DUBAI, December 9, 2011 (AFP) - Rory McIlroy admitted on Friday that a crippling bout of dengue fever, which has affected his pursuit of the European number one spot, could rule him out of the season-ending Asian event in Thailand next week.
The Northern Irishman, involved in a thrilling battle with England's Luke Donald for the top ranking in Dubai, has suffered exhaustion and a skewed blood count as a result of the illness which is caused by a mosquito bite.
"It could have been a number of things and I'm going to see a doctor again tomorrow before deciding whether to go to Thailand next week," said US Open champion McIlroy.
"To be honest, I'm ready for the season to be done and looking forward to putting the clubs away."
McIlroy needs to win the $7.5 million Dubai World Championship to dethrone Donald from the number one spot, but ended Friday's second round five shots behind leader Alvaro Quiros of Spain.
Donald, who could become the only player to win the Money List both on the US PGA Tour and the European Tour on Sunday, closed with three consecutive birdies in a round of four-under par 68, which elevated him to tied 12th place.
The Englishman needs to finish in the top nine to win the Race to Dubai.