Yellow fever is a serious disease caused by the
yellow fever virus. It is found in certain parts of Africa and South America.
Yellow fever is spread through the bite of an infected mosquito.
Mosquitoes become infected when they feed on infected humans or monkeys. Infected mosquitoes can then spread the virus to humans when they bite.
Yellow fever is not contagious, meaning it is not passed directly from humans to other humans. It is not spread through casual contact, such as touching or kissing a person with the virus.
Transmission of the virus occurs in two main ways: urban (mosquito bites an infected human) and sylvatic (mosquito bites an infected monkey).
When a person becomes infected with the yellow fever virus, the virus begins to multiply inside the body. After three to six days, the symptoms of yellow fever can occur. This period between becoming infected and the start of symptoms is called the incubation period.
Yellow fever symptoms vary among individuals. Some will have no symptoms, others may develop flu-like symptoms, and some may develop very serious symptoms, including death.
In order to make a diagnosis, your doctor will ask questions about a number of things (including recent medical and travel history), perform a physical exam, and recommend certain tests. As part of diagnosing a
yellow fever virus infection, the doctor will also rule out other, more common causes of symptoms, such as
the flu or
common cold.
Tests the doctor may order to help diagnose the disease can include:
- Blood tests
- Cerebrospinal fluid tests
- Electrocardiogram (EKG).
These individual tests will not definitely diagnose yellow fever, but they can be helpful. To make a definitive diagnosis, the doctor will draw a blood sample and send it to a commercial or public health laboratory for confirmation.
There is currently no treatment that can kill the virus. Therefore, treatment is focused on providing relief of symptoms as the body fights the virus.
Most people recover without any long-term effects from the yellow fever infection. The overall death rate is estimated to be between 5 and 10 percent; however, research scientists and doctors believe that the death rate might even be less. In a number of cases, the infection causes no symptoms, or very mild symptoms, and people do not seek medical attention.
Vaccination and Other Prevention Strategies
The best way to prevent this disease is with the yellow fever vaccine. Yellow fever is a very rare cause of illness in travelers, but most countries have regulations and requirements for vaccination that must be met prior to entering the country.
Preventing mosquito bites also reduces your risk of getting yellow fever, along with other diseases that
mosquitoes can carry. Take the common-sense steps to reduce your risk, including the use of:
- Insect repellent
- Protective clothing
- Mosquito netting.
The first identified outbreak of yellow fever is believed to have occurred in Yucatan in 1648. In the more than 200 years that followed, yellow fever was considered one of the great
plagues of the world. As late as 1905, many southern cities in the United States experienced several thousand cases and approximately one thousand deaths per year.
One of the most famous yellow fever epidemics occurred in Philadelphia in 1793. This epidemic led to over 5,000 deaths within Philadelphia (about 10 percent of the population). About half of the residents had fled the city during the summer of 1793. Philadelphia experienced several more outbreaks (1796 and 1797), but these were not as severe. In 1798, Philadelphia experienced another severe yellow fever epidemic, killing 1,292 Philadelphians.
More Yellow Fever Information
Certain yellow fever topics that were mentioned previously have a hyperlink to additional eMedTV articles. Click on the specific link to view the article. Other eMedTV articles on yellow fever include:
