Common Pet Diseases | Cat & Dog Symptoms, Prevention & Treatment Guide

*Disclaimer: The following information is for reference only. If your pet shows one or more of these symptoms, please consult a veterinarian immediately. Do not delay treatment.

Pets are cherished family members, and understanding common diseases and their symptoms is essential for every pet owner. Whether you have a cat or dog, early recognition of disease signs and seeking professional veterinary care can significantly improve treatment success rates, allowing your beloved pet to enjoy a longer, healthier life with you. This comprehensive guide covers the most common health problems in cats and dogs, their symptoms, prevention methods, and treatment options.

Parasitic Diseases

Parasites are one of the major threats to cat and dog health, divided into external parasites (such as fleas and ticks) and internal parasites (such as heartworms and intestinal parasites). These common diseases not only affect pet health but some can also be transmitted to humans.

Flea Infestation

Fleas are the most common external parasites in cats and dogs. A single flea can lay up to 50 eggs per day, rapidly multiplying throughout the home environment. Fleas not only cause skin itching but their saliva also triggers allergic dermatitis, severely impacting pets' quality of life.

Symptoms: Frequent scratching, red and inflamed skin, hair loss (especially on the lower back), visible small black flea feces on the skin, restlessness and agitation, severe infestations can cause anemia.

Prevention: Year-round flea prevention products are key, including topical spot-on treatments, oral medications, or flea collars. Regularly wash pet bedding and blankets. Vacuum your home frequently, paying special attention to carpets and sofa crevices where flea eggs can hide.

Treatment: Use veterinarian-recommended flea treatment products on your pet while thoroughly cleaning the home environment. Since the flea life cycle can span several months, continue prevention for at least 3 months to completely eliminate the infestation.

Ticks

Ticks are quite common in Hong Kong's countryside, particularly in grassy areas and hiking trails. Ticks attach to pet skin to feed on blood and can transmit serious blood-borne diseases such as Ehrlichiosis and Babesiosis, potentially causing acute anemia and even death.

Symptoms: Visible blood-sucking parasites attached to the skin, red and inflamed skin, anemia symptoms (pale gums, weakness), fever, decreased appetite, severe cases may show jaundice.

Prevention: Regular use of tick prevention products (topical treatments or oral preventatives). Thoroughly check your pet's entire body after outdoor activities, especially ears, between toes, armpits, and groin areas. Avoid taking pets into areas with dense vegetation.

Treatment: Remove ticks using specialized removal tools to extract them completely. If your pet has contracted tick-borne disease, antibiotic treatment is required, and severe anemia cases may need blood transfusions.

Heartworm Disease (Dogs)

Heartworm disease is a potentially fatal parasitic disease transmitted through mosquito bites, primarily affecting dogs. Adult heartworms can grow up to 30cm long, residing in the heart and pulmonary arteries, severely affecting heart and lung function. Hong Kong's humid, mosquito-prone climate makes heartworm infection risk considerably high.

Symptoms: Early stages may be asymptomatic, lethargy, reduced exercise tolerance, persistent cough, difficulty breathing, weight loss, abdominal swelling, congestive heart failure.

Prevention: Monthly heartworm preventative medication is the most effective prevention method. A heartworm test is recommended before starting prevention to confirm your dog is not already infected. Continue prevention year-round without interruption.

Treatment: Treatment is high-risk and expensive, requiring injection of adulticide medication with strict activity restriction during the treatment period. Prevention is far more important than treatment.

Skin Diseases

Skin problems are one of the most common reasons for veterinary visits. Skin diseases can be caused by allergies, infections, parasites, or immune system issues, with symptoms including itching, hair loss, redness, and flaking.

Ringworm (Fungal Infection)

Ringworm is a highly contagious fungal infection caused by dermatophytes, transmissible to other animals and even humans. Both cats and dogs can be infected, with young animals, long-haired breeds, and immunocompromised pets being more susceptible.

Symptoms: Itchy skin, circular or irregular patches of hair loss, scaly and dry skin, redness or gray crusting, excessive dandruff, brittle or deformed nails.

Prevention: Quarantine and observe new pets before introducing them to your household. Maintain environmental cleanliness and regularly wash pet supplies. Avoid contact with stray animals. Support your pet's immune health.

Treatment: Mild infections can be treated with topical antifungal creams or medicated baths. Severe infections require oral antifungal medications, typically for 6-8 weeks. Thorough environmental cleaning and disinfection during treatment is essential to prevent reinfection.

Allergic Dermatitis

Allergic dermatitis is a common chronic skin problem in cats and dogs, caused by food allergies, environmental allergens (such as dust mites, pollen), or flea saliva. Symptoms recur repeatedly and require long-term management.

Symptoms: Persistent itching, red and inflamed skin, hair loss, thickened skin with pigmentation, recurrent ear infections, excessive paw licking, secondary bacterial or yeast infections.

Prevention: Identify and avoid allergens. Use hypoallergenic formulated foods, maintain environmental cleanliness to reduce dust mites. Regular use of flea prevention products.

Treatment: Veterinarians may prescribe antihistamines, steroids, or immunomodulatory medications. Allergy testing can help identify allergens. Severe cases may consider immunotherapy (desensitization therapy).

Kidney Diseases

Kidney disease is one of the major health threats for middle-aged and senior cats and dogs. The kidneys filter waste from the blood and maintain fluid and electrolyte balance. Once kidney function is compromised, toxins accumulate in the body.

Chronic Kidney Disease

Chronic kidney disease is particularly common in cats, with statistics showing over 30% of cats over 7 years old have some degree of kidney problems. Dogs also develop chronic kidney disease, especially senior dogs. This common disease is irreversible, but early detection and proper management can significantly slow disease progression.

Symptoms: Noticeably increased water intake, frequent urination with increased volume, decreased appetite, weight loss, vomiting, lethargy and weakness, mouth ulcers, ammonia-smelling breath, rough coat, sudden blindness from high blood pressure (severe cases).

Prevention: Ensuring adequate hydration is the most important factor in preventing kidney disease. Place multiple water bowls, use water fountains, and feed wet food to increase water intake. Regular health check-ups; pets over 7 years old should have annual blood and urine tests.

Treatment: Treatment goals are to slow disease progression and maintain quality of life, including prescription kidney diets (low phosphorus, high-quality protein), subcutaneous fluid therapy, phosphate binders, anti-hypertensive medications, and medications for anemia. Regular follow-up appointments to monitor kidney function are essential.

Urinary Tract Stones

Urinary stones can occur in the kidneys, ureters, bladder, or urethra. Both cats and dogs can develop this condition, but cats and male dogs with narrower urethras face life-threatening emergencies if stones block the urethra, making urination impossible. Without prompt treatment, this can be fatal.

Symptoms: Blood in urine (pink or red urine), frequent trips to litter box or urination spots with little output, crying or showing pain while urinating, inappropriate elimination, excessive licking of genital area, complete inability to urinate (EMERGENCY).

Prevention: Increasing water intake is key; feeding wet food is better than dry food for preventing stones. Choose appropriately formulated pet food and avoid excessive mineral content. Keep litter boxes clean so cats are willing to urinate normally.

Treatment: Some stones can be dissolved through prescription diets, while others require surgical removal. Urethral obstruction is a medical emergency requiring immediate catheterization. Long-term dietary management is needed after treatment to prevent recurrence.

Dental Diseases

Periodontal Disease

Periodontal disease is an extremely prevalent common pet disease. Studies show over 80% of cats and dogs over three years old have some degree of dental problems. Periodontal disease not only affects oral health but bacteria can also spread through the bloodstream to the heart, liver, and kidneys, causing serious systemic diseases.

Symptoms: Severe bad breath, decreased appetite but interest in food, weight loss, difficulty chewing or eating on one side only, red swollen bleeding or ulcerated gums, loose or missing teeth, excessive drooling possibly blood-tinged, pawing at the mouth.

Prevention: Establishing a tooth brushing routine from a young age is the most effective prevention. Use pet-specific toothbrush and toothpaste, brushing at least 2-3 times per week. Provide dental treats and toys. Have your veterinarian regularly check oral health.

Treatment: Mild periodontal disease can be managed with professional dental cleaning. Severe cases may require extraction of affected teeth. Post-treatment, establishing a daily oral care routine is essential to prevent recurrence.

Infectious Diseases

Infectious diseases are a major threat to young and unvaccinated pets. Through regular vaccination, most serious infectious diseases can be effectively prevented.

Canine Distemper (Dogs)

Canine distemper is a highly contagious viral disease that primarily attacks a dog's respiratory, digestive, and nervous systems. Puppies and unvaccinated dogs are most susceptible, with mortality rates exceeding 50%.

Symptoms: High fever, loss of appetite and lethargy, increased eye discharge with purulent secretions, runny nose and cough, vomiting diarrhea and bloody stool, hardening of paw pads and nose, later stage neurological symptoms (seizures, muscle twitching), loss of coordination and paralysis.

Prevention: DHPP vaccination is the most effective prevention method. Puppies should begin vaccination at 6-8 weeks of age, with boosters every 3-4 weeks until 16 weeks old, then regular boosters thereafter.

Treatment: There is no specific antiviral medication for canine distemper; treatment is primarily supportive. Dogs that recover may have permanent neurological damage.

Canine Parvovirus (Dogs)

Canine parvovirus is an extremely dangerous gastrointestinal infectious disease, primarily transmitted through contact with contaminated feces. The virus attacks the intestinal lining and bone marrow, causing severe gastroenteritis. Unvaccinated puppies have mortality rates up to 90%.

Symptoms: Intermittent vomiting progressively worsening, complete loss of appetite, mild fever or low body temperature, severe depression, severe diarrhea with pale orange feces, distinctive foul-smelling feces, bloody stool, projectile watery diarrhea, severe dehydration.

Prevention: DHPP vaccination is key to prevention. Puppies should avoid public places before completing vaccination series. Parvovirus is extremely hardy in the environment; bleach solution is required for thorough disinfection.

Treatment: Treatment focuses on aggressive supportive care, requiring hospitalization for IV fluids, anti-nausea medication, antibiotics, and nutritional support. Early treatment can improve survival rates to 70-90%.

Feline Infectious Peritonitis (Cats)

Feline Infectious Peritonitis (FIP) was once considered a death sentence, a fatal disease caused by mutation of the feline coronavirus. The good news is that recent medical breakthroughs have brought effective treatment medications, with FIP treatment success rates now reaching 80-90%.

Symptoms: Persistent fever unresponsive to antibiotics, extreme lethargy and depression, loss of appetite and weight loss, visibly distended abdomen (wet FIP with fluid accumulation), difficulty breathing (pleural effusion), vomiting and diarrhea, yellowing of skin and eyes (jaundice), eye inflammation and cloudiness, seizures and hind limb paralysis (neurological FIP).

Prevention: Reduce stress, maintain environmental cleanliness, avoid overcrowded multi-cat environments. Current FIP vaccines have limited effectiveness.

Treatment: GS-441524 oral medication is currently the primary treatment, with a typical course of 84 days (12 weeks). Molnupiravir is another effective oral medication option. Early detection and treatment are crucial for improving success rates.

Cat Flu (Cats)

Cat flu is a common infectious disease in cats, primarily caused by feline herpesvirus and feline calicivirus. Kittens, unvaccinated cats, and immunocompromised cats are most susceptible.

Symptoms: Fever, frequent sneezing, decreased appetite, watery eyes with redness and swelling, runny nose (clear initially becoming thick), nasal congestion with noisy breathing, mouth ulcers (calicivirus), lethargy.

Prevention: Regular vaccination with FVRCP vaccine is the most effective prevention. Maintain environmental cleanliness, reduce stress, avoid contact with sick cats.

Treatment: Supportive care is the mainstay, including maintaining nutrition and hydration, cleaning eye and nasal discharge, using nebulization therapy to relieve congestion. If secondary bacterial infection occurs, veterinarians will prescribe antibiotics.

Metabolic Diseases

Diabetes Mellitus

Diabetes is a common metabolic disease in middle-aged and senior cats and dogs. When the pancreas cannot produce sufficient insulin or the body becomes resistant to insulin, blood sugar cannot be properly regulated. Obese pets, sedentary indoor pets, and older pets have higher diabetes risk.

Symptoms: Increased urination frequency and volume, significantly increased water intake, increased appetite with weight loss, lethargy and decreased energy, weakness in hind legs (especially cats), dull rough coat, slow wound healing.

Prevention: Maintaining a healthy weight is key to preventing diabetes. Provide high-protein, low-carbohydrate diets and encourage physical activity. Regular health check-ups to detect blood sugar abnormalities early.

Treatment: Most diabetic pets require daily insulin injections along with prescription diabetic diets. Veterinarians will teach owners how to monitor blood glucose and administer insulin at home. Regular follow-up appointments to adjust medication dosage are essential.

Hyperthyroidism (Cats)

Feline hyperthyroidism is the most common endocrine disease in senior cats, typically affecting cats over 10 years old. When the thyroid becomes overactive, it produces excess hormones, accelerating the body's metabolism and placing strain on the heart, kidneys, and other organs.

Symptoms: Ravenous appetite with continuous weight loss, hyperactivity and restlessness, irritability and behavior changes, vomiting and diarrhea, increased thirst and urination, thinning or unkempt coat, thickened fast-growing nails, rapid heart rate and heart murmurs.

Prevention: Regular health check-ups can detect problems early. Cats over 10 should have annual blood tests measuring thyroid hormone levels.

Treatment: Treatment options include daily oral anti-thyroid medication, prescription iodine-restricted diet, radioactive iodine therapy, or surgical removal of the thyroid gland. Veterinarians will recommend the most suitable treatment based on the cat's overall health.

Heart Disease

Heart disease is quite common in middle-aged and senior cats and dogs. Small breeds are more prone to mitral valve disease, while large breeds more commonly develop dilated cardiomyopathy. In cats, hypertrophic cardiomyopathy is most common. Heart disease progressively affects the heart's pumping ability, eventually leading to heart failure.

Symptoms: Decreased appetite, reduced stamina and easy fatigue, coughing (especially at night or after exercise), rapid breathing and difficulty breathing, exercise intolerance, abdominal swelling (ascites), pale or bluish mucous membranes, weight loss, fainting episodes.

Prevention: Maintain a healthy weight; avoid obesity which strains the heart. Have regular health check-ups including cardiac auscultation by your veterinarian. Medium to large breed dogs and certain cat breeds may consider periodic cardiac ultrasound examinations.

Treatment: Heart disease cannot be cured but can be controlled with medication. Common medications include diuretics, ACE inhibitors, positive inotropes, and anti-arrhythmic drugs. Combined with a low-sodium diet and moderate exercise. Regular follow-up appointments to monitor the condition are essential.

Joint Disease

Joint disease is a common problem in middle-aged and senior cats and dogs, including osteoarthritis and hip dysplasia. Large breeds and overweight pets are more susceptible to joint problems. Arthritis in cats is often overlooked because cats are adept at hiding pain.

Symptoms: Joint stiffness after activity, difficulty standing especially after rest, decreased activity level, joint swelling, obvious pain when joints are touched, constant licking of affected joints, limping, cats jumping less or avoiding heights, decreased appetite, behavior changes.

Prevention: Maintaining a healthy weight is key to preventing joint problems. Avoid over-exercising or excessive jumping in young animals. Provide comfortable resting environments. Consider joint supplements (such as glucosamine, chondroitin) from a young age.

Treatment: Treatment includes weight management, moderate exercise, non-steroidal anti-inflammatory drugs, joint supplements, physical therapy, and acupuncture. Severe cases may require surgery. Providing non-slip mats and low beds helps reduce strain during daily activities.

The Importance of Regular Health Check-ups

Prevention is better than cure. Regular veterinary check-ups can help detect common diseases early. Recommended check-up frequency:

• Young age (under 1 year): Every 3-4 months to complete vaccination schedule
• Adult (1-7 years): At least once annually
• Middle-aged (7+ years): Every 6 months, including blood and urine tests
• Senior (12+ years): Every 6 months with detailed examinations, closely monitoring organ function

When Should You Take Your Pet to the Vet?

The following are warning signs requiring veterinary attention:

• Emergency (Seek immediate care): Difficulty breathing, inability to urinate for more than 12 hours, persistent severe vomiting, suspected poisoning, seizures, traumatic injury, acute abdominal bloating, heavy bleeding
• Urgent (See vet soon): Not eating for more than 24 hours, persistent vomiting or diarrhea, blood in urine or stool, significant weight loss, persistent fever, extreme lethargy, severe limping
• Schedule an appointment: Changes in appetite or drinking habits, changes in elimination habits, poor coat condition, mild limping, bad breath, behavior changes

Vaccination Recommendations

Regular vaccination is the most effective way to protect pets from infectious diseases:

Dog Vaccines

• Core vaccines (DHPP): Protects against distemper, infectious hepatitis, parvovirus, and parainfluenza
• Rabies vaccine: Required by Hong Kong law
• Leptospirosis vaccine: Recommended annually
• Kennel cough vaccine: Recommended for dogs that frequently visit dog parks or require boarding

Cat Vaccines

• FVRCP vaccine: Protects against feline panleukopenia, rhinotracheitis, and calicivirus
• FeLV vaccine: Recommended for cats that go outdoors or have contact with other cats
• Rabies vaccine: Recommended for outdoor cats

Petcore Veterinary Clinic provides comprehensive pet health check-up and vaccination services. Our professional veterinary team is dedicated to preventing and treating various common diseases, safeguarding your pet's health. If your pet shows any abnormal symptoms, please call to schedule a consultation.