Understand the symptoms and how to protect yourself with a vaccine for this sometimes deadly mosquito-borne disease.
Yellow fever is a viral infection spread by a particular type of mosquito. The infection is most common in areas of Africa and South America, affecting travelers to and residents of those areas.
In mild cases, yellow fever causes a fever, headache, nausea and vomiting. But yellow fever can become more serious, causing heart, liver and kidney problems along with bleeding. Up to 50% of people with the more-severe form of yellow fever die of the disease.
There's no specific treatment for yellow fever. But getting a yellow fever vaccine before traveling to an area in which the virus is known to exist can protect you from the disease.
During the first three to six days after you've developed yellow fever — the incubation period — you won't experience any signs or symptoms. After this, the infection enters an acute phase and then, in some cases, a toxic phase that can be life-threatening.
Once the infection enters the acute phase, you may experience signs and symptoms including:
These signs and symptoms usually improve and are gone within several days.
Although signs and symptoms may disappear for a day or two following the acute phase, some people with acute yellow fever then enter a toxic phase. During the toxic phase, acute signs and symptoms return and more-severe and life-threatening ones also appear. These can include:
The toxic phase of yellow fever can be fatal.
Yellow fever is caused by a virus that is spread by the Aedes aegypti mosquito. These mosquitoes thrive in and near human habitations where they breed in even the cleanest water. Most cases of yellow fever occur in sub-Saharan Africa and tropical South America.
Humans and monkeys are most commonly infected with the yellow fever virus. Mosquitoes transmit the virus back and forth between monkeys, humans or both.
When a mosquito bites a human or a monkey infected with yellow fever, the virus enters the mosquito's bloodstream and circulates before settling in the salivary glands. When the infected mosquito bites another monkey or human, the virus then enters the host's bloodstream, where it may cause illness.
You may be at risk of the disease if you travel to an area where mosquitoes continue to carry the yellow fever virus. These areas include sub-Saharan Africa and tropical South America.
Even if there aren't current reports of infected humans in these areas, it doesn't mean you're risk-free. It's possible that local populations have been vaccinated and are protected from the disease, or that cases of yellow fever just haven't been detected and officially reported.
If you're planning on traveling to these areas, you can protect yourself by getting a yellow fever vaccine at least several weeks before traveling.
Anyone can be infected with the yellow fever virus, but older adults are at greater risk of getting seriously ill.
Yellow fever results in death for 20% to 50% of those who develop severe disease. Complications during the toxic phase of a yellow fever infection include kidney and liver failure, jaundice, delirium, and coma.
People who survive the infection recover gradually over a period of several weeks to months, usually without significant organ damage. During this time a person may experience fatigue and jaundice. Other complications include secondary bacterial infections, such as pneumonia or blood infections.
A highly effective vaccine exists to prevent yellow fever. Yellow fever is known to be present in sub-Saharan Africa and parts of South America. If you live in one of these areas, talk to your doctor about whether you need the yellow fever vaccine. If you plan to travel in these areas, talk with your doctor at least 10 days, but preferably three to four weeks, before your trip begins. Some countries require travelers to present a valid certificate of immunization upon entry.
A single dose of the yellow fever vaccine provides protection for at least 10 years. Side effects are usually mild, lasting five to 10 days, and may include headaches, low-grade fevers, muscle pain, fatigue and soreness at the site of injection. More-significant reactions — such as developing a syndrome similar to actual yellow fever, inflammation of the brain or death — can occur, most often in infants and older adults. The vaccine is considered safest for those between the ages of 9 months and 60 years.
Talk to your doctor about whether the yellow fever vaccine is appropriate if your child is younger than 9 months, if you have a weakened immune system, are pregnant or if you're older than 60 years.
In addition to getting the vaccine, you can help protect yourself against yellow fever by protecting yourself against mosquitoes.
To reduce your exposure to mosquitoes:
To ward off mosquitoes with repellent, use both of the following:
Skin repellent. Products with the active ingredients DEET, IR3535 or picaridin provide long-lasting skin protection. Choose the concentration based on the hours of protection you need. In general, higher concentrations last longer.
Keep in mind that chemical repellents can be toxic, and use only the amount needed for the time you'll be outdoors. Don't use DEET on the hands of young children or on infants under 2 months of age. Instead, cover your infant's stroller or playpen with mosquito netting when outside.
According to the Centers for Disease Control and Prevention, oil of lemon eucalyptus, a more natural product, offers the same protection as DEET when used in similar concentrations. But these products should not be used on children younger than age 3.
Diagnosing yellow fever based on signs and symptoms can be difficult because early in its course, the infection can be easily confused with malaria, typhoid, dengue fever and other viral hemorrhagic fevers.
To diagnose your condition, your doctor will likely:
If you have yellow fever, your blood may reveal the virus itself. If not, blood tests also can detect antibodies and other substances specific to the virus.
No antiviral medications have proved helpful in treating yellow fever. As a result, treatment consists primarily of supportive care in a hospital. This includes providing fluids and oxygen, maintaining adequate blood pressure, replacing blood loss, providing dialysis for kidney failure, and treating any other infections that develop. Some people receive transfusions of plasma to replace blood proteins that improve clotting.
If you have yellow fever, your doctor will likely recommend that you stay inside, away from mosquitoes, to avoid transmitting the disease to others. Once you've had yellow fever, you'll be immune to the disease for the rest of your life.
Call your doctor if you've recently returned from travel abroad and develop mild symptoms similar to those that occur with yellow fever. If your symptoms are severe, go to an emergency room or call 911 or your local emergency number.
Here's some information to help you get ready, and know what to expect from your doctor.
The list below suggests questions to raise with your doctor about yellow fever. Don't hesitate to ask more questions during your appointment.
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to talk about in-depth. Your doctor may ask:
December 24th, 2020