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Yellow fever Causes and Risks:
Yellow fever is caused by an arbovirus (Flaviviridae), a small RNA virus that is transmitted by the bite of mosquitoes (Aedes aegypti, Aedes africanus, and Haemagogus). Areas of high incidence are Central America, the northern half of South America, and Central Africa.
Mild subclinical infection occurs and may be more common in children. The acute form of the disease causes headache , muscle aches , fever , loss of appetite , and vomiting . The infected person may also develop a red tongue, flushed face , and reddening of the eyes. By the fifth day, jaundice (the yellow color of the skin for which the disease is named), stomach pain , and bleeding (which may appear as bloody vomiting) develops. Delirium and seizures followed by coma are common. Death occurs at the end of the first week of symptoms and as many as half of the infected people may die.
Prevention:
Vaccination is the only sure prevention for yellow fever. Use of mosquito repellents, full covering clothing and screened housing will decrease exposure risk. Mosquito control has decreased the risk in countries where the disease was once prevalent. The risks remain however, because the mosquito has increasing resistance to insecticides . DDT is very effective, but production has been discontinued in many areas.
Symptoms:
Signs and Tests:
The affected person may show signs of: Tests:
Treatment:
There is no specific treatment for yellow fever. The present treatment is supportive.
Intravenous fluids are given to treat dehydration , hypotension ( low blood pressure ), and hypoglycemia ( low blood sugar ). Antacids and H2 histamine blockers are often prescribed to protect the stomach from bleeding . Medications such as acetaminophen are used for fever control.
Dialysis may be needed if kidney failure develops. Transfusions of fresh blood, or plasma transfusion, may be needed to control severe bleeding disorders .
Prognosis:
Yellow fever is a dangerous illness without specific therapy the death rate remains high, even with good supportive care.
Complications:
Call Your Healthcare Provider:
Call for an appointment with your health care provider if you are planning a trip to an area where yellow fever is common ( endemic area).
If you live in (or you have visited) an endemic area and your child develops fever , headache , muscle aches , and vomiting , call your health care provider immediately.
There are many different species of mosquito, some of which carry some of the worlds most common and most economically important infectious diseases. Malaria and yellow fever are two of the most important diseases they carry. Others include encephalitis (viral), dengue fever, and leishmaniasis. (Courtesy of the Centers for Disease Control.)
This illustration shows an adult southern house mosquito. This mosquito feeds on blood and is the carrier of many diseases, such as malaria, dengue fever, yellow fever, and others. (Courtesy of the Centers for Disease Control.)
Mosquitoes lay their eggs in still or stagnant water. The eggs hatch into a carnivorous larval stage before developing into flying mosquitoes. (Courtesy of the Centers for Disease Control.)
This picture shows mosquito larvae, most of which will become blood-sucking, disease-carrying mosquitoes. (Courtesy of the Centers for Disease Control.)
These are mosquito pupa. This is another stage in the development of the mosquito. (Courtesy of the Centers for Disease Control.)
Jaundice results when bilirubin, a yellowish pigment, builds up to high levels in the blood stream. Bilirubin is a breakdown product of hemoglobin, the red oxygen-carrying pigment found in red blood cells (RBCs). The liver and biliary system are responsible for ridding the body of bilirubin. Jaundice usually indicates liver disease or obstruction of the biliary system.
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