A 2016 outbreak of yellow fever in some regions of Angola, has led to renewed awareness of this disease. People in southern Africa want to know if they are at risk.
Yellow fever occurs in 34 countries in Africa and also in other countries such as China, Democratic Republic of Congo (DRC) and Kenya. Namibia and Zambia remain on high alert for imported cases.
In Angola an outbreak of yellow fever occurred in December 2015 in Luanda and since then the disease has spread to six of the country’s 18 provinces where it affected 450 and killed 178 people, according to the World Health Organisation (WHO). This situation is exacerbated by the fact that there currently is a shortage of vaccine against yellow fever.
What is yellow fever?
Yellow fever is an acute viral disease that causes bleeding. Some people suffering from the disease show signs of jaundice, hence “yellow” in the name of the disease. Unfortunately almost half of affected persons will die from yellow fever if they do not receive treatment.
How is yellow fever transmitted?
The yellow fever virus is one of the viruses that are transmitted by mosquitoes. Mosquitoes of the Aedes and Haemogogus species carry the virus from one host to another, usually between monkeys, from monkeys to humans, and also from humans to humans. The mosquitoes can breed around houses or in the jungle, that is, virtually anywhere.
Symptoms of yellow fever
Yellow fever takes between three and six days to incubate and grow in the body. Then the sufferer will have symptoms such as:
- Muscle pain with prominent backache
- Loss of appetite
- Nausea or vomiting.
These symptoms may disappear after 3 to 4 days.
After the initial remission phase, in 15% of sufferers a second and worse phase appears within 24 hours. The symptoms of this phase include:
- High fever
- Rapidly developed jaundice
- Abdominal pain
- Bleeding from the mouth, nose, eyes or stomach
- Blood in the vomit and faeces
- Deteriorating kidney function.
People who recover from this phase (about 50%) will have significant organ damage.
Yellow fever is difficult to diagnose, especially during the early stages. Blood tests can confirm the diagnosis by detecting yellow fever antibodies in the body.
Should you be concerned about yellow fever?
Unfortunately people living in Africa, travelling to Africa and especially those living near areas of outbreak are at higher risk of the disease. African data sources indicate that 84000–170000 cases of severe yellow fever occurred in 2013 and from these 29000–60000 people died.
There is no specific treatment for yellow fever. Only the symptoms are treated to make the sufferer more comfortable. The best way forward is to prevent the disease in the first place.
If you have been to a yellow fever area and you feel ill, or if you think you may have yellow fever, you are advised to consult a health professional immediately. Tell this person where you’ve been, if you’ve been bitten or if you think you may have been bitten by a mosquito. Do not take aspirin or ibuprofen as this may thin your blood.
What can you do to prevent yellow fever?
The most important prevention measure is the yellow fever vaccination. The WHO recommends routine infant immunisations (starting at 9 months of age) and mass vaccination campaigns in high-risk areas for all people of 9 months and older. People travelling to areas where the disease occurs, should also have the vaccination. The vaccine provides effective immunity within 30 days in 99% of persons vaccinated.
The vaccine is safe, affordable, and highly effective. A single dose of yellow fever vaccine is sufficient to give life-long protection against yellow fever.
Other preventative measures include the preventions of mosquito bites by:
- Covering up exposed skin by wearing long-sleeved shirts, long pants, socks, boots and hats
- Using an appropriate insect repellent as directed.
Yellow fever. Retrieved from http://wwwnc.cdc.gov/travel/diseases/yellow-fever
Yellow fever fact sheet, March 2016. Retreived from http://www.who.int/mediacentre/factsheets/fs100/en/
Yellow fever high alert for Southern Africa. Retrieved from http://www.medicalbrief.co.za/archives/yellow-fever-high-alert-for-southern-african/