What is Yellow Fever?

The question ‘What is Yellow fever’ is quite general and carries numerous sub questions in order to define it. The most basic definition of Yellow fever is that it is a viral disease. The technical response to this would be that it is a virus of the Flaviviridae family which are a group of viruses that are spread through insects such as ticks and mosquitoes.
Yellow fever has been around for hundreds of years but it took until the 19th Century for a man known as Walter Reed to prove the theory that the virus was spread by mosquitoes and not through direct human contact with sufferers or their bodily fluids.

In 1937, Max Theiler developed the first vaccine for Yellow fever. This vaccine is still used today on millions of people both indigenous to risk areas and worldwide for those who wish to travel there.

Yellow fever severity is split into two sections; the acute stage and toxic stage. The acute stage is marked by minor symptoms that appear mostly flu like. If a person is going to enter the toxic stage of the disease it is normally within 24 hours of entering the acute stage. This second stage is potentially fatal and can cause liver failure, and bleeding.

The survival rate for Yellow fever has changed and varied over the years with some difference of opinion between surveys. Most will accept that around 15% of people will enter the toxic stage of the disease and of these people at least 20% will die. There is the opinion that this number of fatalities can reach as high as 50% in some cases.
Research for the Yellow fever is forever expanding and there have been some recent calls for further funding in this area due to an increase in the number of cases and epidemic occurrences.

There is no cure for Yellow Fever and so treatment is limited to providing relief for the symptoms exhibited. Vaccination in this case is necessary and you will not be permitted to travel to risk areas without proof of vaccination.

The mosquito that carries the Yellow fever virus is known as Aedes Aegypti, part of the same historical family as the Anopheles genus which are known to carry malaria. Unlike its nocturnal counterpart, the yellow fever mosquito feeds only during the day. It is drawn to well populated, urban areas which are naturally abundant in its favourite food source.

If you plan to travel to an area where Yellow fever is a risk, such as Africa or South America, make sure you plan ahead for your Yellow fever vaccination. Remember, immunisation takes effect around 10 days after vaccination and lasts for 10 years. So make sure you get vaccinated as early as possible before your holiday, just to be safe.