Yellow fever is a disease characterized by fever and bleeding. It is a mosquito-borne disease which means mosquito is the vector or vehicle in transmitting this disease from one human to another. The yellow disease may cause kidney failure, liver failure, coagulation disturbances, and shock. This disease is endemic in South America and sub-Saharan countries. In other words, yellow fever is very common in those countries and any travellers who go to those countries can easily suffer from yellow fever. That’s why immunization is required if you decide to travel to those countries. Yellow fever is a viral disease. Yellow fever is caused by a virus that belongs to the Flaviviridae family. Yellow fever prevention is so important for anyone who is travelling to countries with a high number of yellow fever cases.

Yellow fever virus causes large outbreaks (sudden and a lot of increase in new cases) in Brazil (2016 to 2018) and Africa (2015 to 2016). One per cent of patients with severe liver disease in countries where yellow fever is endemic are due to yellow fever. In 2013, 78,000 deaths were reported in Africa. Yellow fever outbreak has never been reported in Asia. Aedes mosquitoes are the responsible vector of this disease. Aedes mosquitoes are also the vector for dengue fever in Asia. Eradication of these mosquitoes will help to prevent the transmission of yellow fever. The onset of yellow fever is around three to six days after mosquito bites.

The clinical features are:

  • Fever
  • Malaise
  • Headache
  • Photophobia
  • Back pain
  • Leg pain
  • Nausea
  • Vomiting
  • Anorexia
  • Body and muscle ache
  • Dizziness
  • Restlessness
  • Irritability
  • Abdominal pain
  • Red skin and gums
  • Jaundice
  • Bleeding
  • Low urine output
  • Bruises
  • Delirium
  • Agitation
  • Seizure

A physical examination along with history taking and investigations are important in confirming the diagnosis of yellow fever. The investigations that can be done are:

  • Enzyme-linked immunosorbent assay (ELISA)
  • Polymerase chain reaction (PCR)
  • Virus detection and isolation

The diseases that may mimic Yellow fever are:

  • Hepatitis A
  • Hepatitis B
  • Hepatitis C
  • Hepatitis D
  • Hepatitis E
  • Influenza
  • Dengue
  • Malaria
  • Typhoid
  • Leptospirosis
  • Q fever
  • Ebola virus infection
  • Marburg virus infection
  • Lassa fever
  • Bolivian and Argentine hemorrhagic fever
  • Dengue hemorrhagic fever
  • Congo-Crimean hemorrhagic fever
  • Rift Valley fever

The treatment of yellow fever mainly consists of supportive care. There is no specific treatment or specific antiviral treatment available. Modern intensive care is good to handle cases of yellow fever. However, this treatment is not available in rural and remote areas in Africa and South America due to a lack of facilities and expertise. Although modern intensive care is good enough to save patients with yellow fever, some of the patients with severe yellow fever still can’t be safe and died.

Supportive care includes:

  • Nutrition
  • Prevention of low blood sugar level (hypoglycemia)
  • Nasogastric suction to prevent any unwanted contents enter the airway
  • Prevention of low blood pressure or hypotension by giving intravenous fluids and medications if needed
  • Oxygen therapy
  • Prevention of seizure
  • Treatment of bleeding
  • Treatment of metabolic acidosis
  • Treatment for other existing infections
  • Dialysis if needed

Antiviral therapy is still new and in the development phase. Only ribavirin has proven effective in treating yellow fever but only up to a certain extent. Vaccination is the main way to prevent yellow fever. Get yourself vaccinated before going to countries that are affected by yellow fever.