Chris Horner is fighting against a bacterium that affects his lungs and the condition could mean the end of his career. If he fails to return to full health, the winner of the 2013 Vuelta a Espana assumes that retirement is the only solution The 44-year-old veteran says that the condition has hampered him since the 2014 Tour de France.

Pseudomonas aeruginosa. This is the "superbug" that is affecting Horner who has revealed the details of his illness in a phone conversation with Business Insider and "seriously affects his lungs during competition." "It feels like asthma, but it's not asthma. The harder I race, the more I exert myself and the more it affects the lungs and causes the lungs to just collapse. It's the same effect as having an allergic reaction that asthma gives you," Horner says.

Horner, who competed in his home country with the continental Airgas-Safeway team in 2015, tires after a prolonged physical effort and therefore in a race, but it was not until recently that he found the reason. "I knew there was some kind of bug down there, and they finally found it at the end of October. I did eight rounds of antibiotics and just finished my ninth," he said. After bronchoscopy, "they know exactly what they're trying to kill."

Horner does not lose hope. "Every doctor I talk to says, 'You're on the right path — you just gotta wait it out.' So I'm trying to keep the head in a good place, but if the season starts and I got a bug in the lungs, maybe I move on to something else. We'll see if the latest round of antibiotics works its magic in the coming weeks. I'd love to see how long I could race my bike for," he said. "I mean, I'm 45 next year. In cycling, most riders are done at by 34, a few go 35, and 36 is old. So when you're going 44 like I was this year, that's eight years past the expiration date."

Horner is convinced that the bug entered his body at the 2014 Tour de France. "I'm thinking it was picked up on the cobblestone day [stage 5] when it rained and we were racing across the cobbles," he said. "But it's a guess. No one could tell you."

Nevertheless, he still hopes to return to the peloton. "If I can get healthy I'm gonna race my bike — if I can't, then I'm going to find something else to do. It's difficult, because it's not like a broken bone. If the doctors can fix it with antibiotics and the lungs go back to normal, and I have the same kind of legs I had this year at the Tour of Utah, then I'm going to race my bike and win a bunch of races. But if they can't, maybe I call it a career," he said.

Professional since 1995, Horner won the Vuelta ahead Vincenzo Nibali in 2013 at almost 42 years of age. He also won the Tour of California in 2011 and the Tour of the Basque Country in 2010 and was second in Tirreno-Adriatico in 2012. In the Tour de France, he was tenth in 2010, 13th in 2012 and 17th in 2014.

In his last year at the elite level with Lampre-Merida in 2014, he suffered a serious crash before the Giro - a punctured lung and four broken ribs were the consequences - but he was still 17th in the Tour de France and second in the Tour of Utah. The team didn't allow him to start the Vuelta due to low cortisol levels that forced him to take a break as per rules of the Movement for a Credible Cycling (MPCC).

His professional teams were La Française des Jeux (1998-1999), Mercury (2000-2001), Prime Alliance (2001-2002), Saturn (2003), Webcor (2004), Saunier Duval (2004-2005), Davitamon -Lotto (2006), Predictor Lotto (2007), Astana (2008-2009), RadioShack (2010-2013), Lampre-Merida (2014) and Airgas-Safeway (2015).