The Yellow fever virus is a type of virus belonging to the Flaviviridae family, specifically the Flavivirus genus. It is responsible for causing the disease known as yellow fever, which primarily affects humans and certain primates. Yellow fever is transmitted through the bite of infected female mosquitoes, particularly the Aedes aegypti species, but sometimes other types of mosquitoes as well.
The virus itself is spherical in shape, measuring about 40-50 nanometers in diameter. It contains a single-stranded positive-sense RNA genome, which is approximately 11,000 nucleotides long. The genome encodes for three structural proteins - capsid, envelope, and membrane - as well as seven non-structural proteins involved in viral replication.
Upon entering the human body through the mosquito bite, the Yellow fever virus targets and replicates within certain immune cells, primarily macrophages and dendritic cells. This leads to the release of viral particles into the bloodstream, eventually causing systemic infection. Symptoms of yellow fever can include high fever, headache, muscle and joint pain, nausea, vomiting, and jaundice, which gives the disease its name.
Yellow fever can be deadly, with a significant proportion of infected individuals progressing to severe illness. Treatment primarily focuses on alleviating symptoms and managing complications, as there is no specific antiviral therapy available. Prevention, therefore, is crucial, and vaccination against the Yellow fever virus is recommended for individuals living in or traveling to endemic areas.
