The Centers for Disease Control and Prevention (CDC) recommends those traveling to Brazil get a yellow fever vaccine at least 10 days before travel. "Currently, there are concerns regarding quite a large outbreak in Brazil that has been linked to yellow fever," says Dr. Nipunie Rajapakse, a pediatric infectious diseases specialist at Mayo Clinic. Yellow fever is a viral infection that is spread by mosquitoes.

Dr. Rajapakse says, “It’s called yellow fever because some stages of the illness can affect the liver. When your liver is damaged, you can have buildup of something called bilirubin that causes jaundice or a yellow discoloration to the skin and the eyes.”

Most people who are infected will not have any symptoms or will develop a fever or flu-like illness. It can take 3 – 6 days for symptoms to develop once a person is infected. Approximately 15 percent of people who get infected progress to develop a severe form of illness in which fever, jaundice, bleeding, shock and organ failure can occur.

“There is no treatment for yellow fever," says Dr. Rajapakse. "Most of the care is what we call supportive management. That means bringing people into hospital if they’re quite unwell and supporting their other bodily functions through the illness until they recover on their own. And, so, there’s no specific treatment that we can provide.”

Dr. Rajapakse says prevention through vaccinations is effective. Currently, health officials in Brazil are conducting mass vaccinations campaigns to try to prevent illness in as many people as possible. Travelers also should protect themselves from mosquito bites by using an insect repellent registered with the U.S. Environmental Protection Agency, wearing long sleeves and long pants when outdoors, and staying in accommodations with screened or air-conditioned rooms.

The CDC says travelers who have not been vaccinated should avoid traveling to areas of Brazil where there are outbreaks. Areas with outbreaks include the states of Rio de Janeiro, Minas Gerais and São Paulo.