`` The one thing in our favor is that it is winter in Brazil , '' Sharp said . Brazil has reported the most cases of dengue fever in South America over the past 30 years . High-risk cities are Recife , Recife and U.S. , studies say . Many Natal dengue cases involve travel to a dengue-endemic country . Hepatitis A and B , yellow fever , typhoid and malaria are also concerns during World Cup .
Brazil has reported the most cases of dengue fever in South America over the past 30 years . High-risk cities are Recife , Recife and U.S. , studies say . Many Natal dengue cases involve travel to a dengue-endemic country . Hepatitis A and B , yellow fever , typhoid and malaria are also concerns during World Cup .