PARIS - Cyclists knew her as “the carrier pigeon” — a nurse in the doping underworld who came to their hotels to deliver synthetic testosterone, EPO and other performance-enhancing drugs.

Such sordid accounts — provided by rider-turned-whistleblower Jesus Manzano — are all too believable these days. With the Tour de France set to begin July 7 in London, cycling arguably is in the worst shape it has ever been.

Ever since the 104-year-old Tour’s early days, doping has been as interlocked with cycling as shoe clips on bike pedals. Riders, mechanics, doctors and managers mostly honored a mafia-like code of silence. Until now.

The May 25 admission by 1996 Tour winner Bjarne Riis that he doped was a bombshell that, coming on top of another year of scandals, confessions, investigations and other doping cases, has brought cycling to its knees. Questions are mounting about whether the Tour and the sport can recover.

The 2006 Tour winner, Floyd Landis, will not defend his title this year because he’s fighting doping charges. Other top names — including Italian rider Ivan Basso — will be missing because they have been implicated in a massive doping scandal in Spain.

All Tour winners since at least 1996 have been tarred by admissions or accusations of doping.

Jan Ullrich, the 1997 victor, is under investigation. The late Marco Pantani failed a random blood test a year after his 1998 victory. Seven-time winner Lance Armstrong spent much of his career fighting suspicions that he doped. Riis was the first from the EPO-fueled 1990s to admit that he cheated and say he no longer considers himself a worthy winner.

“It’s unfortunate that all these things have come together at the same time,” International Cycling Union president Pat McQuaid told The Associated Press in a telephone interview. “It’s going to take a couple of years to get the credibility back.”

Slide show 2006 Tour de France Landis finishes first in race that had heroics, crashes and a drug scandal that rocked the race even before it began.

Germany’s two public television networks have said they will not renew their contracts to broadcast the Tour without assurances it will be doping-free. The contracts are valid through next year.

But fans might not care. The recent Giro d’Italia drew 300,000 more television viewers per day this year than last, according to Tour de France director Christian Prudhomme. And while German sponsor MAN has ended its support for Riis’ Team CSC, team spokesman Brian Nygaard said possible successors have been lining up to replace it.

Ever since the 1998 Festina affair, which nearly derailed the Tour when French authorities found a stash of performance-enhancing drugs in a team car, cycling officials have billed each new doping revelation as a sign the sport finally was cleaning up.