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Answering your most common questions about the yellow fever virus

Updated: Jul 24, 2023



What is yellow fever and how is it transmitted?

Yellow fever is a viral illness transmitted by the bite of an infected mosquito. It is found in certain parts of Africa and South America. The virus is transmitted by Aedes and Haemagogus genera of mosquito, which can also transmit other diseases such as dengue fever and Zika virus. Yellow fever has similar symptoms to malaria but is not treatable like malaria (with anti-malarials). The disease is spread from human to human by the mosquitos. Non-human primates can also carry the disease though they are often less affected by it.

What are the symptoms of yellow fever?

Yellow fever can cause severe illness, with symptoms including fever, headache, muscle pain, and nausea. In severe cases, it can lead to jaundice (a yellowing of the skin and whites of the eyes), abdominal pain, vomiting, and bleeding from the mouth, nose, eyes, or stomach. In some cases, yellow fever can be fatal.

How is yellow fever diagnosed?

Yellow fever is diagnosed based on a combination of clinical symptoms, laboratory testing, and epidemiological information. A healthcare provider will typically consider the patient's medical history, including their travel history and potential exposure to the virus, as well as their physical examination and laboratory test results, to make a diagnosis of yellow fever.


To confirm the diagnosis of yellow fever, a healthcare provider may order one or more of the following tests:

  1. Blood test: This test looks for antibodies produced by the body in response to the yellow fever virus. It can confirm the presence of the virus and help to distinguish yellow fever from other viral illnesses.

  2. Virus detection test: This test looks for the presence of the yellow fever virus in the blood or other body fluids, such as urine or saliva.

  3. Tissue culture: This test involves growing the yellow fever virus in the laboratory to confirm the diagnosis.

It is important to note that these tests may not be widely available or may not be reliable in all settings, particularly in areas where yellow fever is not common. In these cases, the diagnosis may be made based on clinical symptoms and a history of exposure to the virus.


If you suspect that you or someone you know may have yellow fever, it is important to seek medical attention as soon as possible. Early diagnosis and treatment can help to prevent severe illness and complications.

What is the treatment for yellow fever?

There is no specific treatment for yellow fever, but steps can be taken to relieve symptoms and support the body as it fights the virus. Treatment may include the following:

  1. Fluids: Dehydration is common in people with yellow fever, so providing fluids through intravenous (IV) fluids or oral rehydration solutions may be necessary.

  2. Medications: Pain medications, such as acetaminophen, may be given to help relieve fever and muscle aches. Antibiotics may also be prescribed to prevent or treat secondary infections.

  3. Close monitoring: Hospitalization may be necessary for severe cases of yellow fever, as the disease can progress quickly and can be fatal in some cases. Close monitoring of vital signs and other medical parameters can help to identify any changes in the patient's condition and allow for timely intervention.

  4. Oxygen therapy: In severe cases of yellow fever, oxygen therapy may be necessary to help the patient breathe.

Can yellow fever be prevented?

It is important to protect yourself from mosquito bites when traveling to areas where yellow fever is present. This can be done by using insect repellents, wearing long-sleeved clothing, and staying in accommodations with screens or air conditioning. There is also a vaccine available to prevent yellow fever, which is recommended for travelers to areas where the disease is present. It is believed that people who have had yellow fever develop lifelong immunity.

Is there a yellow fever vaccine?

Yes, there is a safe and very effective yellow fever vaccine available. The yellow fever vaccine is a live, attenuated vaccine that is administered by injection. It is highly effective at preventing yellow fever and has been shown to provide long-lasting immunity against the disease.


The yellow fever vaccine is recommended for travelers to areas where the disease is present, as well as for people who live in or work in these areas. It is also recommended for people who are at high risk of exposure to the virus, such as laboratory workers and healthcare workers.


The yellow fever vaccine is available through travel clinics and healthcare providers who are authorized to administer the vaccine. It is usually given as a single dose and provides immunity within a few days of vaccination. The vaccine is generally safe and effective, but like all vaccines, it can cause side effects in some people, including fever, headache, and muscle aches.


It is important to note that the yellow fever vaccine is not recommended for everyone, and it may not be suitable for people with certain medical conditions or allergies. It is important to discuss the risks and benefits of the vaccine with a healthcare provider before getting vaccinated.



Who is at risk for contracting yellow fever?

Anyone who travels to areas where yellow fever is present and is not protected by vaccination is at risk for contracting the disease. Yellow fever is found in certain parts of Africa and South America, particularly in areas with dense populations and poor sanitation, where the Aedes aegypti mosquito that transmits the virus is prevalent.


People who live in or travel to these areas are at increased risk of contracting yellow fever, especially if they have prolonged exposure to mosquito bites and do not take preventive measures to protect themselves. This includes travelers who visit forests, jungle areas, or urban environments where the virus is present, as well as people who work in these areas or who have long-term stays in these regions.


It is important for travelers to research the health risks associated with their destinations and to take appropriate precautions, including vaccination, to reduce their risk of contracting yellow fever or other infectious diseases.

How common is yellow fever in the world?

Yellow fever is not very common worldwide, but it is found in certain parts of Africa and South America. The World Health Organization (WHO) estimates that there are approximately 200,000 cases of yellow fever worldwide each year, with 30,000 deaths.


The disease is most common in tropical regions of Africa and South America, particularly in areas with high population density and poor sanitation.

What is the history of yellow fever?

Yellow fever has a long history and has been known to cause epidemics in Africa and the Americas for centuries.


The first recorded outbreak of yellow fever occurred in Yucatan, Mexico in 1648. The disease was later identified in the West Indies in 1685 and in Philadelphia, United States in 1793. In the 19th and early 20th centuries, yellow fever was a major public health threat in the United States, causing frequent outbreaks in the southern states and along the Mississippi River. It was also a significant factor in the construction of the Panama Canal, as many workers died from the disease during the construction process.


In the 20th century, significant progress was made in understanding the causes and transmission of yellow fever, and effective vaccines and other preventive measures were developed. As a result, the incidence of yellow fever has greatly declined in many parts of the world. However, the disease remains a significant public health threat in certain parts of Africa and South America, where outbreaks can still occur.

Can yellow fever be transmitted from person to person or is it only transmitted through mosquitoes?

Yellow fever is primarily transmitted through the bite of an infected mosquito. The virus that causes yellow fever is transmitted by the Aedes and Haemogogus genera of mosquito, which is found in certain parts of Africa and South America. The mosquito becomes infected with the virus when it bites a person who has yellow fever, and then it can transmit the virus to other people when it bites them.


Yellow fever is not transmitted directly from person to person. However, in rare cases, the virus can be transmitted through organ transplantation, blood transfusion, or laboratory exposure. Health care workers who come into contact with the blood or body fluids of infected patients may also be at risk of contracting the disease.


To reduce the risk of transmission, it is important to protect yourself from mosquito bites, especially when traveling to areas where yellow fever is present. This can be done by using insect repellents, wearing long-sleeved clothing, and staying in accommodations with screens or air conditioning. There is also a vaccine available to prevent yellow fever, which is recommended for travelers to areas where the disease is present.

Resources

[2] Kleinert, Robin DV, Eduardo Montoya-Diaz, Tanvi Khera, Kathrin Welsch, Birthe Tegtmeyer, Sebastian Hoehl, Sandra Ciesek, and Richard JP Brown. "Yellow fever: integrating current knowledge with technological innovations to identify strategies for controlling a re-emerging virus." Viruses 11, no. 10 (2019): 960. Download PDF

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