sárgalázt

Sárgalázt, Hungarian for yellow fever, is a viral hemorrhagic fever caused by the yellow fever virus, a member of the Flaviviridae family. The disease is transmitted to humans primarily by daytime-biting Aedes mosquitoes, especially Aedes aegypti, in urban settings. There are two main transmission cycles: an urban cycle, in which humans are the main hosts, and a sylvatic (jungle) cycle, in which nonhuman primates serve as reservoirs and mosquitoes transmit the virus among animals and occasionally people.

Incubation is typically 3 to 6 days. The illness often begins with fever, headache, muscle and back pain, nausea, and fatigue. Most patients recover within a week, but a minority enter a toxic phase after a brief remission. The toxic phase is characterized by high fever, jaundice (hence the name), abdominal pain, vomiting, and bleeding, and can lead to organ failure and death. Overall mortality in severe cases can be significant if untreated.

Geographically, yellow fever is endemic in parts of sub-Saharan Africa and tropical South America. Unvaccinated travelers to these areas are at risk, though vaccination and mosquito avoidance substantially reduce risk.

Prevention relies on vaccination with the live-attenuated yellow fever vaccine (17D). A single dose provides long-lasting protection for most people; many countries require proof of vaccination for entry. Complementary measures include mosquito control and personal protection against bites.

There is no specific antiviral treatment for yellow fever; management is supportive care in hospital. Diagnosis is by laboratory tests, typically serology and RT-PCR.

Historical notes: the vaccine was developed by Max Theiler in 1937, for which he received the Nobel Prize in Physiology or Medicine in 1951. See also: Yellow fever, Flavivirus.