Hi Dr. Barchas,
Drinking contaminated water does not cause bacterial urinary tract infections (also known as bladder infections). When cats or dogs drink water, the water passes first into the stomach. From there, it is absorbed into the bloodstream. Ultimately, it enters the kidneys and is excreted into the bladder. Pets’ bodies have powerful mechanisms that help prevent bacteria, which cause infections, from getting into the bloodstream. Therefore, they aren’t likely to make it to the bladder.
Instead, most bladder infections originate at the other end of the system. In other words, the source of Tigger’s bladder infection was probably contamination at her hind end. That is the most common cause of bladder infections.
Less often, there are other factors that may contribute to bladder infections. Dehydration, diabetes, obesity, kidney failure, incontinence, or a weakened immune system make them more likely. However, drinking dirty water, in and of itself, does not cause basic urinary tract infections.
That said, contaminated water can cause a host of other problems. Since water goes to the stomach first, most problems associated with dirty water manifest as gastrointestinal problems. Drinking contaminated water can cause diarrhea, loss of appetite, nausea, and vomiting. Parasites, such as Giardia, may reside in mud puddles. I would recommend that you keep Tigger away from muddy areas.