Yellow fever overview: Difference between revisions
| Line 21: | Line 21: | ||
==Epidemiology and Demographics== | ==Epidemiology and Demographics== | ||
Yellow fever occurs in sub-Saharan Africa and tropical South America, where it is endemic and intermittently epidemic. Urban yellow fever occurs periodically in Africa and sporadically in the Americas. In Africa, natural immunity accumulates with age, and thus, infants and children are at highest risk for disease. In South America, yellow fever occurs most frequently in unimmunized young men who are exposed to mosquito vectors through their work in forested areas. | |||
==Risk Factors== | ==Risk Factors== | ||
Revision as of 21:15, 23 December 2014
|
Yellow fever Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Treatment |
|
Yellow fever overview On the Web |
|
American Roentgen Ray Society Images of Yellow fever overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Alejandro Lemor, M.D. [2]
Overview
Yellow fever is an acute viral disease.[1] It is an important cause of hemorrhagic illness in many African and South American countries despite existence of an effective vaccine. The yellow refers to the jaundice symptoms that affect some patients.[2] Yellow fever has been a source of several devastating epidemics. French soldiers were attacked by yellow fever during the 1802 Haitian Revolution; more than half of the army perished due to the disease.[3] Outbreaks followed by thousands of deaths occurred periodically in other Western Hemisphere locations until research, which included human volunteers (some of whom died), led to an understanding of the method of transmission to humans (primarily by mosquitos) and development of a vaccine and other preventative efforts in the early 20th century. Despite the costly and sacrificial breakthrough research by Cuban physician Carlos Finlay, American physician Walter Reed, and many others over 100 years ago, unvaccinated populations in many developing nations in Africa and Central and South America continue to be at risk.[4] As of 2001, the World Health Organization (WHO) estimates that yellow fever causes 200,000 illnesses and 30,000 deaths every year in unvaccinated populations.[5]
Historical Perspective
Yellow fever has had an important role in the history of Africa, the Americas, Europe, and the Caribbean. Scientists believe that yellow fever evolved in Africa around 3,000 years ago. [6] In 1937 Max Theiler working at the Rockefeller Foundation developed a vaccine for yellow fever that gives a ten-year or more immunity from the disease and effectively protects people traveling to affected areas, while at the same time being a means to control the disease.
Pathophysiology
Yellow fever is caused by a single-stranded RNA virus that belongs to the genus Flavivirus. Vectorborne transmission occurs via the bite of an infected mosquito, primarily Aedes or Haemagogusspp. Nonhuman and human primates are the main reservoirs of the virus, with anthroponotic (human-to-vector-to-human) transmission occurring. Humans infected with YFV experience the highest levels of viremia and can transmit the virus to mosquitoes shortly before onset of fever and for the first 3–5 days of illness. Given the high level of viremia, bloodborne transmission theoretically can occur via transfusion or needlesticks.
Causes
Yellow fever virus is caused by an arthropodborne virus of the Flaviviridae family in the genus Flavivirus. Flaviviruses are single stranded ribonucleic acid (RNA) viruses that replicate in the cytoplasm of infected cells. Seven genotypes of yellow fever virus have been identified, two in South America and five in Africa.
Differentiating Yellow Fever from other Diseases
Yellow fever must be differentiated from other diseases that cause fever, diarrhea, dehydration and tachycardia, such as ebola, typhoid fever, malaria and lassa fever.
Epidemiology and Demographics
Yellow fever occurs in sub-Saharan Africa and tropical South America, where it is endemic and intermittently epidemic. Urban yellow fever occurs periodically in Africa and sporadically in the Americas. In Africa, natural immunity accumulates with age, and thus, infants and children are at highest risk for disease. In South America, yellow fever occurs most frequently in unimmunized young men who are exposed to mosquito vectors through their work in forested areas.
Risk Factors
Screening
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Primary Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
References
- ↑ Schmaljohn AL, McClain D. (1996). Alphaviruses (Togaviridae) and Flaviviruses (Flaviviridae). In: Baron's Medical Microbiology (Baron S et al, eds.) (4th ed. ed.). Univ of Texas Medical Branch. ISBN 0-9631172-1-1.
- ↑ Anker M, Schaaf D; et al. (2000-01-07). "WHO Report on Global Surveillance of Epidemic-prone Infectious Diseases" (PDF). WHO. p. 11. Retrieved 2007-06-11.
- ↑ Bollet, AJ (2004). Plagues and Poxes: The Impact of Human History on Epidemic Disease. Demos Medical Publishing. pp. pp. 48&ndash, 9. ISBN 188879979X.
- ↑ Tomori O (2002). "Yellow fever in Africa: public health impact and prospects for control in the 21st century". Biomedica. 22 (2): 178–210. PMID 12152484.
- ↑ "Yellow fever fact sheet". WHO—Yellow fever. Retrieved 2006-04-18.
- ↑ "Centers for Disease Control and Prevention (CDC). Yellow Fever: History, Epidemiology and Vaccination Information. (Internet). Atlanta, GA: US Department of Health and Human Services, CDC; 2010".