Urinary Tract Infections (Bladder Infections) in Cats and Dogs

Urinary Tract Infections (Bladder Infections) in Cats and Dogs

Animals Affected

Cats and dogs of both genders.


Under normal circumstances, the urinary bladder is free of bacteria. Urinary tract infections occur when bacteria occupy (infect) the bladder. The most frequent source of bacteria in urinary tract infections is the animal’s own feces, but other sources are possible. Although some animals with urinary tract infections do not show symptoms, most cases are very painful. If not treated, bladder infections can spread to the kidneys, where they can cause very serious illness.


Symptoms of urinary tract infections include:

Animals may show any combination of these symptoms. Some animals with bladder infections show no symptoms.

Risk Factors

  • Females suffer a higher rate of infection than males, but either gender can be affected.
  • Animals with weakened immune systems are at greater risk. This includes elderly animals, animals with other illnesses such as cancer or dental disease, and cats infected with FIV or feline leukemia virus.
  • Cats and dogs with diabetes have much higher rates of bladder infections.
  • Obese cats and dogs are less able to groom the area around their genitals. Similarly, animals with long hair can accumulate feces near their genitals. Feces around the genitals predisposes animals to bladder infections.
  • Animals with bladder stones or masses in their bladder have higher rates of urinary tract infections.
  • Incontinent animals are more likely to suffer bladder infections.

A large number of animals that develop urinary tract infections will not fall into one of the categories listed above.


Untreated bladder infections can lead to chronic and severe pain, weight loss, and house soiling (in both cats and dogs). Bladder infections that spread to the kidneys can cause severe illness or death. Urinary tract infections can lead to bladder stones and crystals in the urine.


Urine testing is the mainstay of diagnosing bladder infections. In some cases, animals will be treated with antibiotics and monitored for a response.


Uncomplicated urinary tract infections can be cured with antibiotics. Animals with bladder infections may need to take antibiotics for two weeks or longer. In most cases, symptoms of bladder infections resolve within 48 hours of starting treatment.

Painkillers may help some animals. However, antibiotic administration almost always leads to rapid resolution of symptoms and is the most effective way to relieve the pain associated with urinary tract infections.


After treatment for a urinary tract infection, urine tests should be repeated to confirm that the infection has been completely eliminated.


Animals with bladder infections that do not show significant improvement within the first 48 hours of treatment should be reassessed by a veterinarian to investigate for other possible causes of the symptoms.

Recurrent or intractable urinary infections occur in some animals. These sorts of infections may require advanced and repeated urine testing, as well as diagnostic imaging such as X-rays or ultrasound exams.

In many cases, urine for testing is collected by inserting a needle into the bladder. This results in the most diagnostically useful sample. Although it sounds dangerous, this technique has a very low rate of complications.  Most animals show no signs of pain or distress during the procedure.

Home remedies, such as oral administration of cranberry juice, do not reliably treat bladder infections and should not be substituted for appropriate therapy with antibiotics.

By the time urinary tract infections are diagnosed in animals, they frequently are longstanding and severe. Because of this, animals generally must take antibiotics for much longer than people with bladder infections.

Copyright © Eric Barchas, DVM All rights reserved.
The contents of this page are provided for general informational purposes only. Under no circumstances should this page be substituted for professional consultation with a veterinarian.

Peeing in house