PORT ST. LUCIE, Fla. -- While doctors believe Ike Davis has contracted valley fever, the New York Mets first baseman says he is not suffering any symptoms of the disease.

"I feel great," Davis said Sunday morning. "And I don't have any symptoms of it. I'm not coughing. I'm not throwing up blood. I'm not doing anything. It's not even hard to breathe. The doctor said I could play -- and just don't get really, really fatigued. So that's what we're doing. And if I get really tired, I kind of just step to the side and take a break."

Doctors decided to send Davis to New York for additional tests after reviewing an X-ray of his lungs during a routine camp physical. However, Davis says that subsequent blood work didn't positively identify the disease.

Doctors told Davis his blood tests did not positively identify valley fever because he has either unknowingly had the disease for a while and it mostly has worked itself out of his system, or because the disease has yet to fully manifest itself.

Asked how long it may be in his system before running its course, Davis said: "It's person by person. A year, maybe. But another thing is, if you look at it, like 40 percent of people that live in Arizona get it in their life. It doesn't affect a lot of people that get it. So hopefully I'm one of those guys."

Davis, who spends his offseasons in Phoenix, suspects he may have contracted the disease while rehabbing a season-ending left-ankle injury in his native Arizona last summer.

Valley fever is a fungal infection found in desert regions of the Southwest. The fungus is released from the soil and inhaled.

"There were some dust storms during the summer when I was back in Arizona," said Davis, whose 2011 season ended with a collision with David Wright at Colorado on May 10. "I guess a lot of people have had complications from that."

Former Diamondbacks outfielder Conor Jackson suffered from a severe case of valley fever in 2009 while with Arizona and lost nearly a full year to the disease. Jackson described the symptoms at the time to the Arizona Republic as "mono on steroids."