Canine distemper is caused by a highly contagious virus that is spread through the coughs, urine and feces of infected animals. Puppies are the most susceptible.

Early symptoms such as fever and coughing often progress to vomiting and diarrhea and then to seizures, tremours and other neurologically related problems. Distemper is often fatal, and even recovered animals frequently experience lifelong difficulties.

Read more details about the disease.

Canine parvovirus is a hardy, highly contagious and often deadly virus that's spread through the feces of infected dogs. Carriers of the virus often display no symptoms.

Parvovirus usually attacks the intestinal tract causing symptoms such as bloody diarrhea and vomiting. Puppies are most vulnerable to the virus, and certain breeds including rottweilers and Labrador retrievers may show a higher susceptibility.

Canine adenovirus type 1 (infectious canine hepatitis) is transmitted through contact with the feces and body fluids of infected dogs.

This disease progresses very quickly with a variety of symptoms including fever, coughing and bloody diarrhea. It often leads to liver damage and chronic problems in surviving animals.

Parainfluenza affects puppies and older dogs most severely. Spread through nasal secretions, the virus causes a range of symptoms such as fever and coughing and can progress to potentially fatal conditions such as pneumonia.

Feline rhinotracheitis virus (feline herpes virus) mainly affects the upper respiratory tract and causes a variety of symptoms including sneezing, nasal discharge and conjunctivitis. Appetite loss is the most dangerous effect.

Transmission is through direct contact with the mouth, nose or eye discharge of infected cats, many of which show no symptoms. Once infected, a cat can become a carrier of the virus — often resulting in periodic flare-ups of symptoms.

Feline calicivirus is an extremely contagious viral disease that commonly affects the upper respiratory system, eyes and mouth but can involve the gastrointestinal and musculoskeletal systems.

Symptoms usually include fever, runny nose and oral lesions. Lameness and intestinal problems may also develop. Resistant to many disinfectants, the virus spreads through contact with the eye, nasal or mouth discharges of infected or carrier animals.

Feline panleukopenia is especially deadly for kittens. Symptoms include vomiting, high fever and weight loss.

The virus is easily transmitted, most commonly through direct or indirect contact with infected feces or urine. The virus can also be passed to  kittens in utero.

Rabies is a disease affecting mammals that is caused by the rabies virus. Rabies poses a particularly serious threat to public health because it is zoonotic (can be transferred between humans and animals).

The virus is usually spread by a bite or scratch from an infected animal. It ultimately infects the brain causing death.

For more details about rabies, please read "Rabies: what you need to know."