A common litter box in a multi-cat household is an ideal setting for the spread of disease from one cat to another.
Many viruses, some fatal (for example, the feline leukemia virus), are spread from cat to cat via saliva, urine and feces.
If a cat has roundworms or tapeworms, she can pass the eggs of these parasites in her feces. And then any animal coming into contact with the feces of that infected cat becomes at risk of contracting the worms.
(Yes, some parasites can even be passed from cats to people in this same manner, such as roundworms and the organism that causes toxoplasmosis.)
The quick answer, then, is: Yes, cats can get a bladder infection from an unclean litter box, but it’s rare. Cats are noted for their cleanliness. When they have to use a dirty litter box and then clean themselves, licking their paws, they risk getting an infection.
Urinary tract infection is, as the name implies, a bacterial infection that affects the urinary tract. Bladder infection, also known as cystitis, is the most common type of urinary tract infection (UTI). Common causes of UTIs in cats include diet, stress and age.
If your cat is not using the litter box or if she is spending a lot of time trying to use it, this could be a sign that she has an UTI. These infections, although rarely fatal, can be serious. They require evaluation and treatment from a veterinarian.
More on the Litter Box Link
I’m not implying that an unclean litter box is the cause of most urinary tract infections, but it certainly will not help prevent UTIs.
If your cat holds his urine in hopes of a fresh, clean box appearing later, he could be setting himself up for an infection. According to the Humane Society, noticing your cat’s litter box habits will be a huge help in catching a urinary tract infection early.
Cats shouldn’t have to dig around in the litter box to find a clean spot, according to Lisa A. Pierson, DVM. Clumps of urine and feces should be removed twice a day. Finding a litter that clumps well will make it easier to pinpoint when cleaning is needed.
The facts are in: Yes, it is possible, though uncommon, that cats can get bladder infections from a dirty litter box.
So, as your kitty does her best at keeping herself clean, do your part to help her out by making sure her litter box stays sanitary as well. Sure, it’s a dirty job — but not only will it look and smell better, but it will also help keep your pet happy and healthy.