Yellow fever is a potentially fatal viral infection that's transmitted by mosquitoes in tropical regions. It has both an urban cycle and a jungle cycle that relies on monkeys ascarriers. This disease is common in South America and in sub-Saharan Africa. Yellow fever can cause sudden epidemics, with a mortality rate of almost 50 per cent. Although a safe, efficient vaccine hasbeen available for the last 60 years, epidemics still occur, constituting a health risk in tropical regions.
The virus is transmitted among humans by a couple of species of mosquito, including Aedesegyptii, which can also transmit dengue fever. It's an unexplained fact that, despite the presence of the Aedes mosquito in Asia, yellow fever is limited to Africa and South America. In its originaljungle cycle, the mosquito sucks the blood of an infected monkey. The mosquito develops a permanent infection, in which the virus accumulates in its salivary glands. Then the mosquito bites anothermonkey, which then also becomes infected with the virus.
The symotoms that indicate the yellow fever include muscle aches, fever, headache, anorexia, nausea, and vomiting. In many patients there willbe improvement in symptoms and gradual recovery occurring three to four days after the onset of symptoms. The incubation period from infection to developing yellow fever is 3 to 16 days. In moreadvanced stages the Anaemia (lack of red blood cells) develops, as well as liver inflammation, hepatitis and jaundice. The kidneys are also affected and bleeding from the mouth, nose and stomach mayoccur, which leads to blood in vomit and faeces, the majority of patients who experience bleeding die in a short space of time.
This disease is very dangerous because there are no medicines that areeffective against this virus. Serious cases of yellow fever always need hospital treatment. As there are no products that combat the virus itself, the doctor can only treat the symptoms, if there's a...