Maddie with her mother Kerryn. "I don't think its quite real yet and I don't know when it will be real. For us, it's like we expect her to walk out of her bedroom any minute," her mother Kerryn Tippett says. The three-year-old started to fall ill with a minor sniffle last Sunday. By Monday morning, she was achy and listless. Mrs Tippett took Maddie to the doctor who asked to see her again the next day. Her condition worsened in the early hours of Tuesday morning so her parents took her to the John Hunter Hospital in Newcastle.

YouTube sensation: Maddie. Credit:Screen grab She was sedated and incubated in ICU. Blood tests showed respiratory syncytial virus (RSV) and adenovirus, common in children. One of the viruses is reported to have had given Maddie a slight case of pneumonia. Later that afternoon she went into cardiac arrest. Doctors worked on Maddie's heart for 40 minutes. One of the viruses had caused her heart to fail. Intensive care specialist at John Hunter Hospital, Martin Rowley, said Maddie had cardiomyopathy and myocarditis, which cause inflammation of the heart. "These severe complications are rare but may be life-threatening. A combination of the two viruses in vulnerable patients is of concern," said Dr Rowley.

Mrs Tippett said she had a lot of love and support, "which we are just so grateful for and we are grateful for everything the hospital did and for people who just write a message to say they are thinking of us". "We have a lot of love and support around us, which we are just so grateful for and we are grateful for everything the hospital did and for people who just write a message to say they are thinking of us," Kerryn says. "She will be remembered for who she was, which was this beautiful little girl who could make people smile." The video that made so many people smile was originally shot for her maternal grandparents about the time of her first birthday. Her father posted it online and it caught the attention of people around the world. The family were invited to appear on television shows to talk about their daughter. "We will have times where we can go to that video for comfort but I think, as we are now, part of us is thinking about the stuff we won't get to share with her and that's devastating," Mrs Tippett said.

Such was Maddie's charm, last August her father made a follow-up video to Who's Your Favourite, this time starring Scrubs actor Zach Braff. It's called Listen to your Uncle Zach. In it, Braff instructs Maddie to chose her father as her favourite parent. "There wasn't a single person she couldn't bring a smile to their face," Mrs Tippett said. "Follow your instinct. If your child has a sniffle and you are concerned, go to the doctor - the support is there. Us taking Maddie to the hospital was the best possible thing because she was always going to get worse and if she had got worse at home we would not have been able to deal with that." Correction: The original version of this story said that Maddie died from cold viruses.