Infectious Diseases – Yellow Fever

2 minutes

Alternative names: the yellow plague, yellow jack

 

Type of infection: viral

 

Incubation period: 3 to 6 days

 

Mortality rate: up to 50%, depending on severity.

 

Vector:  mosquito (specifically the Aedes aegypti species)

 

History

There are no recorded documentations about the origins or first outbreaks of yellow fever in Africa, though it became known to the medical community once it began traveling to the Caribbean via the slave trade. Several outbreaks happened on Barbados in the  mid 1600s, and there were further outbreaks in early colonial America not long after. As a major port city of the time, New Orleans saw its share of yellow fever in the mid 1800s as well.

In 1881, it was discovered that yellow fever is likely transmitted by mosquito and a vaccine was developed in the 1930s. Though vaccination programs have been implemented in many regions, the diseases continues to be a consistent threat in Africa today.

Catching Yellow Fever

Though a few other species can carry the disease, it’s mainly the Aedes aegypti that transmits yellow fever. You can’t get the disease directly from another infected person though it can seem to spread through a group because the local population of mosquitoes are carrying it. If an ill person is bitten, that mosquito can go on to infect other people.

Signs and Symptoms

The initial symptoms of yellow fever are fever, chills, nausea, loss of appetite, back pains and headache. After about a week, the symptoms will ease without further problems. But there is a more fatal phase after that, which does not occur in all patients. If the disease goes no further than this, then it is seldom fatal at all.

After the first round of symptoms, there can be abdominal pain and yellow skin can present as the liver starts to shut down. Then there can be bleeding from the nose or eyes, and there can be bloody vomit. This can lead to organ failure and death in about 50% of the cases that get to this point.

Treatment

There is no treatment for yellow fever due to its viral nature, except for medications that can ease the symptoms for comfort’s sake (such as ibuprofin for pain and fever). Drinking fluids is helpful to stay hydrated, and the patient should have bed rest.

Prevention

There is a common vaccine available to combat yellow fever, and it is often a requirement for anyone traveling to areas where the disease is endemic. It should be easy enough to get if you feel that this is a potential threat in your area.

If unvaccinated, you can protect yourself from yellow fever by reducing exposure to mosquito bites in the usual manner. Long sleeved shirts and pants should be worn when outside, and insect repellent is a must.

Risk Assessment

It is mostly a disease found in Africa, but as the Aedes aegypti mosquito finds more northern habitats, it can start to spread even further (including southern United States). Worldwide, there are 200,000 cases of yellow fever each year, with 90% of those being in Africa. The rest are mainly across the Caribbean and South America. So there is certainly a reservoir of the disease out there, which could lead it northward to North America if the mosquito changes habitats.