The first symptoms are obvious: the 150 or so love-smitten lasses who lined up last Friday around the block of MuchMusic, are declaring their devotion to pop music's latest cherub – Justin Bieber – through homemade "I Heart Justin" T-shirts, handheld posters and banners.
The number may seem small at first glance, but it's only 9:40 a.m. When the fresh-faced mop-top finally takes to the stage for his debut Much on Demand performance eight hours later, the sizeable armada flotilla of transfixed teenagers – numbering around 1,000 as they lay siege to the corner of Queen and John – unleash siren squeals of eardrum-shattering adoration.
"Marry me!" screams one decibel-smasher, managing to cut the air amidst a sea of unabashed love declarations, as Bieber slaps hands with the crowd and never loses his charismatic smile, walking through a gauntlet of outstretched hands straining to touch the latest Adonis.
"You fans are amazing!" shouts Bieber. The claim to fame of the 15-year-old – a protégé of R&B superstar Usher – rests on "One Time," a single upbeat pronouncement of puppy love that's still very much in the embryonic stages of becoming a U.S. hit.
To this shrieking wall of teeming estrogen, however, Justin Bieber has already penetrated the Jonas Brothers stratosphere of popularity. What's more, he's one of us: Canadian, hailing from nearby Stratford.
So how did Bieber Fever infect so many so quickly? Virally, of course: While there's no shortage of Disney (Miley Cyrus, the aforementioned Jonas trio, and Demi Lovato) and non-Disney (16-year-old Shiloh, another Canadian) teen talent flooding the market, none has exploited the YouTube, Twitter, MySpace and Facebook social networks quite as effectively as young Bieber.
YouTube has been his biggest coup: as of Friday, almost 3.8 million viewers have seen Bieber's official video at least "One Time." Ten million more have witnessed his performance of Chris Brown's "With You."
Even when Bieber simply plays the drums – one of four instrumental talents self-taught by ear that include guitar, piano and trumpet – spectators are attracted: almost 500,000 at last count.
Thrown in over 278,000 Facebook fans, 105,000 Twitter followers and 2.5 million MySpace fans, and Bieber is helping to Usher in a new era of music marketing: immediacy.
"I think Twitter has allowed the average fan to feel like they're hanging out with the artist," says Daniel Mekinda, whose Toronto firm tanjola manages the career of Universal recording artist Shiloh.
"It allows for a much quicker, simpler dialogue between the artist and their fans, and created a new, closer relationship between the artist and the fan."
It's certainly benefited Bieber, who regularly Twitters his whereabouts his promotional travels. The young singer, now based in Atlanta after signing a record deal eight months ago backed by label powerhouse Island Def Jam Records, handles such duties with aplomb.
"It's been awesome," he smiles, a little groggy during this early morning interview at a downtown hotel.
"At first, I didn't know if this is what I wanted. But I really love to be in the spotlight, and just be the centre of the attention."
In fact, a year ago, he claims his aspirations were much different. He attended Stratford's Northwestern Secondary, dated a few girls, and lived the life of a "regular kid.
"Before, I was really concentrating on sports," says Bieber, who lives with Pattie, his mother. "I played hockey a lot. I was really focused on sports."
However, three years ago, he entered the local contest Stratford Idol, and decided to bring a camera to record his performance for absent family members.
"I put videos of the competition on YouTube for them to see, and it just kind of blew up," Bieber recalls.
"I got a couple thousand hits, and then I got a couple million hits."
Bieber posted more videos of himself covering hits, but it was his version of Ne-Yo's "So Sick" that caught the attention of Scooter Braun, a former marketing executive with Jermaine Dupri's So So Def Records. Braun was engaged in some consulting work for Akon when he discovered Bieber.
"I was online doing research – and Akon's kid was singing Aretha Franklin's `Respect,'" Braun remembers. "There was a related video – and I clicked it, thinking it was the same person – and it was Justin in his first-ever singing competition at 12 years old."
Braun found more Bieber videos, including one of him busking in front of the Avon Theatre, but was sold by his Ne-Yo rendition.
"I was blown away that a little kid had a range like that," admits Braun, who also manages rapper Asher Roth. "Then I stalked him."
Braun left messages at school and with anyone he could think of to reach Bieber, who said his mother initially called his future manager back "to shut him up."
Instead, a two-and-a-half hour conversation ensued.
"It turned out he was a cool guy," say Bieber. "He flew me out to Atlanta where I went to a studio to meet some people, and Usher was there. It was an accident that we met. I went up to him and said, `Usher, Usher! I love your songs. You want me to sing you one?'
"And he politely denied me."
Usher eventually came around, flying the youth back to Atlanta for an audition, and then emerging victorious in a bidding war against Justin Timberlake to partner in Bieber's recording career with manager Braun.
"Usher is very passionate about this project," states Scooter Braun.
"He's very protective of Justin. He sees himself at that age, and he doesn't want Justin making any of the mistakes he made. He wants Justin to win.
"And one of the best things about having Usher as part of the team, is that he will understand what Justin is going through. To have that outlet for Justin is invaluable and really a blessing."
The odds seem to be stacked in Bieber's favour. "One Time," which has already been a Top-10 hit on iTunes Canada, is written by Chris "Tricky" Stewart and Terius "the-Dream" Nash, authors of Rihanna's mega-hit "Umbrella" and Beyoncé's chart-topping "Single Ladies (Put A Ring on It)"; his debut album My World will be dropping before the end of the year (a release date is still being mulled over) and he's appearing in an upcoming Nickelodeon movie called School Gyrls with Mr. Mariah Carey, Nick Cannon.
At the moment, however, Bieber is trying to retain as much normalcy as he can with a hectic promotion schedule that finds him in Florida, Michigan, Kentucky, New Jersey and New York before September.
"I sort of set out one day a week at least to myself, to just be a regular kid and do regular things," he says.
"I think it's really important, because I'll never get these years back. I'm working a lot now, and I'll never get these years back.
"I don't want to be 30 and say, `Wow, I didn't really do anything with my childhood,' so, I'm trying to do what I'm doing and trying to be a kid."