What Is Yellow Fever? Symptoms, Vaccines for Mosquito-borne Disease

Updated | Mosquitoes are more than pesky insects that cause itchy bites—they can also carry dangerous and deadly infections.

The same type of mosquito that carries the Zika virus that caused concern after an outbreak in Brazil from 2015 to 2016 also carries the yellow fever virus. Zika causes mild or no symptoms for most people, but it can cause major in-utero birth defects when a mother is infected with the virus, according to the Centers for Disease Control (CDC).

Yellow fever is more dangerous. In March, a travel notice was issued for people traveling to Brazil: “There is a large, ongoing outbreak of yellow fever in multiple states,” according to the CDC. The travel notice ranked Brazil at level 2, meaning travelers should take “enhanced precautions” due to a higher than desirable risk of contracting the virus.

Officials in South Florida are hoping the work they've done to prevent Zika will also help prevent yellow fever, the Sun-Sentinel reported.

“There have been no travel-associated cases of yellow fever identified in Florida in recent years. However, yellow fever virus and some other mosquito-borne disease activity has increased in parts of South and Central America recently,” Devin Galetta, interim communications director for the Florida Department of Health, told Newsweek.

“It is important for those traveling to areas where these diseases are present to use the mosquito bite precautions,” Galetta said. Such precautions could help keep travelers healthy, and could help keep the virus from making its way to Florida.

What is yellow fever?

Yellow fever is a virus that’s transmitted through an infected mosquito, according to the Florida Department of Health. Some people develop no symptoms at all, and those who do sometimes mistake them for a cold or the flu. Symptoms include body aches, fever, nausea, vomiting, fatigue and headaches, according to the World Health Organization.

For those who do have symptoms, the virus can lead to a high fever, jaundice, bleeding and even death, according to the CDC. Jaundice associated with the virus is what led to the name "yellow" fever.

How to prevent yellow fever

The most effective way to prevent yellow fever, especially for those traveling to areas where the virus is prevalent, is vaccination. A vaccine should be administered at least 10 days before traveling to a risk area; in certain countries it may be required for entry. The vaccine lasts a lifetime, but a booster is sometimes recommended, according to the CDC.

For those who aren’t vaccinated, covering skin, wearing insect repellent, spending time indoors or in screened-in areas and using a mosquito net while sleeping can all help prevent mosquito bites.

Where is yellow fever usually found?

The virus is primarily found in the tropics and subtropics in parts of Africa and South America, according to the CDC. The disease is rare in the United States, and the few cases are sometimes caused by travelers coming from an area where the virus is more prevalent.

This story was updated to include information from the Florida Department of Health.

mosquito A mosquito on a man in Yangon, Myanmar, on October 30, 2016. Myanmar's government said a pregnant foreign woman had been diagnosed with the country's first case of Zika, a mosquito-borne virus linked to birth defects. The same type of mosquito that carries Zika also carries yellow fever. Ye Aung Thu/Getty Images

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