Hesperian Health Guides

Yellow Fever

Every day 20,000 people visit the HealthWiki for lifesaving health information. A gift of just $5 helps make this possible!

Make a giftMake a gift to support this essential health information people depend on.

HealthWiki > A Community Guide to Environmental Health > Chapter 8: Health Problems from Mosquitoes > Yellow Fever

Yellow fever is carried by mosquitoes in Africa and some parts of South America. There are two kinds of yellow fever and they spread in different ways:


Jungle yellow fever is spread from infected mosquitoes to monkeys, and back again from monkeys to mosquitoes. People get infected when they are bitten by mosquitoes that have been infected by monkeys. Jungle yellow fever is rare and mostly affects people who work in tropical rain forests.

Urban yellow fever is the cause of most yellow fever outbreaks and epidemics. Like malaria and dengue, urban yellow fever spreads when a mosquito bites and sucks the blood of an infected person, and then passes the infection to the next person it bites.

Urban yellow fever is spread by the same black mosquito that spreads dengue. It has white dots along its back and legs. These mosquitoes live and breed in standing water in cities, towns, and villages.

Man shaking.

Yellow fever causes fever, chills, muscle pain (especially backache), headache, loss of appetite, nausea and vomiting, high fever and slow pulse. For most people, the illness goes away after 3 or 4 days.

But for some people, about 1 out of every 7, the fever returns 24 hours after the first signs go away. Jaundice, abdominal pain, and vomiting may be followed by bleeding from the mouth, nose, eyes, and stomach. Death may occur within 10 to 14 days, but half of the people sick with this second round of yellow fever survive with no serious damage to their health.

water container, barrel, and pile of tires, all covered.
To help prevent yellow fever, get rid of places where mosquitoes can breed and keep water containers covered.

The best treatment for yellow fever is bed rest and drinking plenty of fluids. Most people recover completely over time and develop a resistance to it. A small number of people do get the disease again, before they have recovered from getting it the first time. But they too usually recover.


Like malaria and dengue, the best way to prevent yellow fever is to avoid mosquito bites and control mosquitoes. Vaccination is the only sure prevention for yellow fever, but may not be available or may be expensive.