Yellow fever

Yellow fever (also called yellow jack, black vomit or sometimes American Plague) is an acute viral disease. It is still an important cause of hemorrhagic illness in several African and South American countries despite existence of an effective vaccine. In the past it was a source of several devastating epidemics. As of 2005, the World Health Organization (WHO) estimates that yellow fever causes 200,000 illnesses and 30,000 deaths every year in unvaccinated populations.

Related Topics:
Viral - Hemorrhagic - Africa - South America - Vaccine - World Health Organization

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The disease is caused by an arbovirus of the family Flaviviridae, and is one of the smallest RNA viruses isolated from man.

Related Topics:
Arbovirus - Flaviviridae

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Mosquitos are the primary vector in transmission of the disease from forest monkeys to humans and in person-to-person transmission. The mosquitos involved are Aedes simpsoni, Aedes africanus, and Aedes aegypti in Africa; and the Haemagogus and Sabethes genera.

Related Topics:
Mosquito - Vector - Monkey - Aedes simpsoni - Aedes africanus - Aedes aegypti - Haemagogus - Sabethes

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The course of the disease varies from an unapparent infection to an intense feverish illness with high mortality rate. There is a difference between disease outbreaks in rural or forest areas and in towns. Disease outbreaks in towns and non-native people are usually more serious.

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After a 3 to 6 day incubation period the typical symptoms that arise are fever, muscle aches, headache and backache. Other symptoms may include a red tongue, flushed face, and reddening of the eyes. In a proportion of cases there is also involvement of internal organs - liver, kidneys and the heart. There may be hemorrhage from the digestive tract (bloody vomit). Later the disease is sometimes complicated by jaundice with liver failure and/or renal insufficiency with proteinuria. If the disease progresses, delirium, seizures and coma ensue. Hypotension and dehydration are also common. Mortality is around 5%. Patients who die usually do so within six to seven days from the onset.

Related Topics:
Incubation period - Fever - Headache - Liver - Kidneys - Heart - Hemorrhage - Digestive tract - Jaundice - Proteinuria - Delirium - Seizure - Coma - Hypotension - Dehydration

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