Tyson Beckford -- Terminal Case of BIEBERITIS

Tyson Beckford IS TERRIBLY ILL ... succumbing to a powerful strain of the Justin Bieber virus that's been wreaking havoc on the nation.

Beckford was photographed out in NYC Tuesday, showing the telltale symptom of the gruesome disease ... a shirtless, hairless torso.

Beckford kept a smile on his face despite his condition, but if Bieber's any indication, the prognosis isn't good. It's not good at all.

Tyson Beckford ... we hardly knew ye.