Dengue fever is widespread in the state of São Paulo, Brazil
Of the 645 cities in the state, 604 (90 percent) have reported at least 1 case of dengue fever. Travellers to areas where the dengue fever virus is active can reduce their risk of exposure by taking all necessary precautions to avoid mosquito bites. Many persons with dengue fever do not seek medical care and are not reported to health authorities. There may be many more cases in the community than the reports indicate.