A bladder infection, also called cystitis, is a type of urinary tract infection. The infection is usually caused by bacteria, although it can also be caused by a virus.
Females are more prone to bladder infections than males because the urethra in females is short.
The short urethra makes it easier for bacteria to travel up the urethra and into the bladder from the anus or vagina during normal activities such as wiping or sexual intercourse. Bladder infections frequently occur in young women who have just become sexually active. This is sometimes called honeymoon cystitis. If the flow of urine is blocked or the bladder cannot empty completely, there is an increased likelihood of a bladder infection. For example, a stone or tumor might block the flow of urine.