations: Feline Injection Site Sarcoma (FISS)

Many people are concerned about the risk of a cancer called feline injection site sarcoma (FISS), which is primarily associated with the rabies vaccine (and with the feline leukaemia vaccine), though it may also be seen following FVRCP vaccinations or other injections.

FISS is extremely rare — Vaccines and sarcomas: a concern for cat owners American Medical Veterinary Association explains more about FISS and states that the rate is about one cat in every 10000-30000 (a rate of 0.01-0.003%) — but that is not much consolation if it is your cat who is affected.

2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265 recommend that “veterinarians and owners monitor the vaccination site for swelling or lumps using the “3-2-1″ rule.” This basically means that the lump should be biopsied if: it is present three months after vaccination; is larger than two cm in diameter; or is increasing in size one month after vaccination.

FISS is difficult to treat because the tumour has to be medically excised, and it is necessary to go in very deep. For this reason some vets give vaccinations in a limb rather than the main body, for the rather morbid reason that the cancer can be more easily treated via amputation of the affected leg.

Some vets give vaccinations in the tail, on the basis that it is easier for a cat to manage without a tail than a limb. Tail vaccinations in cats: a pilot study (2014) Hendricks CG, Levy JK, Tucker SJ, Olmstead SM, Crawford PC, Dubovi EJ & Hanlon CA Journal of Feline Medicine and Surgery 16(4) pp275-280 found that vaccination in the tail was effective and states that should it be necessary, “tail amputation is minor surgery that can be performed by a general practitioner on an outpatient basis.” Tail vaccination in cats: balancing disease protection and cancer treatment (2013) University of Florida College of Veterinary Medicine discusses the study.

If you decide to have your cat vaccinated in the tail, ensure it is done correctly. 2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265 state that “vaccinations must be administered in the distal tail, something that may not be practical for most clinicians.”

Veterinary Partner discusses FISS and how to treat it.

Feline injection-site sarcoma: then and now (2013) Ford RB Today’s Veterinary Practice Jul/Aug 2013 pp54-57 explains more about how and why FISS began and how to treat it.

Feline injection site sarcoma guidelines 2015, updated 2021 (2021) Hartmann K & Hirschberger J European Advisory Board on Cat Diseases discuss prevention and management of FISS and state that additional treatments are usually needed in addition to removal of the tumour, such as radiation therapy.

Treatment of feline injection-site sarcoma with surgery and iridium-192 brachytherapy: retrospective evaluation of 22 cats (2020) Bloch J, Rogers K, Walker M, Dawson J & Wilson-Robles H Journal of Feline Medicine and Surgery 22(4) pp313-321 looked at implanting radioactive iridium to deliver radiation therapy to any tumour remaining after surgery. The study found that while there were some complications (the surgical wound opened in 77% of the cats), overall the treatment appeared to be as effective as traditional radiotherapy performed after surgery.

Feline injection site sarcomas: risk factors, diagnosis, staging, and treatment algorithm (2021) Intile J & Gareau A Today’s Veterinary Practice Jul/Aug 21 examines

Tufts University Cummings School of Veterinary Medicine (2018) reports on research into the use of a cancer medication called carboplatin to treat FISS.

Vaccinations: Whether to Vaccinate

Many people are reluctant to vaccinate their CKD cats, and some people are reluctant to vaccinate any of their cats, healthy or otherwise. This is usually because of concerns about frequency of vaccination (there is some debate about whether cats really need to be vaccinated annually) and fear of the cat developing FISS.

Vaccination decisions need to be tailored to the individual cat. 2013 AAFP Feline Vaccination Advisory Panel report 2013 Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 pp785-808 says “Vaccination is a medical procedure, and the decision to vaccinate, even with core vaccines, should be based on a risk/benefit assessment for each cat and for each vaccine antigen. Vaccination may indeed be beneficial, but it is not innocuous, and the benefit of vaccinating an animal (eg, the induction of clinically meaningful immunity) must be balanced against the risk of adverse events, likelihood of exposure and severity of disease. Where practical, every effort should be made to ensure that cats are healthy prior to vaccination; however, concurrent illness should not necessarily preclude vaccination.”

Vaccinations: Healthy Cats

Most healthy cats can receive vaccinations, though they may not be appropriate for cats receiving corticosteroids. Feline panleukopenia guidelines (2015) Hartmann K European Advisory Board on Cat Diseases says “In cats receiving corticosteroids, vaccination should be considered carefully. Depending on dosage and duration of treatment, corticosteroids may cause functional suppression of particularly cell-mediated immune responses, but pertinent studies are lacking.”

Antibody response to feline panleukopenia virus vaccination in healthy cats (2017) Bergmann M, Schwertler S, Reese S, Speck S, Truyen U & Hartmann K Journal of Feline Medicine and Surgery 20(12) pp1087-1093 gave FVRCP vaccinations to 112 cats who had previously been vaccinated less than twelve months earlier. Titres (see below) were checked before modified live FVRCP vaccination and then again after seven days and after 28 days. It found that only 48.3% of the cats in the study had an adequate response to the panleukopaenia part of the vaccination (defined as a fourfold titre increase). The study mentions that humans with CKD may be less likely to develop antibodies following vaccination, but it is not known if the same is true of cats. The cats in the study were more likely to respond if they had a low titre beforehand or had not been vaccinated previously. DSH cats responded better than purebreds. The study concludes “As none of the cats with high pre-vaccination antibody titres (≥ 1:160) had an at least four-fold increase in FPV antibody titres, measurement of antibodies rather than regular revaccinations should be performed. Thus, evaluation of FPV antibody titre in cats with previous vaccinations against FPV are recommended prior to revaccination.”

This study did only use one kind of vaccine (modified live) and collected data in a limited area. Nevertheless, it may support the idea that vaccinations, at least of the type used in the study, should not be given too frequently.

Vaccinations: CKD Cats

The caution details on a feline vaccine packet state that the vaccine is for administration to healthy cats only. CKD cats are by definition not healthy, so it used to be advised that they should not receive vaccinations. Once Thomas had been diagnosed, my vet said she did not recommend giving him vaccinations, so we stopped.

Recent guidelines take a different approach, recommending that cats with chronic but stable conditions (such as CKD) should in fact be vaccinated. 2013 AAFP Feline Vaccination Advisory Panel report (2013) Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 pp785-808 say “Whether older cats respond to vaccination in the same manner as younger animals do is inadequately studied. In the absence of data, the Advisory Panel recommends that healthy older cats and those with chronic but stable disease conditions receive vaccines in the same manner as younger adults. Less frequent vaccination is not advised due to inherent immunosenescence.”

Feline panleukopenia guidelines (2015) Hartmann K European Advisory Board on Cat Diseases says “In cats with chronic illnessvaccination may sometimes be necessary.Manufacturers evaluate vaccine safety and efficacy in healthy animals and accordingly label their vaccines for use in healthy animals only. Nonetheless, cats with stable chronic conditions such as chronic renal disease, diabetes mellitus or hyperthyroidism should receive vaccines at the same frequency as healthy cats. In contrast, cats with acute illness, debilitation, or high fever should not be vaccinated, unless there are compelling reasons to do so. In these cases, inactivated preparations should be used.”

One thing to bear in mind when considering whether to vaccinate a CKD cat is the fact that the cat is visiting the vet more often and thus being exposed to other patients with these viruses. 2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265 say “indoor only cats may also be exposed to infectious agents when brought to a veterinary clinic for a wellness examination. In theory, strictly indoor cats may be more susceptible to developing some infectious diseases (such as FPV and FCV infection) than cats with outdoor access because they may not receive “natural boosting of immunity” that occurs with natural exposure.”

This is a particular concern for CKD cats because they are immune-compromised, and non-vaccinated cats are therefore more vulnerable to catching the viruses against which core vaccines offer protection, especially if they are older (as most CKD cats are). The immune response to vaccination: a brief review (2013) Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 Supp pp1-3 say “While only limited feline-specific data exist, we know collectively from other species that, with age, the immune system undergoes profound changes resulting in an overall decline in immune function known as immunosenescence…Age-related declines in immune function directly translate into increased susceptibility of aged patients to infection, autoimmune disease and cancer.”

Titre Testing

Some people decide whether to give their cats vaccinations, particularly rabies vaccinations, by having titre testing done. This measures current levels of immunity so a decision can be made whether or not to revaccinate.

Centers for Disease Control and Prevention says “A rabies antibody titer is essentially an estimation of an immune response against rabies virus (either through exposure or vaccination). The RFFIT is one method which provides a laboratory measurement of the ability of an individual human or animal serum sample to neutralize rabies virus.” Kansas State University Veterinary Diagnostic Laboratory has more information about the RFFIT test. The test costs US$73 if you submit it directly to KSU.

There is no accepted titre level for proven efficacy. It should be remembered that titres only show a level of antibodies, but a positive level does not mean guaranteed protection against the virus in question. However, it may be reassuring if you opt not to give your cat vaccinations to have some indication as to whether your cat appears to have some residual immunity conferred by earlier vaccinations.

Titre testing will not exempt your cat from any legal requirements. One of my cats who had previously been through six months of UK quarantine had a rabies titre level that was ten times higher than that needed for a UK pet passport, but it was irrelevant: her rabies vaccinations had lapsed so we had to act as if she had never received any rabies vaccinations before and start from scratch.

Antibody titers versus vaccination (2013) Ford RB Today’s Veterinary Practice May/Jun 2013 pp35-39 has an excellent overview of the role of titres.

Vaccinations: Minimising the Risks

I understand that many people are very concerned about whether or not to vaccinate their CKD cats. There are ways to minimise the risks, as follows:

Vaccinations: Minimising the Risk: FVRCP

Here are some suggestions for minimising the possible risks of the FVRCP vaccine.

Vaccinations Frequency: FVRCP

In the USA, it is relatively common for vets to give core vaccines only once every three years. In the UK, many vets still continue to offer annual vaccinations. This may be because historically, the USA used killed vaccines whereas the UK used modified live vaccines, so the risk of FISS was thought to be much lower in the UK.

Vaccination of cats against infectious upper respiratory disease (2013) Ford RB Today’s Veterinary Practice Nov/Dec 2013 says that for adult cats “All cats should be revaccinated 1 year following completion of the initial series. Revaccination no more often than every 3 years is recommended for household pet cats living in low-density environments. Annual revaccination is indicated for cats housed in high-density environments, where risk for exposure to respiratory disease is high.”

However, 2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265 now advise that following the initial series of vaccinations given to kittens, the first top up should be given at six months of age, then three yearly thereafter. The six monthly shot may not be necessary if you are using an intranasal vaccine, but annual vaccination will be required.

Despite these guidelines, you will probably still be offered annual vaccinations if you are outside the USA and Canada. This is because that is what the manufacturers recommend. Disease information fact sheet feline herpesvirus 1 2013 Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 Supp pp1-3 states “”manufacturers recommend revaccination after 1 year. Published serologic and challenge studies indicate, however, that vaccination provides moderate protection in the majority of animals for up to 3 years or longer post-vaccination. Nevertheless, protection is not always complete shortly after vaccination and declines as the vaccination interval increases.”

Choosing not to vaccinate or to only vaccinate every three years in the UK can be problematic if your cat ever goes to a cattery, because catteries usually insist upon annual vaccinations. I asked my vet to write a letter to say vaccinations were not appropriate for Harpsie, and the cattery accepted this and allowed Harpsie to stay without recent vaccinations. However, 2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265 say “Cats entering boarding, breeding, foster, or shelter situations have increased risk of disease exposure as well as systemic stress. Vaccination may be warranted prior to entering these environments when possible.”

The immune response to vaccination: a brief review (2013) Scherk MA, Ford RB, Gaskell RM, Hartmann K, Hurley KF, Lappin MR, Levy JK, Little SE, Nordone SK & Sparkes AH Journal of Feline Medicine and Surgery 15 Supp pp1-3 say “Memory responses to vaccine antigens in aged patients, while less robust than in young adults, appear to be sufficient enough to maintain protective levels of antigen-specific antibody in the majority of cases. If a cat is routinely immunized through its adult years then maintaining vaccination protocols at recommended intervals is warranted in senior cats. Intervals do not need to be decreased because titers are likely to be maintained between boosts; however, intervals should not be increased either due to immunoscenescence.”

Vaccine Formulation Choice: FVRCP

Feline panleukopenia guidelines (2015) Hartmann K European Advisory Board on Cat Diseases says “In immunocompromised individuals, inactivated FPV vaccines are recommended. Modified live FPV vaccines should be used with caution in severely immunocompromised individuals, as the failure to control viral replication could potentially lead to clinical signs.”

Vaccinations: Minimising the Risk: Rabies

Use a vaccine at room temperature. Refrigerated vaccines have been associated with a higher rate of FISS according to Feline injection site sarcoma guidelines 2015, updated 2019 92019) Hartmann K & Hirschberger J European Advisory Board on Cat Diseases.

Some vets give vaccinations in the tail, on the basis that it is easier for a cat to manage without a tail than a limb, should amputation be necessary because of FISS. Tail vaccinations in cats: a pilot study (2014) Hendricks CG, Levy JK, Tucker SJ, Olmstead SM, Crawford PC, Dubovi EJ & Hanlon CA Journal of Feline Medicine and Surgery 16(4) pp275-280 found that vaccination in the tail was effective and states that, should it be necessary, “tail amputation is minor surgery that can be performed by a general practitioner on an outpatient basis.” Tail vaccination in cats: balancing disease protection and cancer treatment (2013) University of Florida College of Veterinary Medicine discusses the study.

Vaccinations Frequency: Rabies

Many vets offer annual rabies vaccinations, often because local laws require these vaccines to be given this frequently. From a medical perspective, however, less frequent vaccination is recommended. 2020 AAHA/AAFP feline vaccination guidelines (2020) Stone AES, Brummet GO, Carozza EM, Kass PH, Petersen EP, Sykes J & Westman ME Journal of the American Animal Hospital Association 56(5) pp249-265 say of rabies vaccinations “When local laws/regulations permit, the Task Force recommends a 3-year vaccination interval using a 3-year labeled vaccine.”

The Rabies Challenge Fund supported studies at the University of Wisconsin School of Veterinary Medicine which were aimed at demonstrating that the requirement for rabies vaccinations every three years in many USA states is unnecessary, and that rabies vaccinations may confer sufficient immunity for five or even seven years in dogs. It is quite probable that they also last a long time in cats.

Discuss the best approach for your cat with your vet.

If you opt for three yearly vaccinations, you should still take your cat to the vet for regular (yearly minimum for healthy cats) check ups.

Vaccine Formulation Choice Rabies: PureVAX

Most rabies vaccines contain adjuvants, which have been associated with an increased risk of a form of cancer known as FISS.

The PureVAX feline rabies recombinant rabies vaccination is considered safer by many because it is non-adjuvanted. Make sure your vet knows you want your cat to be given the non-adjuvanted recombinant version rather than the killed vaccine.

This vaccine is available both as a one year and as a three year vaccine (rumour has it they are in fact one and the same and are simply labelled with different validities). Three year duration of immunity in cats vaccinated with a canarypox-vectored recombinant rabies virus vaccine (2012) Jas D, Coupier C, Toulemonde CE, Guigal PM & Poulet H Vaccine 309490 pp6991-6996 tested the effectiveness of the PureVAX rabies vaccine in cats and states “This vaccination regimen induced a strong and sustained antibody response, and all vaccinated animals were protected against virulent rabies challenge carried out 3 years after vaccination.”

This vaccine is normally acceptable for cats holding UK pet passports (though always check in case regulations have changed). My cats received the one year PureVAX rabies shots (the three year option was not available at the time) during the period when it was necessary for them to receive them and had no problems with them, despite being over the age of ten at the time.

The European Medicines Agency has more information about the PureVAX three year rabies vaccine.

Rabies Exemption USA

A few US states only require the rabies vaccine to be given every three years, but in others you may be required by law to have your cat vaccinated against rabies annually.

However, your state may permit your cat to be given a medical exemption from the rabies vaccination requirement. The following states permit exemptions in principle, though only on a case by case basis: Alabama, California, Colorado, Connecticut, Florida, Illinois, Maine, Massachusetts, Maryland, New Hampshire, New Jersey, Nevada, New York, Oregon, Pennsylvania, Vermont, Virginia and Wisconsin. The American Veterinary Medical Association has information about the particular requirements of each state but states “Advanced age of the animal or a desire on the part of the client or veterinarian to minimize the use of vaccinations (in the absence of a specific contraindication to vaccination) should not be considered sufficient justification for issuing a rabies vaccination waiver.”

A medical exemption (waiver) is merely evidence that you are in compliance with the law. The American Veterinary Medical Association says “a waiver only serves to allow the animal to be properly licensed in compliance with animal control regulations where this is allowed…If the animal with a rabies vaccination waiver is involved in a potential rabies exposure incident, the animal shall be considered unvaccinated against rabies for the purpose of enforcing appropriate public health regulations.”

If your cat bites somebody (e.g. your vet) in the USA, you will normally be asked to provide evidence of rabies vaccination. Some people who do not vaccinate their cats against rabies instead obtain titre measurements (see above), but in the USA no state currently accepts a rabies titre as the legal equivalent of rabies vaccination, so your cat would probably be subject to quarantine. This may be as short as ten days, and in some cases the quarantine may take place in your own home, but this is not always the case.

This is despite the findings of Compendium of animal rabies prevention and control (2016) National Association of State Public Health Veterinarians; Compendium of Animal Rabies Prevention and Control Committee; Brown CM, Slavinski S, Ettestad P, Sidwa TJ, Sorhage FE Journal of the American Veterinary Medical Association 248(5) pp505-517, which advises that cats overdue for a rabies vaccination who are exposed to rabies should have a rabies booster shot followed by an observation period rather than be subject to quarantine or euthanasia.

Dogs and cats overdue for vaccination — recommendations for updating immunizations (2012) Ford RB Today’s Veterinary Practice Nov/Dec 2012 pp26-32 explains what to do to bring your cat’s immunisations up to date.

Vaccinations: What to Do if Your Cat Has a Reaction

Firstly, don’t panic. Minor reactions are not unknown. One of my cats was always under the weather for a few days after vaccinations, a bit lethargic and subdued. As long as your cat eats (assist feed if necessary) and drinks, you will probably find s/he is fine after a few days.

If you find a lump, also don’t panic. The chances of it being FISS are vanishingly small. You normally only need to be concerned if:

The lump has been present for more than three months after vaccination
The lump is growing
The lump is bigger than 1 inch (2cm) in diameter.

Even then, it might not be FISS, but of course you should consult your vet.

If your cat does develop FISS, some vaccine manufacturers may assist with your veterinary costs if you have complete vaccination records to support your claim. One member of Tanya’s CKD Support Group successfully did this.

This page last updated: 07 June 2022

Links on this page last checked: 05 June 2022