Yellow fever is a viral disease of typically short duration.[3] In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains – particularly in the back – and headaches.[3] Symptoms typically improve within five days.[3] In about 15% of people, within a day of improving the fever comes back, abdominal pain occurs, and liver damage begins causing yellow skin.[3][6] If this occurs, the risk of bleeding and kidney problems is increased.[3]
The disease is caused by yellow fever virus and is spread by the bite of an infected mosquito.[3] It infects only humans, other primates, and several types of mosquitoes.[3] In cities, it is spread primarily by Aedes aegypti, a type of mosquito found throughout the tropics and subtropics.[3] The virus is an RNA virus of the genus Flavivirus.[7] The disease may be difficult to tell apart from other illnesses, especially in the early stages.[3] To confirm a suspected case, blood-sample testing with polymerase chain reaction is required.[4]
A safe and effective vaccine against yellow fever exists, and some countries require vaccinations for travelers.[3] Other efforts to prevent infection include reducing the population of the transmitting mosquitoes.[3] In areas where yellow fever is common, early diagnosis of cases and immunization of large parts of the population are important to prevent outbreaks.[3]Once a person is infected, management is symptomatic; no specific measures are effective against the virus.[3] Death occurs in up to half of those who get severe disease.[3][8]
In 2013, yellow fever resulted in about 127,000 severe infections and 45,000 deaths worldwide,[3] with nearly 90 percent of these occurring in Africa.[4] Nearly a billion people live in an area of the world where the disease is common.[3] It is common in tropical areas of the continents of South America and Africa, but not in Asia.[3][9] Since the 1980s, the number of cases of yellow fever has been increasing.[3][10] This is believed to be due to fewer people being immune, more people living in cities, people moving frequently, and changing climate increasing the habitat for mosquitoes.[3]
The disease originated in Africa and spread to South America in the 17th century with the Spanish and Portuguese importation of enslaved Africans from sub-Saharan Africa.[1] Since the 17th century, several major outbreaks of the disease have occurred in the Americas, Africa, and Europe.[1] In the 18th and 19th centuries, yellow fever was considered one of the most dangerous infectious diseases; numerous epidemics swept through major cities of the US and in other parts of the world.[1]
In 1927, yellow fever virus was the first human virus to be isolated.[7][11]
https://en.wikipedia.org/wiki/Yellow_fever
A COMPARISON OF THE SPIROCHETE OF YELLOW FEVER (LEPTOSPIRA ICTEROIDES NOGUCHI) WITH THE LEPTOSPIRA OF WEIL'S DISEASE
- PMID: 19869411
- PMCID: PMC2131351
- DOI: 10.1084/jem.47.2.255
Free PMC article
https://pubmed.ncbi.nlm.nih.gov/19869411/
Leptospira (Ancient Greek: leptos, 'fine, thin' and Latin: spira, 'coil')[1] is a genus of spirochaete bacteria, including a small number of pathogenic and saprophytic species.[2] Leptospira was first observed in 1907 in kidney tissue slices of a leptospirosisvictim who was described as having died of "yellow fever".[3]
https://en.wikipedia.org/wiki/Leptospira
above.
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