Transmitted from monkeys to humans by mosquitos, it is a fever characterised by severe fever and headache, often with nausea and nosebleeds. In more serious cases, the fever is higher and there is severe headache and pains in the neck, back and legs. Damage can occur rapidly in liver and kidneys, causing jaundice and kidney failure, which may lead to meningitis, delirium and extreme agitation, leading to coma and death. The yellowing of the skin due to jaundice is where the disease gets its name.
It occurs in Central America, parts of South America, and largely in