Yellow fever

Type of disease

Hemorrhagic fever

Pathogen (cause)

Yellow fever virus

Transmission

The virus is transmitted via infected yellow fever mosquitoes, also known as Egyptian tiger mosquitoes or Aedes aegypti - day and night.

Regions of risk

Tropical Africa, Central and South America

Rates of infection

There are about 200,000 cases of yellow fever per year, with 30,000 resulting in death. Ninety percent of cases occur in Africa.

Duty to report

Yes

Variations

A form of "jungle" yellow fever - commonly referred to as yellow fever - can be transmitted by mosquitoes between apes living in the wild, and also transmitted to humans.

In urban areas, the virus is also transmitted by mosquitoes between humans.

Incubation period

Three to six days after infection.

Symptoms and how they progress

Mild symptoms occur in 85 percent of cases. Patients experience a 40 degree fever, shivering, headaches, pain in the limbs and muscles, nausea and vomiting.

Severe symptoms occur in 15 percent of cases. There are two phases.

Phase one: vomiting bile, diarrhea, extreme thirst, mild jaundice, bleeding gums, low levels of urine.

Phase two: hemorrhaging of the skin and mucous membranes, acute liver failure, blood and fluid loss, acute kidney failure, failing detoxification, neurological symptoms. Death can occur on the sixth or seventh day due to multiple organ failure, with bleeding all over the body.

Death rate

Between 50 and 60 percent of patients presenting severe symptoms die.

Treatment

There is no specific treatment for yellow fever - only the symptoms can be treated.

Prevention

Vaccination and protection against mosquito bites.