Knowing the signs of the most common diseases can save your dog's life. Not because you'll diagnose at home, but because you'll know when the situation is urgent and when you can wait a bit.
This article doesn't replace a veterinarian. It's a guide for you to understand what might be happening and act at the right time. When in doubt, always seek a professional.
Parvovirus: the most feared
Parvovirus is an extremely resistant and deadly virus, especially for puppies. Without treatment, the mortality rate exceeds 90%. With intensive treatment, many dogs survive, but the bill isn't cheap.
The virus attacks cells in the intestine and immune system. The dog literally cannot absorb water and nutrients, and becomes vulnerable to secondary infections.
What makes parvo so dangerous is speed. A puppy can be fine in the morning and in critical condition at night. If you notice these symptoms, especially in an unvaccinated puppy or with incomplete vaccination, run to the veterinarian. Every hour counts.
Prevention is simple: vaccine. The complete V10 protocol protects well. Until completing the three doses, avoid exposing the puppy to places with circulation of other dogs.
Distemper: permanent sequelae
Another serious viral disease, but that acts differently from parvo. Distemper affects multiple systems: respiratory, digestive and nervous. A dog can recover from the acute phase but be left with neurological sequelae for the rest of its life.
Many owners confuse the initial phase with a cold. And indeed, some dogs have only mild symptoms and recover. The problem is when the disease progresses.
If the virus reaches the nervous system, even the dog that survives can be left with permanent tics, known as "distemper sequelae". They are involuntary repetitive movements, usually in the head or limbs.
There's no specific treatment against the virus. The veterinarian treats symptoms and opportunistic infections while the dog's immune system fights the disease. The vaccine, again, is the best protection.
Worms: more common than it seems
Every dog will have worms at some point in life. Puppies are often already born infected because some worms pass from the mother to the puppy still in the uterus or through milk. The problem is when the infestation gets out of control.
There are several types of worms: roundworms (the most common), hookworms, whipworms and tapeworms. Each has its characteristics, but the general signs are similar.
In mild cases, the dog may not show any symptoms. You only discover it by doing a routine fecal exam. In moderate cases, a swollen belly starts to appear (especially in puppies), dull coat, weight loss even eating well, and sometimes diarrhea.
In severe infestations, you may see worms in feces or vomit. Some look like spaghetti (roundworms), others look like rice grains (tapeworm segments). In these cases, the dog can become anemic, very weak, and puppies can die.
Skin problems
Itching, hair loss, wounds... dermatological problems are one of the most frequent causes of veterinary consultation. And also one of the most frustrating, because it's not always easy to discover the cause.
Allergic dermatitis
Can be flea allergy (the most common), food allergy or environmental allergy (pollen, mites). The dog scratches a lot, bites its paws, rubs its snout, and the skin becomes red and irritated. Secondary infections by bacteria or fungi are frequent.
Identifying the allergen is difficult. Sometimes requires elimination diet (weeks eating only one new protein) or specific tests. Treatment may involve medications, medicated baths and, in some cases, immunotherapy.
Mange
There are two main types: sarcoptic mange (very contagious, causes intense itching) and demodectic mange (less contagious, more related to low immunity).
Sarcoptic is an itching emergency. The dog doesn't stop scratching, loses hair, the skin becomes thick and dark. Can pass to other animals and even to humans temporarily.
Demodectic appears more in puppies and dogs with compromised immune systems. Causes hair loss, usually starting on the face, without so much itching at first.
Both have treatment, but need veterinary diagnosis (skin scraping) to confirm and choose the right medication.
Otitis: inflamed ear
If your dog is shaking its head, scratching its ears, and there's a strong smell coming from inside, it's probably otitis. Some breeds are more prone: those with floppy and hairy ears, like Cocker and Basset, and those that swim a lot, like Labradors.
Otitis can be caused by bacteria, fungi, mites or allergies. Without treatment, it can become chronic and cause pain, hearing loss and even balance problems if the infection reaches the inner ear.
Cleaning ears regularly with appropriate product helps in prevention. But when otitis is already established, just cleaning doesn't help. Needs specific medication prescribed by the veterinarian.
Gastrointestinal problems
Occasional vomiting and diarrhea are part of canine life. Dog eats something it shouldn't, the stomach reacts, and that's it. The problem is when it doesn't pass or comes with other symptoms.
Vomiting once or twice, without other symptoms, in a dog that remains active and with appetite: observe. May have eaten something that didn't sit well. If it persists more than 24 hours or if the dog becomes apathetic, it's time to seek help.
Diarrhea is similar. Soft stools once is not an emergency. Persistent diarrhea, with blood, or in puppies, needs immediate attention because it dehydrates quickly.
A serious emergency is gastric torsion (or gastric dilatation volvulus). More common in large deep-chested breeds. The stomach twists on itself, cutting circulation. Signs are attempts to vomit without success, swollen and hard belly, extreme restlessness. It's a race against time: without emergency surgery, the dog dies in hours.
When to seek emergency
Some signs cannot wait until Monday or until the veterinarian opens:
Difficulty breathing, very rapid breathing or with strange noise. Choking, suffocation.
Bleeding that doesn't stop, whether from injury or coming from mouth/nose/anus/urine.
Inability to urinate, especially in males. May indicate urinary obstruction.
Seizures, especially if it's the first time or if they last more than 2-3 minutes.
Suspicion of poisoning or ingestion of foreign object.
Swollen and hard belly, with unsuccessful attempts to vomit.
Trauma: hit by car, fall from height, fight with another animal with serious injuries.
Extreme temperatures: hypothermia or hyperthermia (dog that got trapped in car, for example).
Prevention is still the best medicine
Up-to-date vaccines, regular deworming, quality feeding, adequate exercise and annual check-ups prevent most problems. A healthy dog is a dog that goes to the veterinarian when it's not sick.
Observe your dog. You know it better than anyone. When something seems different, trust your instinct. It's better to go to the veterinarian and find out it was nothing than to wait too long and complicate treatment.