If your future travel plans include Africa, the Caribbean or Central or South America, it’s important to be aware of the risk of contracting yellow fever.
In this guide we cover the history, transmission, treatment and, most importantly, the vaccination requirements for travellers.
What is yellow fever?
Yellow fever is a viral haemorrhagic disease, transmitted primarily by mosquitoes, which can lead to serious illness and death. It is called yellow fever because in severe cases, the skin turns yellow.
There are three types of yellow fever:
- Sylvatic (or jungle) yellow fever occurs when the disease is transmitted from infected monkeys to humans via wild mosquitos
- Intermediate yellow fever occurs when semi-domestic mosquitoes are present in an area where they come into contact with humans
- Urban yellow fever occurs when the Aedes aegypti species of domestic mosquito transmits the virus between humans in densely populated urban areas
When was yellow fever first discovered?
Yellow fever has the infamous distinction of being the first human virus discovered. It is thought to have originated in East or Central Africa with transmission of the virus occurring from primates to humans.
It was most likely transferred to North and South America with the importation of slaves from Africa. The first definitive outbreak in the New World was in 1647 on the island of Barbados, while the first mention of the disease by the name “yellow fever” occurred in 1744.
In the 18th and 19th centuries yellow fever was considered one of the most dangerous infectious diseases known to mankind.
How many people contract it every year?
The year with the most reported cases was 1988 when more than 5 million cases were recorded. Nowadays, there are an estimated 200,000 cases of yellow fever worldwide each year and between 30,000 and 60,000 deaths with 90% of these occurring in Africa.
Which populations are most at risk?
Almost a billion people in 44 countries in Africa and Latin America (including Bolivia, Brazil, Colombia, Ecuador and Peru) are at risk.
North America and Europe have experienced outbreaks of yellow fever in the past, such as the yellow fever epidemic that gripped Philadelphia in 1793, killing almost 10% of the population.
What are the symptoms?
It takes three to six days for symptoms to appear. During the acute phase, an infected person will usually experience fever, muscle pains, backache, headaches, shivering, loss of appetite, nausea and vomiting. For many, these symptoms disappear within three or four days.
Around 15% of patients who enter the remission phase will enter a second phase within 24 hours. This more toxic and dangerous phase can cause death within two weeks. Symptoms include severe fever, jaundice, abdominal pain, vomiting and even bleeding from the mouth, nose, eyes or stomach.
Unfortunately, yellow fever is difficult to diagnose during the early stages as it can be confused with malaria, viral hepatitis, other haemorrhagic fevers and even some poisons.
How is yellow fever treated?
The bad news is that, while medicines can help to relieve the symptoms, there is no cure and no specific treatment for yellow fever.
How can I avoid contracting yellow fever when traveling?
The good news is that yellow fever is preventable. A safe and effective vaccine is available and is almost 100% effective.
If the “almost” part concerns you, take extra precautions to avoid mosquitoes. The mosquitoes that transmit yellow fever are usually active during the day, so while a mosquito net over your bed is great, you should also ensure you have a strong mosquito repellent (containing either DEET or Picaridin) on during the day, and that you wear light coloured clothes that cover your arms and legs when outdoors.
Where can I get my vaccination?
The 1st Contact travel Clinic – one of London’s most well-known vaccination centres– offers excellent travel advice, vaccinations and certificates, fact sheets and travel accessories for the prevention of illness.