The World's Ugliest Dog 2018 has died at the age of nine, her owner has said.

​Zsa Zsa the English bulldog won the title of World's Ugliest Dog just two weeks ago in Petaluma, California.

Owner Megan Brainard of Anoka, Minnesota, said the dog died in her sleep early Tuesday morning.

"She's been staying over at my dad's house. He woke up this morning and found her passed away," Ms Brainard told Today.

The stout, long-tongued English bulldog won the annual competition, which started as a parody of more traditional pure-breed dog contests.

The death of Zsa Zsa, and the contest as a whole, points to a wider issue in dog breeding.

English bulldogs are one of the most inbred types of dogs, with some geneticists saying the problem is now so bad their health will never be able to improve.

World's Ugliest Dog 2018 Show all 11 1 /11 World's Ugliest Dog 2018 World's Ugliest Dog 2018 World's Ugliest Dog 2018 Zsa Zsa, an English Bulldog owned by Megan Brainard, stands onstage after being announced the winner of the World's Ugliest Dog Contest AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Megan Brainard reacts after her dog Zsa Zsa, bottom, is announced the winner of the World's Ugliest Dog Contest AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Zsa Zsa stands onstage after being announced the winner of the World's Ugliest Dog Contest AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Rascal Deux is held by owner Dane Andrew AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Wild Thang, a Pekingese, stands onstage AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Himisaboo, Chinese Crested and Dachshund mix, walks onstage AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Zsa Zsa, an English Bulldog, walks onstage AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Meatloaf, a bulldog mix, walks onstage AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Martha, a Neopolitan Mastiff who won the 2017 World's Ugliest Dog Contest, stands onstage before this year's winner was announced AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Zsa Zsa, an English Bulldog, stands onstage with Megan Brainard, before being announced the winner of the World's Ugliest Dog Contest AP World's Ugliest Dog 2018 World's Ugliest Dog 2018 Josie, a Chinese Crested mix, is checked by judges Debbie Abrams, right, and Jo Ling Kent AP

Due to their unique physique, they often suffer from a range of health problems and ailments.

Their heavily wrinkled faces are prone to skin infections, and their narrow nostrils mean they are more likely to have breathing difficulties.

Such traits are similar in other pedigrees, such as the incredibly popular breed pugs.

World's Ugliest Dog is not the first competition to draw attention to the problem of dog breeding.

Animal rights protesters stormed this year's final of one of the biggest dog contests in the world, Crufts.

The two intruders were wrestled to the ground by security as they tried to unfurl banners reading "canine eugenics" on live television.