Yellow fever – Here is Everything You Should Know
Yellow fever is an acute virus disease transmitted by infected mosquitoes. In cities, it is spread primarily by Aedes aegypti, a type of mosquito found throughout the tropics and subtropics. The virus is an RNA virus of the genus Flavivirus. Mosquitoes become infected with the virus when they bite an infected human or monkey. The disease cannot be spread by contact from one person to another.
When the human body and virus contracted, then the yellow fever virus incubates in the body for 3 to 6 days. Symptoms usually present themselves in 2 phases.
Symptoms in the First Phase
- Back pain
- Loss of appetite
- Muscle pain
In most cases, symptoms disappear after 3 to 4 days. After 24 hours a small percentage of patients may enter into a second phase.
In this phase high fever returns and several body systems are affected, usually the liver and the kidneys. In most cases people are likely to develop jaundice that will leads to the yellowing of the skin and eyes, hence the name ‘yellow fever’, dark urine and abdominal pain with vomiting. Bleeding can occur from the mouth, nose, eyes or stomach. Half of the patients who enter the toxic phase die within 7 – 10 days.
Diagnosis of the yellow fever virus is difficult especially during the early stage. Blood tests (RT-PCR) can sometimes detect the virus in the early stages of the disease. In later stages of the disease, testing to identify antibodies is needed (ELISA and PRNT).
- Mosquito control
- Epidemic preparedness and response
Currently there is no cure is known for yellow fever but specific care to treat dehydration, liver and kidney failure, and fever improves outcomes. Associated bacterial infections can be treated with antibiotics. Hospitalization is advisable and intensive care may be necessary because of rapid deterioration in some cases.
Yellow fever occurs in 47 endemic countries in Africa in Central and South America. Around 90% of cases reported every year occur in Sub-Saharan Africa. In 2013, yellow fever resulted in about 127,000 severe infections and 45,000 deaths, with nearly 90% of these occurring in African nations. The disease originated in Africa, from where it spread to South America through the slave trade in the 17th century.