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Canine Influenza (Dog Flu Viral Infection) in Dogs

Occurrence: rarer
Location of illness: General/Whole body

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza, also known as dog flu, is a contagiousContagious means infectious. Diseases that can easily be transmitted from one animal to another or from animals to humans are referred to as contagious. respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. disease in dogs caused by influenza viruses. The disease is similar to the human flu and primarily affects the respiratory tractThe respiratory tract includes the organs and structures involved in the breathing process, including the nose, pharynx, larynx, trachea, bronchi, and lungs..

The most important facts at a glance

Canine influenza, also called dog flu, is mainly caused by the influenza viruses H3N8 and H3N2, which originally come from horses and birds, respectively. Transmission occurs via droplet infectionDroplet infection refers to the transmission of pathogens through small droplets of liquid that are released into the air when infected people Cough, Sneeze, or talk and are inhaled by other people., such as through Coughing or Sneezing, as well as 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. surfaces. Since most dogs do not have natural immunityImmunity is the body's ability to protect itself against infections, diseases, or foreign substances. It can be natural, as with innate immunity, or acquired, as with adaptive immunity, which develops after an infection or vaccination., the 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. rate is high. Symptoms include conjunctivitis, nasalNasal refers to the nose and nasal cavities. In veterinary medicine, this can involve examinations, treatments, or diseases affecting the nose of dogs and cats. discharge, Cough, Sneezing, and Fever. 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. is made through clinical symptoms and specific tests, such as polymerase chain reaction (PCR). X-rays can be helpful if Pneumonia is suspected.

Treatment focuses on relieving symptoms, as no specific antiviral drugs exist. Cough suppressants and 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. can be used for relief, while antibiotics are necessary for secondary bacterial infections. Rest and adequate hydration are crucial. 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. is good if the disease is detected early, although complications such as Pneumonia can prolong recovery. Young, old, or immunocompromised dogs are particularly at risk. The most effective preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. is 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., supplemented by hygiene measures and isolation of infected dogs. Research aims to improve vaccines and diagnostic tests as well as understand disease spread.

Causes

Canine influenza is mainly caused by two subtypes of influenza viruses: H3N8 and H3N2. These viruses are members of the Orthomyxoviridae family, which is also responsible for influenza in other animals and humans. Originally from horses, the H3N8 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. has adapted to dogs and was first identified in the USA in 2004. The H3N2 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., on the other hand, originated in birds and was first detected in Asia in 2007.

CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza is mainly transmitted via droplet infectionDroplet infection refers to the transmission of pathogens through small droplets of liquid that are released into the air when infected people Cough, Sneeze, or talk and are inhaled by other people.. This means that the viruses are spread through coughing, sneezing, or direct contact with infected dogs. 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. surfaces, such as food bowls or toys, can also be a source of 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 viruses are relatively robust and can survive in the environment for several hours under favorable conditions.

An important factor in the spread of dog flu is the high 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. rate. Since it is a relatively new 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., most dogs have no natural immunityImmunity is the body's ability to protect itself against infections, diseases, or foreign substances. It can be natural, as with innate immunity, or acquired, as with adaptive immunity, which develops after an infection or vaccination. to it, which makes it easier for the 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. to spread rapidly in a dog populationIn veterinary medicine, the term population refers to a group of animals of a particular species living in a specific geographic area or environment..

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

The symptoms of canineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza are similar to those of a typical respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. 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. and can vary in severity. The most common signs include Cough, which may be dry or moist, Sneezing, and nasalNasal refers to the nose and nasal cavities. In veterinary medicine, this can involve examinations, treatments, or diseases affecting the nose of dogs and cats. discharge. These symptoms can easily be confused with kennel cough, which also occurs in dogs.

Affected dogs may also develop Fever, ranging from mild to high. In some cases, the Fever can rise up to 41°C. Other symptoms include Lethargy, loss of appetite, and, in severe cases, RespiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress. In some dogs, the 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. can lead to Pneumonia, which requires more intensive treatment.

The incubation periodThe incubation period is the time between infection with a pathogen and the appearance of the first symptoms. This period can vary depending on the pathogen and individual immune response. for canineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza is usually two to four days after 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.. Dogs are already contagiousContagious means infectious. Diseases that can easily be transmitted from one animal to another or from animals to humans are referred to as contagious. during this time, even if they do not yet show any symptoms, which makes it difficult to contain the disease.

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 canineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza is based on a combination of clinical symptoms and laboratory diagnostic tests. Since the symptoms of dog flu are similar to those of other respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. diseases, it is important to perform specific tests to determine the exact cause.

A veterinarian can take samples of nasalNasal refers to the nose and nasal cavities. In veterinary medicine, this can involve examinations, treatments, or diseases affecting the nose of dogs and cats. or pharyngeal secretions to identify the 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. using polymerase chain reaction (PCR), a sensitive and specific method for detecting 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. RNA. Blood tests can also be performed to detect antibodies against the 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., indicating a current or past 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..

In some cases, chest X-rays may be necessary, especially if Pneumonia is suspected. These images help determine the extent of the respiratory disease and rule out other possible causes of the symptoms.

Therapy

The treatment of canine influenza focuses primarily on relieving symptoms and supporting the dog’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body.. There are no specific antiviral drugs approved for dog flu, so therapy is usually symptomatic.

Cough suppressants may be prescribed to relieve the urge to cough and provide some relief to the dog. 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. (NSAIDsNSAID (non-steroidal anti-inflammatory drug) stands for non-steroidal anti-inflammatory drugs, a class of medications used to relieve pain, reduce inflammatory conditions, and lower fever without using steroidal agents. They are a commonly used pain reliever in veterinary medicine.) can also be used to reduce fever and reduce inflammatory conditions. In cases where a secondary bacterial 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. is suspected, antibiotics may be necessary.

Rest and adequate fluid intake are crucial for recovery. In severe cases, especially if Pneumonia is present, inpatient treatment at a veterinary hospital may be necessary to ensure intensive care, including oxygen 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..

Prognosis and follow-up care

The prognosis for canineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza is good in most cases, especially if the disease is detected and treated early. Most dogs recover completely within two to three weeks, although the cough may persist longer in some animals.

In dogs that develop Pneumonia or have other serious complications, recovery may take longer, and there is a higher risk of permanent damage to the respiratory tractThe respiratory tract includes the organs and structures involved in the breathing process, including the nose, pharynx, larynx, trachea, bronchi, and lungs.. However, canineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza rarely leads to Death, provided the dog receives veterinary care in good time.

Very young, very old, or immunocompromised dogs are particularly at risk, with a higher risk of more severe disease progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms..

Prevention

The most effective method of preventing canineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza is 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.. Vaccines are available against both main strains (H3N8 and H3N2), which can significantly reduce the risk of infection. 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. is particularly recommended for dogs that are in close contact with other dogs, such as in animal shelters, dog boarding kennels, or at dog shows.

In addition to 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., it is important to practice good hygiene measures. This includes regularly cleaning and disinfecting items used by 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. dogs, as well as avoiding direct contact with infected animals.

Pet owners should watch for signs of a respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. illness in their dogs and consult a veterinarian early if 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. is suspected to prevent the spread of the 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.. Isolating infected dogs is also an important step in protecting other animals.

Outlook on current research

Canine influenza, also known as dog flu, is a relatively new disease that was first identified in the early 2000s in the USA. Since then, scientific research has made significant progress in investigating the causes, transmission routes, and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies. A major focus of current research is the development of more effective vaccines. While vaccines are already available, researchers are working to improve 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. and extend the duration of protection. Work is also underway to develop vaccines against different strains of the 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. to provide broader protectionProtection refers to safeguarding against diseases or harm. In veterinary medicine, this can include protecting animals through vaccinations, the use of parasite control products, or providing a safe environment..

Another important aspect of research is monitoring and understanding disease spread. Scientists analyze genetic variations of the 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. to track its evolution and mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits.. This information is crucial to better assess the risk of outbreaks. In addition, it is being investigated how environmental influences and contact with other animals influence the transmission dynamics.

There are also efforts to explore the role of carrier animals and intermediate hosts. Although dogs are the main hosts, there is evidence that other animals, such as cats, can also be infected. This raises questions about how the disease can be transmitted between different species and what role these animals might play in the spread of the 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..

Another area of research focuses on improving diagnostic tools. Rapid and accurate diagnostic tests are crucial to quickly detect and contain outbreaks. Scientists are working to develop tests that not only provide faster results but are also more sensitive to detect infections early.

In addition, research is being conducted on how the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. of dogs responds to the 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.. These studies aim to understand the mechanisms that lead to severe disease progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. and to develop therapeutic approaches that can alleviate symptoms and accelerate recovery. There is also interest in identifying genetic factors that could make certain dogs more susceptible to severe courses.

Another topic in current research is the investigation of treatment options. While the disease is self-limitingSelf-limiting conditions are conditions that resolve on their own without medical intervention. In dogs and cats, mild viral infections or gastrointestinal disturbances can often be self-limiting. in many cases, there are more severe cases that require medical intervention. Researchers are investigating antiviral drugs and other treatment strategies to alleviate symptoms and support recovery.

Collaboration between veterinarians, epidemiologists, and virologists is crucial to address the challenges of canineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza. By sharing information and coordinating research efforts, scientists hope to deepen the understanding of this disease and develop more effective preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. and treatment strategies.

Overall, research on canineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza is a dynamic and rapidly evolving field. The progress made in recent years offers hope that new insights and technologies will soon lead to better control of the disease.

Frequently asked questions (FAQs)

What is CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza? CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. influenza is a highly contagiousContagious means infectious. Diseases that can easily be transmitted from one animal to another or from animals to humans are referred to as contagious. respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. disease caused by influenza viruses that specifically affect dogs. It is similar to the human flu and can cause symptoms such as Cough, Fever, and nasal discharge.
How is CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza transmitted? The virus is mainly transmitted through direct contact with infected dogs or 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. surfaces. Droplet transmission through Coughing or Sneezing is also a common route of spread.
What symptoms does a dog with CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza show? The most common symptoms include persistent Cough, Fever, runny nose, Lethargy, and loss of appetite. In severe cases, Respiratory distress and Pneumonia can occur.
Can humans be infected by dogs with CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza? To date, there is no evidence that canine influenza can be transmitted to humans. The disease mainly affects dogs.
Is there a vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens. against CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza? Yes, there are vaccines that can help protect dogs from 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. with the 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.. Veterinarians can recommend the right vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens. based on your dog’s 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. and risk of 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..
How is CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza diagnosed? 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. is usually made through a combination of clinical symptoms and laboratory tests. Swabs from the dog’s nose or throat can be taken to confirm the 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..
How is CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza treated? Treatment often focuses on relieving symptoms. Rest, hydration, and in some cases medications to control Cough and Fever may be recommended. Antibiotics are used for secondary bacterial infections.
How can you prevent a dog from becoming infected with CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza? To prevent 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., contact with infected dogs should be avoided. Regular cleaning of surfaces and vaccinations can also reduce the risk.
Are there dogs that are particularly susceptible to CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza? All dogs can be infected, but puppies, older dogs, and dogs with weakened immune systems have a higher risk of severe courses.
How long does it take to recover from CanineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. Influenza? Recovery time can vary, but most dogs recover within two to three weeks. In more severe cases, recovery may take longer and may require veterinary care.