About Everything You Need to Know About Yellow Fever

If you are a frequent traveler or are planning to travel outside the United States, besides the obvious risks that are involved with travel there is something else you should worry about: Yellow Fever.

This virus can do serious damage to your body and your internal organs, so you have to ready and take certain precautions when getting ready to travel outside your country and into those possible areas.

While Yellow Fever Virus is generally not a threat in most countries, due to close proximity to jungle and savannah like environments it is prominent in Central and South America, as well as most countries in Africa.

The virus is most commonly spread by mosquitoes. There are two ways that you can be infected with the virus: primate-to-mosquito-to-human or human-to-mosquito-to –human. Either infection will most likely have the same result.

Symptoms

The symptoms associated with Yellow Fever Virus are lack of appetite, fever, chills, nausea, muscle pains (usually in the back area), and severe headaches. Usually, these symptoms subside within five or days or so.

The disease is an acute viral disease, meaning it is rather short and acts quickly. It targets your RNA and is part of the Flavivirus genus. West Nile Virus belongs to this same genus.

Because of how common the symptoms of YFV are, it can be very difficult to tell if the symptoms are related to YFV or to another disease, especially in its early stages. A blood test is required to confirm if the symptoms are due to a Yellow Fever Virus infection or not.

History

Roughly 200,000 infections occur yearly due to the yellow fever virus. Out of those 200,000 infections, about 30,000 result in death.

The virus originated in Africa and around the 17th century, because of the slave trade, it was spread to South America.

Since then, there were many outbreaks recorded in the Americas, Europe, and Africa, resulting in it becoming one of the most dangerous infectious diseases of the 18th and 19th centuries.

Cycles

There are three different infection cycles that occur with Yellow Fever Virus. The first cycle is the “urban” cycle, which is only caused by the yellow fever mosquitoes.

It is well adapted to urban areas where there are a lot of people. This cycle is responsible for most outbreaks in Africa. Although there was an outbreak in 1999 in Bolivia, the urban cycle no longer exists in South America.

The sylvatic cycle is the second infection cycle, which occurs in both Africa and South America. This is the forest or jungle cycle in which mosquitoes serve as a vector. Mosquitoes, which are carriers of the yellow fever virus, infect many primates which then present as asymptomatic.

This means that the primates show no symptoms of infection. It is due to this cycle type that the yellow fever virus cannot be eradicated.

There will always be infected primates in the jungle which can infect more mosquitoes that can transfer the virus to humans.

The last infection cycle is also localized only to Africa. It is known as the savannah cycle. It is similar to the sylvatic cycle, but a different set of mosquito carriers is involved.

In the savannah cycle, mosquitoes from the genus Aedes are involved in infecting and thus spreading the virus to humans and primates. This has been the most common infection cycle in Africa in recent years.

Travel to Countries At Risk Of Yellow Fever

Obviously the best way to avoid infection is by staying away from the countries which carry the risk of Yellow Fever Virus infection. If you are planning on traveling to any of these countries, a vaccination is definitely a must to prevent yellow fever.

Those who live outside of the risk countries are more likely to be infected and show more powerful symptoms than the local residents of these countries.

The main reason for this is because resistance to infection is developed over time by those who live in the risk prone countries. Resistance also increases as a person gets older. This is the reason why younger people are more susceptible to infection than adults.

Protection from infection starts about 10 days after vaccinations and last for an astounding ten years. Furthermore, roughly 80% of people are still immune after thirty years.

For those who live in the infection risk areas, it is suggested that regular vaccinations are done between the ninth and twelfth month after birth.

A quarter of all vaccinated people will experience fevers, aches, and soreness, as well as redness at the spot of vaccination.

Controlling & Reducing the Risk of Yellow Fever

Since 2009 the amount of vaccinated people has been calculated at around 12 million in West Africa, but it is estimated that this is still not enough to eradicate the virus.

However, it will certainly reduce the amount of infections and the chance to spread through the urban cycle infection method.

This mass vaccination method is only a small dent in the potential infected people and the World Health Organization (WHO) states that if they don’t receive further funding for more mass vaccinations, there could soon be as many as 160 million people at risk of infection on the continent.

Even though a single vaccination is only estimated to last ten years, WHO has stated that one dose of vaccination could be sufficient to create life-long immunity against the Yellow Fever disease.

Another way to control the infections is by reducing the populations of the vector mosquitoes.

This is not only beneficial to control YF infections but also affect many other potential infections, such as dengue fever.

Most mosquitoes breed in water, usually old tires that have standing water in them, or perhaps cans or bottles. Basically anywhere where still water is present can be a potential ground for these mosquitoes to breed.

In some locations, the use of larvicides has been the primary method of fighting the spread of these mosquitoes. Others have been using larva eating fish and copepods, a type of small crustaceans, to reduce the amount of larva found in these still water locations.

Targeting the larva has proven to be a more effective methods to control the populations of these mosquitoes.

Which Countries are at Risk of Yellow Fever?

Yellow Fever is to be taken seriously. It has been the source of serious problems and issues for many people in the past and is still a very serious risk to many others.

We urge you to vaccinate yourself well ahead of time if you are planning to travel to any of the countries which are at risk for yellow fever infections.

Even if you are visiting the neighboring countries, we still suggest vaccination just in case. Give yourself plenty of time to make sure the vaccine is in full effect when you start your travels.

Countries at moderate or high risk of YFV transmission:

Africa:

  • Angola
  • Benin
  • Burkina Faso
  • Burundi
  • Cameroon
  • Central African Republic
  • Chad
  • Republic of the Congo
  • Côte d’Ivoire
  • Democratic Republic of the Congo
  • Equatorial Guinea
  • Ethiopia
  • Gabon
  • Gambia
  • Ghana
  • Guinea
  • Guinea-Bissau
  • Kenya
  • Liberia
  • Mali
  • Mauritania
  • Niger
  • Nigeria
  • Senegal
  • Sierra Leone
  • South Sudan
  • Sudan
  • Togo
  • Uganda

Central and South America:

  • Argentia
  • Bolivia
  • Brazil
  • Colombia
  • Ecuador
  • French Guiana
  • Guyana
  • Panama
  • Paraguay
  • Peru
  • Suriname
  • Trinidad and Tobago
  • Venezuela

Countries at low risk of YFV transmission:

The following countries are considered at low rich of Yellow Fever, but should still be considered among those you should vaccinate before travelling to.

  • Eritrea
  • Rwanda
  • São Tomé and Príncipe
  • Somalia
  • Tanzania
  • Zambia