Urinary tract infections are caused when the bacteria get into the urine and travel up to the bladder. When it affects the lower urinary tract it is known as a bladder infection and when it affects the upper urinary tract it is known as a kidney infection. Symptoms include light fevers, pain in the lower abdomen, feels like urinating more often. Kidney infections may also often cause nausea and vomiting. E. coli bacteria cause the majority of UTIs, but many other bacteria, fungi, and parasites may also cause UTIs.