Published: Dec 09, 2011 3:13 PM EST
Updated: Dec 10, 2011 7:30 AM EST

DUBAI, United Arab Emirates (AP) - The fatigue that Rory McIlroy has felt for the past several weeks was most likely the lingering effects of dengue fever, he said Friday.

The 22-year-old McIlroy said his illness had not been a factor as he struggled down the stretch in the second round of the Dubai World Championship. He had two late bogeys Friday to finish with a 1-under 71 and 7 under for the tournament.

No. 2-ranked McIlroy is five shots behind Alvaro Quiros of Spain and must win to have any chance of claiming the European money title ahead of Luke Donald.

McIlroy said he got blood test results back on Thursday which showed that his white blood cell count remained low. He said all he can do is "keep hydrated" to help offset the fatigue, which also plagued him at the Hong Kong Open where he struggled in the second and third round before coming from behind on Sunday to win.

The U.S. Open champion believes he picked up a "mild case of dengue fever" when he was playing tournaments in South Korea or China at the end of October and early November. But he didn't rule out that it could also have been a case of food poisoning, though he said he didn't have it anymore and was just suffering the "the lasting effects which my body is trying to fight to obviously get back to 100 percent."

"To be honest, I don't feel too bad," he said after his round. "But yeah, we got the blood test results back last night and yeah, I mean, it was basically the same. Platelet count was low and my blood cell count was low as well."

McIlroy said he would see a doctor Saturday before determining if he will pull out of the Thailand Golf Championship that starts next week.

"She's going to have a look at me and determine whether this is the last tournament for me or not or if I go to Thailand next week," he said. "To be honest, I'm ready for the season to be done ... I'm looking forward to putting the clubs away at whatever point that is and taking a break."

McIlroy said the only way for him to fully recover was get plenty of rest, cut down on the travel and "let my body just get back to full health as quickly as possible."