Yellow fever is a viral infection transmitted by mosquitoes characterized by fever , jaundice, kidney failure and hemorrhage.
Causes, incidence, and risk factors
Yellow fever is caused by an arbovirus, a small virus transmitted by the bite of mosquitoes ( Aedes aegypti, Aedes africanus , and Haemagogus ). This disease is common in South America and in sub-Saharan Africa. Humans and monkeys are both hosts in the transmission cycle of this infection. While yellow fever can affect individuals of all ages, the elderly have a higher risk of severe infection. Symptoms usually develop 3 to 6 days after the mosquito bite. Yellow fever can be divided into three stages:
Early stage : headache , muscle aches , fever , loss of appetite , vomiting and jaundice are common.
Period of remission : fever and other symptoms resolve -- most individuals will recover at this stage, yet up to 15% may move onto the third, most dangerous stage.
Period of intoxication : characterized by multi-organ dysfunction -- liver and kidney failure, bleeding disorders/hemorrhage, brain dysfunction including delirium, seizures, coma, shock and in up to 20-30% individuals, death.
Signs and tests
A person with advanced yellow fever may show signs of liver failure, renal failure and shock. The diagnosis of yellow fever should be suspected in individuals with the symptoms listed above who have traveled to areas where the disease is known to thrive. The diagnosis is confirmed by detecting virus, viral antigens or antibodies in the blood.
Treatment
There is no specific treatment for yellow fever itself. Supportive measures which include intravenous fluids, blood products for severe bleeding and dialysis for renal failure may be needed.
Expectations (prognosis)
Yellow fever is a severe infection which may result in death in up to 40% of affected individuals.
Calling your health care provider
Seek medical attention at least 10-14 days before travelling to an endemic area for yellow fever to determine whether you should be vaccinated against yellow fever. Notify your health care provider right away if you or your child develop fever , headache , muscle aches , vomiting , or jaundice, especially if you have returned from an endemic area for yellow fever.
Prevention
Use of mosquito repellents, full covering clothing and screened housing is advised, as is vaccination if you will be traveling to an area where yellow fever occurs. Notify your health care provider at least 10-14 days prior to travel to determine whether you should be vaccinated against yellow fever.