Brazilian football icon Ronaldo said on Wednesday on his Twitter account that he has contracted dengue fever.
"I am convalescing. I was discharged last night. Now I have to rest to recover quickly," wrote the 34-year-old star, who last year accepted an invitation to become head of the 2014 World Cup organising committee. Brazil is to host the event.
"Damned mosquito," said the highest goal scorer in World Cup history, referring to the insect which transmits the dengue virus that causes the infectious disease.
Symptoms are fever, headache and joint pains.
Ronaldo, whose full name is Ronaldo Nazario de Lima, spent the year-end holidays in his house in the northeastern state of Bahia.
During his illustrious career he played for PSV Eindhoven, Barcelona, Real Madrid, Inter Milan and AC Milan in Europe and Cruzeiro and Corinthians in Brazil.