A specific underlying cause has not yet been determined for the lower urinary tract diseases (LUTD) that affect an estimated quarter to half a million cats annually. Microscopic evidence suggests feline calicivirus may play a causative role. Recently a calicivirus from the urine of a cat with cystitis was isolated. It is unknown whether this urine calicivirus causes idiopathic cystitis or merely represents coincidental shedding of a wild type or vaccine strain of calicivirus. This study will help determine whether it is a causative agent of cystitis. The first goal is to sequence the portion of the virus’ genetic code so it can be compared to the code of other strains. If the urine virus isolate is unique and if subsequent studies can show a cause and effect relationship for idiopathic cystitis, the second goal will be to develop specific treatments and/or more appropriate vaccines. Information gained from this study may lead to better treatment options and improved outcomes for cats with LUTD.