Yellow fever in Brazil

The World Health Organization (WHO) declared an outbreak of yellow fever in southeastern Brazil in January. From July 1, 2017, through Jan. 14, 2018, there were 35 confirmed cases, resulting in 20 deaths, with an additional 145 suspected cases. The worst-hit area was São Paulo, which had 20 confirmed cases and 11 deaths.

Yellow fever is caused by a virus that is spread by mosquitoes. Symptoms include fever, headache, nausea and muscle pain. About 15% of infections progress to a more toxic phase with high fever, jaundice and internal bleeding. About half of those who experience the second phase die from the infection.

WHO and the Centers for Disease Control recommend getting a yellow fever vaccine at least 10 days before traveling to Brazil.