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Cat fever: what EVERY cat keeper should know about it?

Cat fever

Pets, who live in close company of their owners, are usually closely watched by them, which of course allows you to quickly spot any deviations from the accepted norm.

In other words, an attentive owner of a dog or cat will very quickly notice that his pet behaves differently than usual, which often rightly arouses anxiety and will result in going to the nearest veterinary clinic.

Animals, like small children, will not tell us that they feel bad and that something is wrong with them, but only by their behavior they manifest a worse disposition.

From the very beginning, I will risk saying that most diseases in our companion animals, especially those that are infectious and infectious, begin with very harmless-looking symptoms.

It is these small, very subtle changes in behavior, greater drowsiness, avoidance of movement, less physical activity or refraining from food or water, that may indicate the onset of many systemic diseases.

These often non-specific symptoms, although they do not immediately answer the question of what is wrong with the patient, provide very important information:

that there is a problem with which we should go for veterinary help.

They are a very clear signal that something bad is happening in the body that should absolutely not be underestimated and which requires further, in-depth diagnostics.

A perfect example of everything I am writing about is the well-known symptom of fever, i.e. elevated body temperature, commonly associated with bacterial or viral infections.

In this article, I will try to explain to you what it is in a clear and clear way fever, what diseases accompany it, what are its symptoms in felids, how to treat it.

In short, I will try to present everything that a conscious cat owner should know about this important, non-specific disease symptom.

  • Cat body temperature and methods of its measurement
  • What is a fever in a cat?
  • The biological significance of fever in a cat
    • Change in behavior during fever
  • With what diseases does fever occur?
  • Fever of unknown origin
  • Fever symptoms in a cat
  • How to fight a fever in a cat?
    • Non-steroidal anti-inflammatory drugs
    • Tolfenamic acid
    • Meloxicam
    • Steroid drugs
    • Antibiotics
    • Physical methods to help fight fever

Cat body temperature and methods of its measurement

How to take a cat's temperature?

At the outset, we must be clear that the temperature will vary in different places of the cat's body and is not a constant value.

Probably no one will be surprised that the skin, i.e. the outer shell of the body, will be cooler than the deeper internal organs, for example in the abdominal cavity.

In addition, the skin will sometimes show significant temperature fluctuations depending on environmental conditions, while, for example, the liver or kidneys will be characterized by a constant temperature independent of the environment, i.e. they will be thermally stable.

Therefore, it has been conventionally assumed that the body temperature is that measured in the rectum, vagina or oral cavity, and in the armpit of a human being.

Otherwise we could say that it is internal body temperature which is, of course, some medical simplification.

In more detail, we can talk about the temperature of the rectal, vaginal or oral cavity, which probably most closely corresponds to the homothermic, i.e. constant temperature of the inside of a mammal.

Of course, for all practical reasons, we rather avoid measuring the temperature in the mouth of a cat, which will involve the risk of damaging the thermometer itself due to biting it.

Most often, in veterinary practice, we choose to measure the rectal temperature, i.e. we determine the rectal temperature.

A more complicated method that provides more data is thermography based on infrared radiation emitted by the body, presenting the result as an image of the animal's body temperature, otherwise a specific temperature map.

And although this method is certainly extremely modern and diagnostically valuable, it has not found widespread recognition in routine veterinary practice, but rather in scientific research, probably due to the need for complicated measuring equipment.

The normal core temperature of a healthy cat, measured in the rectum, is considered normal 38.0-39.5 degrees Celsius (38-39 according to other sources).

So how exactly do we see much more than in the case of a human.

In humans, such temperature values ​​indicate a fever, while in a cat they are an expression of a normal internal temperature.

Therefore, the temperature in a cat is considered to be a fever more than 39.5, and the lowered temperature is the value below 37.5 (38).

Young kittens may have a slightly higher normal temperature, hence 39.5 is not a cause for concern, of course in the absence of other clinical signs.

Importantly, from a practical point of view, the correct internal temperature is subject to certain changes depending on the time of day and night.

Well, in cats, its highest values ​​will be noted in the evening and at night and lower during the day so at a time of lower activity.

The differences in daily temperature fluctuations can be as high as from 0.5 to 1 degree so they can be significant.

Other physiological factors can also influence the measured internal temperature.

Normal food intake and digestion causes the temperature to rise in the range even up to 1 degree, similar to oestrus in cats when they are strongly influenced by estrogens.

Remember that both too high internal temperature and too low temperature are extremely dangerous for the proper functioning of the body.

And so the state hyperthermia that is, an increase in temperature above the correct value becomes a direct threat to life because it causes protein denaturation (limit value above 43.5).

Hypothermia, i.e. a drop below the normal value, is well associated with cooling down and freezing of the body and, as we all know, it is extremely dangerous for life.

From the basic physiological information, we must remember that the center controlling the maintenance of the correct temperature in the body is located in hypothalamus.

What is a fever in a cat?

Fever in a cat is the first disease symptom known by man and is commonly associated with infection and infectious agents, which since time immemorial has been equated with an ongoing epidemic, plague. Fever is the increase in the body's internal temperature to a higher level resulting from the shifting of the heat of the neurons of the thermoregulation center in the hypothalamus to higher values ​​by substances present in the body with pyrogenic, i.e. feverish properties.

What is a fever in a cat?

In other words, these factors trigger a higher temperature in the body, raising the bar within the thermoregulation center.

It is because of the presence in the blood or intercellular fluid exogenous pyrogens in turn, there is a release endogenous pyrogens and the occurrence of the phenomenon of increased temperature of the system.

For example, they are exogenous pyrogens endotoxins released by gram-negative bacteria, bacterial toxins if viral proteins triggering very complicated changes at the level of not only the thermoregulation system but also the immune system.

We must always distinguish fever from the state of hyperthermia, because the mechanisms of its formation are definitely different.

It looks a bit more detailed as follows.

With fever in a cat, the temperature of the hypothalamic pattern is raised by pyrogens, while hyperthermia does not alter the pattern.

The physiological mechanisms in fever lead to a decrease in heat transfer to the environment, an increase Tremor thermogenesis with a consequent increase in the internal temperature.

In a state of hyperthermia, the body tries to dissipate heat to the environment ineffectively and thus lower the temperature which is above the standard of the thermoregulation center.

In other words, in a cat's fever, we have the efficiency and capacity of thermogenesis processes and heat dissipation to the environment, and the cat's body does not defend itself against higher temperatures.

Subjectively, he may even feel cold, especially in the phase of rising fever.

In hyperthermia, rightly associated with overheating, the cat will defend itself against the increase in temperature and will subjectively feel heat, and the mechanisms responsible for heat dissipation will be ineffective, which will translate into a life-threatening temperature.

Although the fever will increase the temperature, it will not exceed it to a lethal value, which may occur in the event of hyperthermia.

And what is extremely important, the administration of antipyretic drugs that affect the synthesis of inflammatory factors will reduce the temperature in the event of fever and will not change it in the state of hyperthermia.

The lethal or lethal temperature is not exceeded in the fever by action cryogens that is, endogenous substances of a hormonal nature (e.g. interleukin 10, vasopressin, tumor necrosis factor), which regulate the physiological temperature of the body by lowering the temperature of the thermoregulation center.

Although fever may seem strange to many, it is of a kind the body's defense mechanism.

By increasing the internal temperature, the system creates worse conditions for the development of pathogens entering it from the outside, which is a favorable phenomenon in the fight against infection.

Many bacteria or viruses multiply much less at a higher temperature, so a sick organism, by increasing the temperature, hinders their development and complicates life.

Interestingly, raising the body temperature does not always have to mean a medical condition, but it may result, for example, from a situation of severe stress.

More than once, in my own veterinary practice, I have encountered a situation where a stressed cat, taken out of the carrier, had above normal body temperature and at home, in a friendly environment, behaved completely normally.

The mechanisms responsible for the development of this type of stress fever require the activation of adrenergic receptors in the central nervous system.

The biological significance of fever in a cat

Probably more than one cat owner asks himself why a fever at all, if it is associated with bothersome symptoms.

It may seem strange and at least incomprehensible to say that fever has a beneficial effect while an infection is present.

Increasing the internal temperature not only inhibits the development and multiplication of pathogens, i.e. viruses, bacteria or protozoa, but also stimulates processes aimed at their destruction, and thus improves the fight against the disease.

The phenomenon is stimulated phagocytosis and a number of other immune reactions, which will be reflected in the faster getting rid of the disease.

In a feverish state, the secretion of a number of hormonal factors changes from adrenocorticotropic hormone, vasopressin, thyreoliberin, endorphin and melanotropin at the forefront.

All these modifications can be included in the so-called. acute phase reaction, which is the early stage of the body's defense against infection.

All this in order to efficiently, quickly and most importantly effectively get rid of pathogens, thus restoring the state of homeostasis of the body associated with health.

At the same time, as I have already mentioned, there are a number of regulatory mechanisms keeping the fever within certain limits that are safe for the system.

Change in behavior during fever

There are also many fever behavioral changes manifested in a change in the behavior of the animal.

And although it may seem very unfavorable to us and at the same time be the reason for visiting a veterinary clinic, from a biological point of view it serves to fight the disease.

A feverish cat will show worse well-being, become less active, mobile, lose its appetite and be more sleepy, which, however, has a deep sense to protect the body, its energy reserves or minimize the threats lurking in the surrounding environment.

Such a cat, hiding in hard-to-reach places, will not be an easy prey for other predators larger than it.

Of course, all these changes are beneficial as long as they do not last too long.

With time, the body's reserves will always be exhausted and the ability to fight the disease will be lost.

Long-term fever, often inherent in an incurable disease, will gradually lead to progressive wasting.

A fever is therefore a clear signal that something bad is going on in the body and we should quickly try to determine the cause of this state of affairs without waiting for the cat to deal with the disease on its own.

With what diseases does fever occur?

With what diseases does a cat have a fever?

Cat fever, as we already know perfectly well, it is a nonspecific, nonspecific and not characteristic symptom occurring in many health problems in felids.

Therefore, it is not possible to make a preliminary diagnosis only on the basis of its statement, without having any other more specific disease symptoms.

It is a kind of a signal that the cat's body is fighting a disease that must be examined in more detail.

The list of diseases associated with elevated internal temperature is enormous and impressive.

Starting with the frequent performers feline infectious diseases fever accompanies catarrh or kalita i herpesvirosis and bacterial complications (Pasteurella spp. Bordatella bronchiseptica, streptococci, staphylococci or mycoplasmas).

It also occurs with severe generalized calicivirosis associated with high mortality, which, fortunately, often does not occur in us.

In another viral disease, which is leukemia in cats, the temperature does not exceed 39.0, but due to the permanent, permanent state it leads to progressive dehydration of the body.

Similarly, in the case of viral immunodeficiency, i.e. FIV in cats equivalent to human AIDS fever is a common symptom of secondary bacterial infections and a significant decline in immunity.

It also occurs with:

  • infectious peritonitis,
  • cat pox,
  • feline haemotropic mycoplasma,
  • tuberculosis,
  • salmonellosis,
  • brucellosis,
  • Q fever,
  • bordatellosis,
  • yersiniosis.
In fact, a cat's fever can appear with any infectious bacterial or viral disease.

In the case of generalized diseases, we also encounter a feverish condition in a cat.

And so for example hepatitis various background, inflammation of the pancreas, peritoneum, stomach and intestines, kidneys, bladder or even skin, it can give the symptom of fever as one of many coexisting.

Any diseases related to the cat feeling severe pain and the related discomfort will be associated with an increase in the correct body temperature.

After injuries, accidents, contusions and fractures, there will always be stress inherent in fever.

Also, frequent abscesses after being bitten as a result of fights in cats will show a symptom of fever.

Likewise, most nonspecific inflammations of various organs (teeth, gums, ears, kidneys, peritoneum, eyes, pancreas, liver and lungs) are often accompanied by fever, which is one of the hallmarks of ongoing inflammation.

A fever will accompany the ongoing neoplastic process in the body (acute and chronic leukemia, lymphomas, myeloma), especially in the event of metastasis or when the cancerous tumor breaks down.

An important group of febrile diseases will be those of the immune background:

  • polyarthritis,
  • systemic lupus erythematosus,
  • hemolytic anemia.

As I wrote before, any stressful situation, which undoubtedly is even the smallest disease, may manifest itself in an increase in internal temperature.

Raising the body temperature is a characteristic feature of inflammation and an expression of the body's fight against pathology.

Interestingly, fever can also occur with certain medications (tetracyclines, sulfonamides if penicillins) in the process of tissue necrosis if overactive thyroid gland.

So we can clearly see how extremely difficult it is sometimes to diagnose the etiological, causative factor of the disease, especially in the absence of other specific, pathognomonic symptoms indicating a specific disease.

I am writing about it especially in the context of the fight against a long-lasting fever, which not only worsens the general well-being of our ward, but also causes a number of very unfavorable pathophysiological changes.

Fever of unknown origin

This type of fever is a bane not only for veterinarians but also for pet owners who go to the clinic for help and expect a reliable and accurate diagnosis and the treatment that follows.

However, this is not always possible

Sometimes we have a fever, i.e. a signal about an ongoing disease, but we are unable to make a diagnosis.

The term fever of unknown origin will therefore refer to the cases of cats in which the fever persists after the use of antibiotics and the additional tests performed (morphology, biochemistry or urinalysis) do not provide an answer as to the causes.

In English-speaking countries, doctors adhere to the principle that fever is usually caused by an infection and therefore almost always administer antibiotics with a broad spectrum of activity, which in a large proportion of cases improve.

A positive reaction to an antibiotic is treated as diagnosis through treatment, which also allows you to abandon laboratory tests.

In humans, fever of unknown origin accompanies infectious diseases, neoplastic processes and autoimmune diseases.

As is supposed to be the case with felids.

A comprehensive approach to this type of fever requires a thorough clinical interview supported by laboratory tests and completed with a treatment trial.

Fever symptoms in a cat

Fever symptoms in a cat

Once we know a bit about the fever itself, now let's consider what symptoms may indicate its occurrence, i.e. what to look for in the behavior of our cat.

Firstly fever in a cat as in humans, it will significantly worsen the animal's well-being.

Of course, a sick cat will not tell us this, but it will certainly manifest its strange behavior, which will differ from the current norm.

A suffering cat will become a much less active animal, avoiding playing, hunting or jumping, but relying more and sleeping.

He can choose unusual places and hide there, avoiding contact with people.

When forced to play, he may be very reluctant, apathetic and sometimes even aggressive towards our hands or other previously liked animals.

He refuses to accept or eat his favorite food, skipping a bowl full of a delicacy eagerly eaten so far.

He often refuses to take water, which additionally leads to progressive dehydration of the body and thus worsens the general well-being.

After all, the fever itself also leads to dehydration.

A feverish cat gives the impression of a sad, apathetic, weakened animal, avoiding everything that has been its favorite activity until now.

He may also meow excessively, which by a concerned owner is often interpreted as a way of seeking help and drawing attention to himself or, on the contrary, be excessively silent and behave as if he was not there.

He also does not always excrete feces and urine properly, often avoiding the litter box altogether or dealing with unusual places.

The fever accompanying any disease will produce symptoms characteristic of that disease.

For example, at pneumonia in your cat one of the predominant symptoms will be present exercise intolerance and dyspnoea manifested by difficulties in breathing and shortness of breath, and fever will be an accompanying symptom.

In fact, fever is one of the many parallel symptoms that coexist in a given infection and it is difficult to determine exactly what symptoms are only related to it, separating them from the current disease.

Remember that a hot nose or ears do not necessarily indicate a high internal temperature and to be at least an expression of the cat lying close to the radiator.

On this basis, we cannot conclude with any certainty that there is a fever.

After all, there are cats who love to lie close to a fireplace or other heat source, which will have a really hot fur when we touch them with a hand and at the same time will have a completely normal body temperature.

How to fight a fever in a cat?

How to fight a fever in a cat?

First of all, we should always try to find out what causes the increase in internal temperature and only then prescribe appropriate treatment aimed at the cause of the disease.

Correct diagnosis will allow the treatment to be directed in such a way that we will act on the cause of the problem and not on itself, as I would like to emphasize one of many, the symptom.

Personally, I always measure the temperature of the cat at the beginning of the visit to the office, which to some extent eliminates the increase in it caused by stress due to prolonged stay in a foreign place, which is a veterinary office.

Often, taking the cat out of the carrier, earlier testing or blood sampling, and then measuring the rectal temperature may not be fully reliable and unreliable.

Under no circumstances should we undertake the self-treatment of fever and the administration of temperature-lowering drugs used in humans.

Although a cat lives with humans, it is characterized by a different metabolism and transformation of drugs, different processes of oxidation or biotransformation of xenobiotics, and therefore even seemingly safe over-the-counter human drugs can be deadly to him.

So do not use aspirin, ibuprofen, naproxen or the iconic "Apap " on your own, because such action may bring more harm than benefit and additionally end up with quite serious poisoning.

When the correct diagnosis is made and the appropriate causal treatment is implemented, e.g. antibacterial agents, the elevated temperature should itself drop to normal over time.

When the temperature is high, however, I do not suggest waiting for it to drop as a result of chemotherapeutic agents, but also introduce appropriate antipyretic drugs.

Of course, we have a whole range of safe and effective antipyretic drugs on the veterinary market that are worth using to lowering the temperature of the cat.

They are produced both in tablets and injections, so we have a lot to choose from.

Non-steroidal anti-inflammatory drugs

Most of them belong to non-steroidal anti-inflammatory drugs that is, as the name suggests, influencing the inflammation in the body.

They show an action:

  • anti-inflammatory,
  • painkillers,
  • antipyretic.

Their mechanism of action is inhibition of cyclooxygenase I and II that is, the enzymes involved in the formation arachidonic acid, whose end products are prostacyclin, thromboxanes and prostaglandins that is, important mediators of the inflammatory process.

Cyclooxygenase comes in two versions, the first form of which is needed in the body and blocking it causes a number of side effects.

The older the drugs are, the more potential damage they can cause to the body.

Hence the necessity of skilful use of these products and knowledge of possible side effects.

The point is, in a nutshell, that by fighting a fever it is not possible to cause even life-threatening conditions gastrointestinal bleeding and his ulcers, which may end perforation and peritonitis.

The analgesic and antipyretic effect is mainly due to the inhibition of cyclooxygenase II activity.

So we choose only those medications registered for cats and use them only for the period that is absolutely necessary, usually several days.

We should not use drugs with strong antipyretic properties dedicated to dogs, a perfect example of which is that sodium metamizole (preparation Biovetalgin or human Pyralgina), which is not registered as a product for cats.

Tolfenamic acid

One of the recommended products for fighting fever in cats is tolfenamic acid present in the preparation Tolfedine (tablets and injection).

This drug with a strong antipyretic effect is especially recommended in diseases of the upper respiratory tract in cats in conjunction, of course, with antibiotic.

Importantly, as most drugs in this group, they should not be used in the case of suspected gastrointestinal ulceration, blood coagulation disorders, and in animals with kidney diseases, heart and liver diseases.

It cannot be combined with steroid drugs and special care should be taken when dehydration because it may be associated with nephrotoxic effects, i.e. kidney damage.

When deciding to choose tolfenamic acid, we should administer antibiotics at the same time, because the acid itself can impair phagocytosis and fight bacteria by the body.

And yet it is infection that is often the cause of elevated internal temperature, so we should not interfere with the natural processes of fighting pathogens.


Another frequently used active ingredient to combat inflammation, pain and fever is meloxicam present in preparations:

  • Animeloxan,
  • Loxicom,
  • Meloxal,
  • Metacam.

Steroid drugs

Instead of the commonly used NSAIDs, some clinicians use steroid drugs showing a strong anti-inflammatory effect.

Admittedly steroids they have a number of side effects, but in felids they are considered safe, especially for short-term use.

They inhibit the inflammatory reaction and thus reduce the fever.

They are especially recommended for diseases of the immune background.

From a practical point of view, we should not combine them with non-steroidal drugs, which reduces the risk of side effects.

So let's not be afraid of steroids, especially in the case of their short-term use.


In case of infections, an empirically selected antibiotic with antibacterial activity turns out to be extremely helpful.

Personally, I would use a broad-spectrum antibiotic that is also safe for a cat, e.g. amoxicillin with clavulanic acid.

Physical methods to help fight fever

A number of physical methods to lower the temperature can also be used.

Although they are used less and less often, they are sometimes very effective.

By this I mean cooling the cat with cold compresses or giving cold fluids or placing it in a cooler environment (but not in the refrigerator)!).

In the past, it was also used to immerse a feverish cat in cool water, which can certainly be considered effective, but at the same time not well tolerated by most cats, and additionally too stressful.

Because most cats do not tolerate baths very well, so nowadays they are rarely done to keep the temperature down.

In fact, each of the physical methods is good as long as it is effective and safe for the cat (it should not cause unnecessary stress in an already ill cat).


Is the fever dangerous for the cat??

Cat fever is a frequent and extremely nonspecific symptom of disease, each time requiring the implementation of effective antipyretic treatment and, above all, correct diagnosis.

I write about it often to make you aware of the importance of not delaying a visit to the doctor and:

  1. First, finding a fever.
  2. Then fighting it.

Because although it is beneficial from a biological point of view, it also worsens the well-being of the domestic cat.

By informing about the ongoing inflammation and infection, it allows you to quickly introduce causal treatment, which in most cases turns out to be effective, bringing quick improvement.

Therefore, I do not wish anyone a fever, I would like to clearly visualize everyone not to be afraid of it and to treat it a bit as a "friend " who will allow you to recover faster, which I wish to all cat owners and their pets.

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