- Thomas P Monath. Yellow Fever. UpToDate, last update April 13, 2016
- Martins E. Ssekweyama. Residents to get yellow fever vaccine. Daily Monitor, April 20, 2016
What is yellow fever?
Yellow fever is a virus that can cause infection in humans and monkeys. In some humans, yellow fever results in severe illness or death. Yellow fever virus is a member of the Flaviviridae family, which includes Dengue, Zika and West Nile viruses. The virus is transmitted by a mosquito of the Aedes species that bites in the afternoon. Transmission occurs from sick humans or monkeys to other monkeys or humans. Furthermore, the Aedes mosquitos can pass on the virus to the next generation in their eggs. Transmission from human to human in the absence of the mosquito does not occur.
Where is yellow fever?
Yellow fever occurs in tropical regions of sub-Saharan Africa (including Uganda) and South America. Currently, there is an on-going epidemic in Angola that began in December 2015 and caused hundreds of deaths. Furthermore, the ministry of health in Uganda reported an outbreak of yellow fever in Masaka district this year. Since the outbreak that started early March 2016, there are 10 registered deaths due to yellow fever in Uganda. The ministry of health is planning a massive immunization campaign in the Masaka district to contain the spread of the disease (see information about prevention below).
N.B. Yellow fever has never been reported in Asia, and introduction to that region could have devastating effects because the mosquito responsible for transmission of yellow fever is present in large numbers. Some countries (where the Aedes mosquito is present) have put strict immigration controls into place that require quarantine for individuals arriving from African countries (including Uganda) without a valid certificate of immunization.
What are the symptoms of yellow fever infection?
Not all patients with yellow fever have the same symptoms. Some patients don’t have any symptoms at all, some only have fever, others become very ill and some patients die. People of older age are more likely to die from yellow fever. Usually, it has three stages: 1) period of infection; 2) period of remission; 3) period of intoxication.
1) The first symptoms start three to six days after the bite of an infected mosquito. Possible symptoms are: fever, generalized malaise, headache, sensitivity to light, lower back pain, pain in the legs (particularly the knee joints), muscle pain, loss of appetite, nausea and vomiting, restlessness, irritability and dizziness. The period of infection lasts three to four days (this is also the phase in which transmission of the virus from infected human to mosquitos is possible).
2) A period of remission lasting up to 48 hours may follow the period of infection, characterized by the absence of fever and symptoms. Most patients recover at this stage. Approximately 15% of individuals infected with yellow fever virus enter the third stage of the disease.
3) The period of intoxication begins on the third to sixth day after the onset of infection with return of fever, nausea, vomiting, abdominal pain, yellow eyes, reduced urinary output, bleeding from different body sites and eventually shock. These symptoms are due to dysfunction of different organs (such as liver, kidneys and heart). Approximately 20-50% of patients who enter the period of intoxication die from yellow fever. In patients that recover, fatigue and yellow eyes may last for weeks.
How is yellow fever infection diagnosed?
In case of suspected yellow fever, the disease can be confirmed with a blood test.
How is yellow fever infection managed?
There is no specific medication to treat yellow fever. The treatment consist of supportive care, such as administration of drugs to reduce the fever, keeping the blood pressure up with a drip, administration of oxygen if needed, blood transfusion in case of bleeding and kidney dialysis if the kidneys are shutting down.
Yellow Fever Prevention
Although there is no specific treatment for patients infected with yellow fever, as said before: a vaccine to prevent yellow fever is available! Vaccination is recommended for all residents of countries with a risk of the infection (including Uganda), and for travellers to these areas. The vaccine may be administered to individuals over the age of nine months and according to recent studies, only a single dose is needed for lifelong protection against the virus. The requirement for a booster dose 10 years after first immunisation will officially be dropped by June 2016.
Where can I get yellow fever vaccination?
The Surgery Uganda provides the yellow fever vaccine together with the WHO International Certificate of Vaccination.
For further information please call us on +256 (0) 31 225 6001/2/3 or +256 (0) 772 756003. Our vaccine room is open Monday – Friday from 08.00 – 17.00 and on Saturdays from 09.00 – 15.00, no need to make an appointment.