Top 9 most Common Dog Diseases (2025)

Knowledge ofthe most common dog diseases can come in very handy if you are a dog owner. As your dog can suffer from different diseases. Once you observe abnormal symptoms or behavior in your dog you must consult your veterinarian. This article will explain the causes, symptoms, and different treatment options available for common dog diseases.

Canine distemper is a highly contagious and fatal viral disease of dogs caused by the canine distemper virus. Unvaccinated or incompletely vaccinated puppies (3 to 6 weeks) are at great risk. Infected animals directly transmit CD, or contaminated surfaces indirectly spread it. The virus primarily affects the gastrointestinal, respiratory, and nervous systems. About 50 percent of dogs cannot survive, but treated dogs develop lifelong immunity with permanent nervous damage.

Clinical signs of the virus vary dramatically depending upon the strain of the virus, dog breed, and immune status.

Symptoms include

• Fever
• Reduced Appetite
• Bilateral nasal and ocular discharge
• Conjunctivitis
• Cough
• Vomiting
• Diarrhea
• Dehydration
• Seizures
• Behavioral Changes
• Paralysis

Diagnosis is based on a combination of clinical signs and laboratory tests.

Treatment involves the administration of antidiarrheals, antiemetics, and antipyretics, and the provision of electrolyte solutions. If the dog shows nervous signs, administer an anticonvulsant. The best way to protect your dog from CD is by vaccination.

Canine parvo, commonly known as “parvo, is another highly contagious canine disease. Puppies between 6 weeks and 20 weeks are most susceptible. The feces of infected dogs can spread viruses. It can survive in the environment for up to 1 year under favorable conditions. Untreated cases report a 91 percent mortality rate.

Signs and Symptoms includes

• Fever
• Vomiting
• Diarrhea (sometimes bloody)
• Rapid heart rate
• Difficulty in breathing
• Abdominal tenderness
• Tremors and seizures

The veterinarian will confirm the diagnosis by observing clinical signs and performing fecal examinations, diagnostic imaging, and laboratory tests.

There is no specific treatment for parvo. Veterinarians treat dogs by initiating supportive therapy combined with symptomatic treatment. Since parvovirus is a highly deadly disease, therefor veterinarians include its vaccination in core dog vaccinations, making it the most effective preventive measure.

Leptospirosis is a widespread zoonotic bacterial infection caused by the spirochete bacteria Leptospira interrogan, a species of Leptospira. It’s persistently shed in the urine of infected animals, thus acting as a means of further spread of the disease. Like parvovirus, Leptospira can survive in the environment for many months. Stagnant water and wet environments provide favorable environments for the months-long survival of bacteria.

Symptoms include

• Reduced Appetite
• Polyuria (increased urination)
• Polydipsia (increased drinking)Diarrhea (sometimes with blood)
• Excessive panting
• Difficulty breathing
• Muscle tenderness
• Petechiae (pinpoint bleeding seen along gums)
• Jaundice
• Weight loss

Leptospirosis can damage the liver and kidneys of your pet. Diagnosis starts with a discussion of clinical signs and symptoms. Blood tests like CBC and urine analysis should be performed for further confirmation. The veterinarian will administer antibiotics like penicillin or doxycycline. Fluid therapy is critical, along with other supportive therapy.

Lyme disease, or Lyme borreliosis, is caused by a spirochete, Borrelia burgdorferi, which is transmitted by the black-legged tick, also called the deer tick. Also Humans can develop Lyme disease from the infected tick. Once this organism enters the blood circulation, it localizes in joints and kidneys.

Lyme disease is notoriously difficult to diagnose because most infected dogs show no signs of illness. Dogs might usually take 2-5 months to show symptoms.

Common symptoms shown by dogs include

• Fever
• Inappetence
• Dehydration
• Arthritis and lameness
• Swollen, warm, painful joints

For the diagnosis of Lyme disease, the veterinarian will perform the C6 test and the Quant C6 test along with physical findings and antibody titer.

This disease is treated with the administration of antibiotics for at least 30 days. Antibiotics administered include doxycycline and amoxicillin. To protect your dog from Lyme disease, tick control is a must. For this purpose, you can use tick-preventive products prescribed by your veterinarian.

Giardiasis is a gastrointestinal disease of dogs often causing diarrhoea and is not fatal. Many dogs are asymptomatic. It’s caused by giardia, a single-celled parasite. It’s found in two forms: feeding form, or trophozoite, and cysts. Cysts are found in the external environment, secreted from the feces of infected animals. Dogs can become infected by sniffing the cysts or drinking contaminated water.

Common signs and symptoms include

• Intermittent diarrhoea
• Vomiting
• Weight loss
• Abdominal discomfort

Giardiasis is diagnosed with multiple fecal tests for the identification of giardia cysts. Treatment includes administration of metronidazole and fenbendazole in combination for 3 to 10 days. Fluid therapy can be done in case of excessive fluid loss. Regular bathing is recommended because cysts are shed in the dog’s feces.

Cleaning and disinfecting dog bedding from cysts should be performed. Prevention includes vaccination against giardia and parasite-prevention medications.

Heartworm disease is a potentially fatal condition in dogs caused by the parasitic worm Dirofilaria immitis. It is a one-foot-long, slender-shaped worm that can clog blood vessels and the heart, causing heart failure and ultimately the death of the animal.

Dogs are definite hosts of heartworm as they mature into their adult form in their body. Mosquitoes act as intermediate hosts, and their bites are the primary source of infection for dogs.

Symptoms include

• Cough
• Lethargy
• Exercise intolerance
• Dark Urine
• Heart Failure

Veterinarians divide heartworm disease into four classes based on its severity. Class One is the mildest form, while Class Four, also called Caval syndrome, represents the severe form of the disease. Veterinarians diagnose heartworm disease once your dog reaches 7 months old. Diagnosis is based on blood tests, chest radiographs, and echocardiograms.

The treatment of choice for heartworm is melarsomine injections. Three injections of melarsamine are given. The first injection is followed by one month of complete rest and the remaining two injections after one month for two consecutive days. Doxycycline and prednisone can also be given. To protect your dog from heartworm, prevention is key. Avoid your dog’s exposure to mosquitoes and regularly use market-available heart prevention, especially if you are living in an endemic area.

Cataracts are the opaqueness or opacity of the eye lens. It results from disruptions in water balance, protein content, or normal fiber arrangement of the eye lens. Eyes appear cloudy and milky.

The eye lens focuses light on the retina, therefore it is critical for vision. The most common causes of cataracts are hereditary diseases. They can also develop due to diabetes mellitus.

Cataracts can be classified into four stages.

• Incipient
• Immature
• Mature
• Hypermature

Cataracts can cause blindness in dogs. The veterinarian will perform the Schirmer tear test and fluorescein stain test for the diagnosis. Canine cataract surgery is the only treatment option, and mostly it can be done without further complications.

Fungal infections are less common than viral or bacterial infections. They can be localized or systemic, and veterinarians use antifungal drugs to treat them.

Fungal infections have two types: systemic and local. The systemic fungal infection affects your major body organs, while the latter one mainly affects the skin and external extremities.

Fungi mainly affects three types of pets, which are young, large-breed animals with weak immune systems and the third one that is taking cyclosporine drug.

Aspergillosis, Malassezia, Histoplasmosis, Cryptococcosis, and Blastomycosis mostly cause fungal infections in dogs.

Signs and symptoms in dogs include

• Circular hair loss
• Redness and itchiness
• Brittle or misshaped claws

Diagnosis depends on history and clinical signs. Wood’s lamp test and fungal culture can help in definitive diagnosis. Treatment involves topical, oral, and systemic administration of antifungal drugs like fluconazole, ketoconazole, and itraconazole.

Ear infections are very painful and irritating for dogs. They are more common in breeds with long, floppy, and hairy ears. There are mainly three types of ear infections. Otitis externa is an infection of the outer ear, and it’s the most common type. Otitis media and otitis interna are infections of the middle and inner ear, respectively. Although they are less common than otitis externa, they can be more severe.

Yeasts and bacteria normally reside in dog ears, but ear infections can occur when their balance is disturbed. Other causes include moisture, allergies, autoimmune diseases, injury to the ear canal, foreign bodies, and endocrine diseases.

Common symptoms of ear infections include

• Head shaking and head rubbing
• Red and Painful Ears
• Foul odor from ears
• Smelly discharge
• Crusting or scabs

The veterinarian will first examine the ear with an otoscope and use cytology and cell culture tests for further diagnosis.

Treatment starts with thoroughly cleaning the ears of the dog. Eardrops and topical ear applications will resolve the infection. Veterinarians can also use oral antibiotics. Regular ear cleaning is important to protect your dog from infections with veterinary cleaners.

Here are some practical tips to avoid diseases in dogs:

• Keep your pet up to date on vaccinations.
• Visit your veterinarian at least once a year to help with the early detection of diseases and suggestions from the veterinarian.
• Spay or neuter your pet to avoid cancer and reproductive issues. Furthermore, it also keeps in check the pet population.
• Provide a balanced diet and do not overfeed.
• Regularly deworm your pet from internal parasites.
• Maintain good hygiene by regularly bathing and clearing the pet’s ears.
• Brush your dog’s teeth daily if needed; otherwise dental scale your dog.
• Daily walks and exercise keep your dog fit and active.

These are the most common dog diseases, and as a dog owner, you always want your pet healthy. Therefore, dog vaccinations are very important, so do not procrastinate. Observe the dog’s behavior, and if you notice something abnormal, visit your veterinarian. If you’re thinking of buying a new dog or curious to understand different cat diseases, then my posts will be best for you.