Yellow fever is a potentially lethal acute viral haemorrhagic disease. It is transmitted by mosquitoes, mainly of the genus Aedes or Haemagogus, and has an incubation time of 3 to 6 days. Seven genotypes of yellow fever virus have been identified, two of which are found in South America and five in Africa.
How did yellow fever originate?
According to the Centers for Disease Control and Prevention (CDC), yellow fever originated about 3,000 years ago in Africa. Throughout the 16th century, the disease reached the Western Hemisphere through the slave trade. Later, it reached Europe, where it claimed thousands of victims in outbreaks that occurred first in Cadiz, Spain and later in English and French ports.
Today, the yellow fever vaccine is part of routine immunizations for infants in regions at higher risk of transmission, such as Africa and South America. Despite these efforts, hundreds of cases are still reported each year. That’s why prevention of this disease is so important for travellers heading to an endemic destination.
What are the symptoms of yellow fever?
In most cases, the infection is asymptomatic. However, patients may experience the following symptoms:
- Fever
- Headache
- Chills
- Muscle pain
- Nausea
- Vomiting
Approximately 15% of cases become severe and have bleeding symptoms, as well as jaundice and multi-organ dysfunction syndrome.
What is the treatment for yellow fever?
There are no medications to specifically treat this condition, so treatment is focused on relieving symptoms and includes rest, fluids, pain relievers, and antipyretics, which may reduce fever and pain. Yellow fever can be prevented by vaccination. All vaccines currently produced are live attenuated, meaning they contain a weakened form of the virus, which stimulates the immune system without causing disease. The application is in a single subcutaneous dose of 0.5 ml.
What is the risk of getting yellow fever?
The CDC states that the risk of yellow fever infection for people who are not vaccinated during a two-week visit to a destination where the disease is endemic is 50 per 100,000 in West Africa and 5 per 100,000 in South America. The risk of death from this disease is 10 per 100,000 and 1 per 100,000 respectively.
