Infectious disease experts are concerned about a potential reemergence of yellow fever in the U.S. Do I need to worry?

When you think of yellow fever and other mosquito-borne illnesses, which are diseases that spread to people when they’re bitten by an infected mosquito, you probably assume they don’t happen often in the U.S. — and you would be right.

While these diseases are more common in other places of the world, particularly Africa and South America, they are starting to rise in the U.S. In June, for example, malaria was detected in the U.S. for the first time in 20 years. More recently, the first locally acquired case of dengue virus was detected in California.

Experts are now concerned that yellow fever — which hasn’t had a major outbreak in the U.S. since 1905, when it killed 900 people in New Orleans — could make a comeback as well.

What’s happening

Baylor College of Medicine recently issued a release stating that cases of mosquito-transmitted virus infections are increasing, especially in the Southern states — which could cause a reemergence of yellow fever.

Infectious disease experts at both Baylor and Stanford School of Medicine published a piece in the New England Journal of Medicine warning about yellow fever and urging that it be prioritized in national pandemic preparedness planning.

Experts say that climate change is playing a role in the uptick of these mosquito-borne diseases in the U.S. “The threat of yellow fever developing in America is closely linked to rising temperatures and climate change,” Dr. Sarah Park, medical director at Karius, tells Yahoo Life. “Mosquitos love warm, wet weather.”

Do I need to worry?

As with many diseases, the seriousness of yellow fever depends on the individual case. However, there’s less need to worry now than there was during the last U.S. outbreak more than a hundred years ago.

Yellow fever can be deadly, but most people have no symptoms or mild symptoms and completely recover, according to the Centers for Disease Control and Prevention. “The mortality rate in modern times is low, thanks to modern medicine and a vaccine that reduces the risk of serious disease,” Dr. Linda Yancey, infectious disease specialist at Memorial Hermann Health System in Houston, tells Yahoo Life.

The yellow fever vaccine, which has been available for 80 years, isn’t part of standard immunizations in the U.S. and is mainly administered when people are traveling to a place that has active cases, such as Africa or South America, explains Yancey.

That doesn’t necessarily mean the U.S. is or will be 100 percent safe, however. “We are seeing an uptick in several mosquito-borne diseases in the U.S., including malaria and dengue fever,” Yancey says. “If those can come back, then there is no reason that yellow fever could not come back as well.”

Outbreaks are historically most likely to hit the South, according to Park, along ports such as New Orleans; Galveston, Texas; and along the Mississippi River.

However, as Park points out, “The spread of mosquito-borne diseases in the U.S. is very limited because we all tend to sleep indoors with air conditioning and there are no native nonhuman primate populations,” meaning mosquitos have less opportunity to bite people or animals that can act as hosts.

What can I do about it?

First and foremost, get the vaccine, if you’re traveling to an area where there’s yellow fever. (The CDC has yellow fever maps that can help pinpoint the specifics, too.) “The yellow fever vaccine is safe and offers lifelong immunity against the disease,” Park says. “Currently, the vaccine is recommended for people who are age 9 months or older and traveling to or living in areas at risk for yellow fever virus in Africa and South America.” She adds that getting the vaccine may be a requirement to enter certain countries.

According to Yancey, your best bet otherwise is to avoid or fend off mosquitos whenever possible. If you’ll be outside in an area with mosquitos, she says, you can use repellents such as Deet, picaridin or permethrin, the latter of which is applied to clothing.

Treating clothes with permethrin is “a great strategy,” says Yancey, because it can last through several wash cycles, “and for little kids because they don’t tend to like the feel of repellents on their skin.”

Park also recommends wearing loose-fitting, long-sleeved shirts and pants; sleeping under a mosquito net if screened rooms aren’t available; staying in air-conditioned spaces when you can; and staying informed. “Before traveling, check the CDC or WHO websites for updates on yellow fever risk in the intended destination,” she says.

Knowing the symptoms of yellow fever also can’t hurt. The telltale sign is yellow eyes and skin, Yancey says, which is the result of the virus attacking the liver.

The signs may look different at first, however. Park says the initial symptoms include fever, chills, a severe headache, back pain, body aches, fatigue, nausea and vomiting.

“Most people improve after this initial phase,” she says. “However, roughly 15 percent of patients can enter a more toxic phase within 24 hours.” At that point, she says, you may notice a high fever, jaundice, bleeding, abdominal pain, shock and even organ dysfunction.

If you notice these signs, both Yancey and Park urge you to seek medical attention immediately. “Early detection and supportive care can make a significant difference in outcomes,” Park says, advising patients to let their doctor know if they’ve traveled (and to where) in the two weeks prior to the symptoms starting.

The main takeaway

Experts say awareness, protecting yourself from being bitten by mosquitoes and getting the vaccine if traveling to countries at risk of yellow fever virus is key.

“The disease is something that should be on the radar of public health so that we are ready to act if there is an outbreak, but it is going to be fairly easy to contain if there is,” Yancey says. “Yellow fever is very uncommon in the U.S., but there are other vaccine-preventable viruses that are.”