An increase in body temperature above the normal range is referred to as fever. In dogs and cats, this is a body temperature above 40 degrees Celsius (see also normal values for dogs and cats).
Fever and overheating (—> Overheating) are not the same thing.
Fever
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Guide to fever in dogs and cats
Fever
Fever is a regulated increase in body temperature by the body in response to inflammation, infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., or immune processes. In dogs, fever is usually spoken of from about 39.2–39.5 °C. High or persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. fever can strain the circulation and organs and should be clarified.
Fever is a natural defense reaction of the body, in which the body temperature rises above the normal range. In dogs and cats, we speak of fever when the body temperature is above 39.5°C. We speak of high fever in our pets from a temperature of 40°C, while critical fever is present from 41°C. The normal temperature in dogs is 37.5–39.0°C, in cats 38.0–39.0°C. However, these values can vary slightly individually and are influenced by factors such as time of day, physical activity, and ambient temperature.
The sudden onset of high fever differs fundamentally from a slow increase in temperature. While a gradual increase gives the body time to adapt, a rapid increase in temperature puts a particular strain on the organism. The rapid change can lead to greater impairments and is often an indicator of acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention., potentially life-threatening diseases.
It is important to distinguish between fever and hyperthermiaHyperthermia refers to an elevated body temperature beyond the normal range. In dogs and cats, this can be caused by overheating, Fever, or certain diseases, and often requires urgent medical attention.. Fever is caused by a change in the body’s own temperature regulation center in the hypothalamusThe hypothalamus is an area of the brain that plays a central role in regulating Hunger, thirst, sleep, body temperature, and other autonomic functions. It controls the pituitary gland through the production of hormones., usually as a reaction to pathogens or inflammatory processes. HyperthermiaHyperthermia refers to an elevated body temperature beyond the normal range. In dogs and cats, this can be caused by overheating, Fever, or certain diseases, and often requires urgent medical attention., on the other hand, is overheating due to external factors such as high ambient temperatures or excessive exertion, whereby the temperature regulation center functions normally, but heat dissipation is impaired.
Causes
Fever is usually a sign of an infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. The body’s reaction to raise the body temperature is helpful and should not be combated as a matter of principle. More attention should be paid to the cause of the fever.
- BacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease., Parasites, VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants.
- Tumors
- Autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus.
- ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. inflammatory diseases
- Hormonal disorders
- Blockage of a blood vessel (thrombosisThrombosis is the formation of a blood clot in a blood vessel that can obstruct or block blood flow. Thromboses can occur in veins (venous thrombosis) or arteries (arterial thrombosis).)
Attention, in cats, a blockage of a blood vessel in the pelvic area is not uncommon. In these cases, the rectalRectal refers to anything involving the rectum, including administering medication or performing examinations via the anus. temperature is not increased, but decreased due to the reduced blood flow.
Sudden high fever in dogs and cats can be triggered by various factors, with infectiousInfectious describes the ability of a pathogen to be transmitted from one individual to another and trigger an infection. It also refers to diseases caused by such pathogens. causes being the most common. The most important triggers include:
AcuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. bacterial infections are a common cause of sudden high fever. SepticemiaSepticemia, often used synonymously with sepsis, is the presence of bacterial pathogens in the blood that trigger a systemic inflammatory response. It is a medical emergency that requires immediate treatment. is particularly dangerous, in which bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. enter the bloodstream and spread throughout the body. This can arise from local infections such as wound infections, abscesses, gingivitis, or urinary tract infections. Leptospirosis, a bacterial zoonosisA zoonosis is a disease or infection that can be naturally transmitted from animals to humans. Examples include rabies, Lyme disease, and avian influenza., can cause sudden high fever in dogs and is transmitted through contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. water.
ViralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. infections such as parvovirus or distemper in dogs, as well as felineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. panleukopenia or felineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. cold, can also lead to a rapid increase in fever. In cats, FIP (FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. InfectiousInfectious describes the ability of a pathogen to be transmitted from one individual to another and trigger an infection. It also refers to diseases caused by such pathogens. Peritonitis) and FIV (FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Immunodeficiency VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants.) can be associated with fever. ParasiticParasitic refers to diseases or conditions caused by parasites. Parasitic infections can affect the digestive tract, skin, and other organ systems. diseases such as babesiosis, ehrlichiosis, or anaplasmosis, which are transmitted by ticks, are other possible causes.
Non-infectious causes include immune-mediated diseases such as hemolytic anemias or polyarthritides, which arise from misguided immune responses. Neoplasias (tumorA tumor is an abnormal growth of tissue that can be benign or malignant. Tumors can develop in any part of the body and affect various functions. diseases) can also be associated with fever, especially lymphomas and leukemias. Poisoning from toxins such as certain plants, medications, or chemicals can lead to a febrile reaction.
The so-called “Fever of Unknown Origin” (FUO) deserves special attention, in which no clear cause for the fever can be found despite extensive diagnostics. These cases require particularly thorough investigation and monitoring.
In cats, it should be noted that a blockage of a blood vessel in the pelvic area (arterial thromboembolismThromboembolism is the blockage of a blood vessel by a blood clot (thrombus) that has formed in one place in the circulatory system and then moved to another location. This can lead to serious complications, such as a stroke or pulmonary embolism.) can paradoxically lead to a decreased rectalRectal refers to anything involving the rectum, including administering medication or performing examinations via the anus. temperature, while the rest of the body has a fever – an important diagnostic clue for veterinarians.
Symptoms
Sudden high fever in dogs and cats
Typical Symptoms:
- Lethargy, reduced food intake, feeling of warmth
- Shivering, Panting (not only in heat), increased heart rate
- In cats, often withdrawal, “painful” behavior
Alarm signs:
- Very high fever or fever plus apathyApathy refers to a state of indifference and reduced interest or lack of emotional involvement in activities or events that would normally arouse interest./weakness
- Neurological symptoms (ataxia, Seizures), stiff neck
- RespiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, pale mucous membranes, petechiaePetechiae are small, pinpoint skin hemorrhages caused by blood leaking from the capillaries. They can indicate a variety of conditions, including infections, allergic reactions, and blood clotting disorders.
- Puppies/kittens, geriatric animals, immunosuppressed patients
Escalation/course:
- Fever > 24–48 h without recognizable cause → clarification
- Increasing deterioration within 6–12 h → urgent
- Fever + dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse./Vomiting/Diarrhea → escalation due to circulatory risk
The clinical picture of an animal with sudden high fever includes characteristic symptoms that are due to the increased metabolism and the immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens.. Typical signs include: lethargy, Panting, thirst, Pain, loss of appetite, no water intake, RespiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, Swelling, and sometimes Vomiting.
General impairments are shown by pronounced lethargy and fatigue. The animals appear apathetic, withdraw, and avoid movement. Loss of appetite up to complete food refusal is often observed, while at the same time thirst is often increased. Many animals show an altered posture with a hunched back or drooping head.
The physical signs include hot and dry mucous membranes and an increased respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. rate. Dogs react with increased Panting, while cats often breathe with their mouths open, which is unusual behavior for them. The heart rate is significantly increased, and warm ears and paws are noticeable during the examination. A change between chills and a feeling of heat is also characteristic, whereby the animals can shiver despite a high body temperature.
In cats, the symptoms may be more subtle than in dogs. They hide more often and show less obvious signs of illness. An important warning sign in cats is the complete loss of grooming.
The severity of the symptoms does not always correlate with the height of the fever. Some animals already show clear impairments at 40 °C, while others hardly show any symptoms at the same temperature. At temperatures above 41 °C, clouding of consciousness, Convulsions, and collapse can occur, as extreme hyperthermiaHyperthermia refers to an elevated body temperature beyond the normal range. In dogs and cats, this can be caused by overheating, Fever, or certain diseases, and often requires urgent medical attention. can lead to organ damage.
In addition to these general fever symptoms, other specific signs may occur depending on the underlying disease, such as Cough in respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. infections, Vomiting and DiarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems. in gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. diseases, or Lameness in Joint inflammation.
First Aid
- Use a digital thermometer. Ear thermometers are often easier to use, but less accurate (Fig.).
- Put some Vaseline or oil on a commercially available fever thermometer and insert the thermometer rectally about 2 cm (cat, very small dog) to 5 cm (large dog) and wait until the temperature no longer increases. The rectum runs straight, so you don’t have to worry about damaging the intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients..
- Do not let go of the thermometer and remove it if the animal is very restless.
- An animal with fever needs rest.
- Make sure your animal drinks enough.
- You can recognize a lack of fluids, for example, by the fact that less urine is excreted and this looks more concentrated, darker than usual.
- Do not use antipyreticAntipyretic drugs are medications used to reduce Fever. They work by acting on the heat-regulating center in the brain, thus regulating body temperature. These medications can be used in dogs and cats to reduce Fever, which is often a symptom of an infection or inflammation. drugs without veterinary advice.
Diagnosis
The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of a sudden high fever begins with the correct temperature measurement. RectalRectal refers to anything involving the rectum, including administering medication or performing examinations via the anus. measurement with a digital thermometer is considered the gold standard. The lightly oiled thermometer is inserted about 2 cm (cat, small dog) to 5 cm (large dog) into the rectum. Alternative measurement methods such as ear thermometers offer more comfort, but provide less precise results.
After the fever has been determined, a systematic diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. follows to clarify the cause. The thorough medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. records previous illnesses, vaccinationVaccination is the process of administering a vaccine to develop immunity against a specific infectious disease. It is one of the most effective methods of prevention of infectious diseases. status, medication administration, travel historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits., and possible exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. risks. During the clinical examination, all organ systems are systematically examined, with particular attention being paid to signs of inflammation, Swelling, and Pain.
The laboratory diagnostic tests form a central component of the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients.. The blood count can provide important clues: Leukocytosis indicates bacterial infections, while leukopenia is more likely to occur in viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. infections or sepsisSepsis is a life-threatening condition caused by the body's overwhelming response to an infection, which can lead to damage to its own tissues and organ failure.. Blood chemistry provides information about organ functions and metabolicMetabolic refers to metabolism, i.e. the entirety of chemical processes that take place in a living organism to enable life processes. Metabolic disorders can cause a variety of Diseases in Dogs and cats. disorders. Specific inflammatory markerInflammatory markers are substances in the blood that increase in concentration when there are inflammatory conditions in the body. They help with the diagnosis and monitoring of inflammatory conditions in dogs and cats. such as C-reactive proteinProteins are large molecules made up of amino acids and play an essential role in almost all biological processes. They are necessary for building body tissue, the function of the immune system, and as enzymes for metabolic reactions. or serum-Amyloid A can support the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients..
In case of unclear cause, further investigations are indicated. Imaging procedures such as X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions. can provide clues to pneumonia, a foreign body, or tumors. Sonography / ultrasoundSonography / ultrasound, also called ultrasound examination, is an imaging technique that uses sound waves to create images of the inside of the body. It is used for diagnostic purposes in veterinary medicine, including the examination of soft tissue structures. is suitable for assessing the abdominalThe term "abdominal" refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. organs and for detecting fluid accumulations or abscesses. In complex cases, CT or MRI can provide additional information.
Microbiological examinations include blood cultures in case of suspected bacteremia as well as urine, stool, or tissue samples, depending on the clinical suspicion. PCR tests enable direct pathogenA pathogen is a microorganism or virus that can cause disease in its host. Pathogens include bacteria, viruses, fungi, and parasites. detection in viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. or special bacterial infections. Serological tests can detect antibodyAn antibody is a protein produced by the immune system to recognize and bind specific antigens. By binding to the antigen, antibodies can help destroy or neutralize it. against specific pathogens.
In case of therapy-resistant fever of unclear origin, more invasiveInvasive describes medical procedures or pathogens that enter the body or penetrate tissue. In medicine, invasive procedures can range from minimally invasive techniques to open surgery. diagnostic measures such as bone marrow biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions., lymph node biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions., or an explorative laparotomyA laparotomy is a surgical procedure in which the abdominal cavity is opened through a large incision in the abdominal wall. This allows direct access to the abdominal organs for diagnostic or therapeutic purposes. may be necessary.
Further veterinary measures
If the symptoms persist for more than a day or additional symptoms such as Drowsiness, Skin changes, Vomiting, DiarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems., and others occur, do not wait for the fever to disappear on its own, but introduce it to a veterinarian.
Fever is not a disease, but a symptom. Accordingly, the veterinarian will clarify the cause of the fever through a physical examination, laboratory diagnostics, and possibly further procedures such as X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions., ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow., etc.
The treatment of sudden high fever in dogs and cats follows a multi-stage approach that includes both symptomatic therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. and treatment of the underlying cause.
Emergency measures for critical fever (> 41 °C) are initially aimed at lowering body temperature. Controlled passive cooling can be achieved by placing damp cloths on the paws, armpits, and groin. Active cooling measures such as cool (not cold) water baths should be used with caution and only under veterinary supervision, as cooling too quickly can lead to circulatory problems. Fans can support evaporative cooling. The target temperature is about 39 °C, after which cooling should be stopped to avoid hypothermia.
SupportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. primarily includes fluid therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions., which is essential for fever patients. Intravenous infusions with isotonic crystalloids compensate for fluid losses and support circulatory function. The infusion rate is individually adjusted to the hydration status and body weight. In severe cases, oxygen therapy may be necessary to support the increased metabolicMetabolic refers to metabolism, i.e. the entirety of chemical processes that take place in a living organism to enable life processes. Metabolic disorders can cause a variety of Diseases in Dogs and cats. rate.
AntipyreticAntipyretic drugs are medications used to reduce Fever. They work by acting on the heat-regulating center in the brain, thus regulating body temperature. These medications can be used in dogs and cats to reduce Fever, which is often a symptom of an infection or inflammation. (fever-reducing) drugs are used in a targeted manner. Non-steroidalNon-steroidal refers to medications or substances that are not steroids and often have anti-inflammatory, analgesic, or antipyretic effects. They are used in dogs and cats to treat Pain and Inflammatory conditions. anti-inflammatory drugsAnti-inflammatory drugs are medications that reduce inflammation. They can be divided into nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids and are used in dogs and cats to reduce Inflammatory conditions and Pain. such as meloxicam or carprofen may be indicated at temperatures above 40 °C or in cases of severe discomfort. It is important that these drugs are administered only under veterinary supervision, as they can have side effects on the kidneys and gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract. Paracetamol is absolutely contraindicated for cats and can be fatal.
The causal therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. depends on the underlying cause. In bacterial infections, antibiotics are used, initially often as a broad-spectrum antibioticA broad-spectrum antibiotic is an antibiotic that is effective against a wide range of bacterial pathogens, including both Gram-positive and Gram-negative bacteria. It is often used when the specific pathogen of an infection has not yet been identified., later specifically according to an antibiogram. ViralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. infections usually require symptomatic treatment; antiviral drugs are available for certain pathogens. Parasitic diseases are treated with specific antiparasiticsAntiparasitics are medications or substances used to treat parasitic infestations, such as worms, protozoa, and ectoparasites. They work by killing the parasites or inhibiting their growth.. Immune-mediated diseases often respond to corticosteroidsCorticosteroids are a class of steroid hormones that occur naturally in the body and can also be produced synthetically. They have anti-inflammatory and immunosuppressive properties and are used in veterinary medicine to treat a variety of conditions. or other immunosuppressants.
In severe cases, intensive care with continuous monitoring of vital parameters may be necessary. Monitoring includes regular temperature checks, ECG monitoring, and blood pressure measurements.
Prognosis and aftercare
The prognosis for sudden high fever depends largely on the underlying disease, the height of the fever, the duration of the condition, and the time of the start of therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions.. In general, the earlier the treatment begins, the better the chances of success.
In bacterial infections, the prognosis is usually good if adequate antibiotic therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. is started in time. ViralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. diseases have different courses – while some, like uncomplicated cat cold infections, have a good prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop., others, such as parvovirus or FIP, can be more serious. In immune-mediated diseases, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. depends on the response to immunosuppressiveImmunosuppressive agents are medications or substances that specifically suppress the activity of the immune system. They are used in dogs and cats to treat autoimmune diseases, allergies, and to prevent rejection reactions after transplants. therapies.
It becomes critical at temperatures above 41 °C for several hours, as irreversible organ damage is likely. The central nervous systemThe CNS (central nervous system) consists of the brain and spinal cord. It is responsible for processing information and controls most functions of the body and behavior., liver, kidneys, and gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract are particularly at risk. Prolonged hyperthermiaHyperthermia refers to an elevated body temperature beyond the normal range. In dogs and cats, this can be caused by overheating, Fever, or certain diseases, and often requires urgent medical attention. can lead to coagulationCoagulation is the process of blood coagulation, in which liquid blood is transformed into a solid clot. This process is crucial for stopping Bleeding and promoting wound healing. disorders and, in the worst case, to multipleMultiple means manifold or repeated and is used to describe conditions or events that occur in multiple instances or at different locations. In veterinary medicine, this may indicate multiple lesions, tumors, or other pathological changes. organ failure.
Aftercare following a Fever episode is crucial for a full recovery. During the convalescence phase, the animal should be kept in a quiet, stress-free environment. Physical exertion should be avoided for at least one week after the Fever subsides to avoid putting additional strain on the organism.
Nutrition plays an important role in the recovery phase. Easily digestible, high-quality food in small, frequent portions supports regeneration. If there is a loss of appetite, feed additives or a special diet can be offered. Adequate hydration remains important even in the aftercare phase.
Check-up examinations are important to monitor the healing process and detect relapses early. Depending on the underlying disease, laboratory tests, imaging procedures, or specific tests may be necessary. The schedule for these follow-up checks is determined individually; typically, the first check takes place after 3–7 days.
Particular attention should be paid to recurring Fever episodes, which may indicate chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. infections, autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus., or neoplasms and require further diagnostics.
Summary
Sudden high Fever in dogs and cats is a serious condition that requires quick action. With temperatures above 40 °C, the body reacts to various triggers, with infections being the most common cause. The symptomatologySymptomatology refers to the entirety of symptoms associated with a particular disease or condition. It describes how a disease manifests itself externally. includes lethargy, loss of appetite, increased respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. and heart rate, as well as warm mucous membranes, and can be supplemented by specific signs depending on the underlying disease.
The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. begins with the correct temperature measurement and includes a systematic clarification through clinical examination, laboratory diagnostics, and imaging procedures. The therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. follows a multi-stage approach with emergency measures to lower the temperature in critical Fever, supportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. treatment through fluid therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. and targeted use of antipyreticAntipyretic drugs are medications used to reduce Fever. They work by acting on the heat-regulating center in the brain, thus regulating body temperature. These medications can be used in dogs and cats to reduce Fever, which is often a symptom of an infection or inflammation. drugs, as well as causal therapy of the underlying disease.
The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. depends largely on the cause, the Fever height, and the time of the start of therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions.. Aftercare with adapted housing, special nutrition, and regular check-ups is crucial for complete recovery and to avoid relapses.
Pet owners should know that Fever is not a disease in itself, but a symptom and an important defense reaction of the body. Nevertheless, sudden high Fever requires veterinary attention, as it can indicate serious underlying diseases and, in extreme values, even has organ-damaging effects. Early detection and treatment are the key to successful therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions..
Outlook on current research
Veterinary medicine is continuously developing new approaches to the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. of febrile diseases in small animals. Current research focuses on several promising areas.
In the field of diagnostics, point-of-care tests are revolutionizing rapid diagnostics. These enable the detection of specific pathogens or inflammatory markerInflammatory markers are substances in the blood that increase in concentration when there are inflammatory conditions in the body. They help with the diagnosis and monitoring of inflammatory conditions in dogs and cats. directly in the practice within minutes. New molecular biological methods such as multiplex PCR can test for multipleMultiple means manifold or repeated and is used to describe conditions or events that occur in multiple instances or at different locations. In veterinary medicine, this may indicate multiple lesions, tumors, or other pathological changes. pathogens in one sample at the same time, which speeds up the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients.. The development of specific biomarkers for various Fever causes could enable a more precise differentiation in the future.
In therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions., new antimicrobialAn antimicrobial substance is an agent that serves to inhibit the growth of microorganisms such as bacteria, viruses, fungi, and protozoa, or to kill them. Antimicrobials are frequently used to treat infections. substances are being researched that are also effective against multi-resistant pathogens. Targeted immune modulation through specific biologics represents a promising approach for immune-mediated Fever causes. For viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. diseases such as FIP in cats, significant progress has been made in recent years with new antiviral substances.
Telemedicine is also gaining importance in veterinary medicine. Remote monitoring systems enable continuous temperature measurement and vital parameter monitoring at home, which can be particularly helpful for chronically ill animals or after Fever episodes. These technologies could enable earlier intervention in the future.
Another research focus is on a better understanding of thermoregulation in different animal species and breeds. Genetic factors that influence the susceptibility to certain febrile diseases are increasingly being identified, which could enable individualized prevention and treatment strategies in the future.
The One Health Initiative, which emphasizes the connection between animal, human, and environmental health, is gaining importance in the research of febrile diseases. Many pathogens that cause Fever in pets have zoonotic potential or are transmitted by vectors whose spread is influenced by climate change.
These research approaches promise improved diagnostics and therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. for febrile diseases in dogs and cats in the coming years, which will ultimately lead to a better prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. and quality of life for our animal companions.
Frequently asked questions (FAQs)
- From what temperature should I take my pet to the vet?
A visit to the vet is advisable at temperatures above 39.5 °C. Temperatures above 40 °C are an emergency and require immediate veterinary assistance. - Can I give my animal antipyretics myself?
No, human fever remedies can be dangerous or even fatal for animals. Only administer medication as directed by a veterinarian. - How do I measure the temperature of my pet correctly?
RectalRectal refers to anything involving the rectum, including administering medication or performing examinations via the anus. measurement with a digital thermometer is the most accurate. Carefully insert the lightly oiled thermometer 2–5 cm (depending on the size of the animal) into the rectum and wait until the measured value is stable. - How can I help my feverish animal at home?
Offer fresh water, provide a quiet environment, and carefully cool paws and groin with damp cloths if the fever is very high. But always seek veterinary advice. - Can stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats. fever in my pet?
Stress alone rarely causes real fever, but can lead to a slight increase in temperature. Persistent temperature increases usually have other causes. - How long does it take for antibiotics to work in a feverish animal?
As a rule, a decrease in fever should be observed within 24–48 hours after the start of effective antibiotic therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions.. - Can my animal die of fever?
Extremely high fever (over 42 °C) can be life-threatening and lead to organ damage. However, it is not the fever itself, but predominantly the underlying disease that is the real danger. - Why is my cat harder to recognize with fever than my dog?
As natural prey, cats show symptoms of illness less clearly and often hide when they are unwell, which can make early detection more difficult. - Can I prevent fever?
Regular vaccinations, parasiteA parasite is an organism that lives on or in another living being (the host) and feeds at its expense. Parasites can cause a variety of diseases in animals and humans. preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring., and good hygiene can prevent many fever-causing diseases. Regular veterinary check-ups help to identify problems early. - Is it normal for my animal to develop a slight fever after vaccinationVaccination is the process of administering a vaccine to develop immunity against a specific infectious disease. It is one of the most effective methods of prevention of infectious diseases.?
A mild increase in temperature (up to about 39.5 °C) can occur in the first 24–48 hours after vaccinationVaccination is the process of administering a vaccine to develop immunity against a specific infectious disease. It is one of the most effective methods of prevention of infectious diseases. and is mostly harmless. Higher or longer-lasting fever should be clarified by a veterinarian.
Literature
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- Lappin, M. R., Blondeau, J., Boothe, D., Breitschwerdt, E. B., Guardabassi, L., Lloyd, D. H., Papich, M. G., Rankin, S. C., Sykes, J. E., Turnidge, J., & Weese, J. S. (2021). Antimicrobial use guidelines for treatment of respiratory tract disease in dogs and cats: Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases. Journal of Veterinary Internal Medicine, 35(1), 279–294. https://doi.org/10.1111/jvim.15793
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- Ramsey, I. K., & Tasker, S. (2022). Fever. In S. J. Ettinger, E. C. Feldman, & E. Côté (Hrsg.), Textbook of veterinary internal medicine (8. Aufl., S. 142–146). Elsevier.
- Sykes, J. E. (2023). Canine and feline infectious diseases (2nd ed.). Elsevier Saunders.