Rory McIlroy's viral illness is a common problem among travelling golfers and the World No. 2 should make a complete recovery as long as he takes some rest, the European Tour's chief medical officer has said.
The 22-year-old has had a punishing playing schedule in Asia recently and his management team said at the Dubai World Championship on Friday that he was "exhausted" and "run down."
"This isn't an unusual situation in my experience on the tour," medical officer Roger Hawkes said on Saturday. "I've seen several players down the years with this sort of problem.
"I think it's probably the effects of a virus. The symptoms are maybe of fatigue. They feel like doing something one day, they do it, and then they don't have much energy the next day and it takes a period of time to get over that.
"The virus usually goes but what's left is a fatigue syndrome. If the low white blood count is low and the platelets are low, as they are in Rory's case, that indicates there is probably a virus in the system but nothing more than that.
"The remedy is to try and reduce the amount of total activity and then gradually build it up again over a period of time. The main thing though is the outlook is very good and most people recover," Hawkes added.
McIlroy looked tired and forlorn after closing his second-round 71 with two successive bogeys on Friday.
The Northern Irishman, who is five strokes adrift of leader Alvaro Quiros of Spain, said he was still unsure of the precise nature of his viral infection even though he had been under the weather for a couple of weeks.
McIlroy shrugged off his illness to win the Hong Kong Open last Sunday and at this week's season-ending event in Dubai he is locked in a straight fight with world number one Luke Donald to determine who finishes the season as Europe's top golfer.
Hawkes gave an insight into the ramifications of a low platelet count.
"Platelets are the agent that helps you clot so that when you get cut you stop bleeding," he explained.
"But for people with a virus the total count goes down a bit. They are also a window into the immune system.
"In a hot environment you try to normalise everyday conditions, make sure the sufferer is not too hot, not too cold, doesn't get dehydrated and also try to reduce the stress on the body."
McIlroy is due to play in next week's inaugural Thailand Golf Championship in Bangkok, the last event in the Asian Tour season, but said he would make a decision on whether to compete there after consulting his doctor on Saturday evening.