Yellow fever is transmitted by the bite of infected mosquitoes, particularly *Aedes* and *Haemagogus* mosquitoes. These mosquitoes breed in tropical and subtropical areas and can spread the virus to humans and non-human primates. The disease is not directly transmitted from person to person but through the mosquito vector. The disease is most commonly found in areas with poor sanitation and dense populations of mosquitoes.

Diagnosis of yellow fever is based on clinical symptoms and confirmed through laboratory tests. Blood tests can detect the yellow fever virus or the antibodies produced in response to infection. In areas where yellow fever is endemic, diagnosis is often based on symptoms and a history of travel to affected regions. Confirmation of the disease is important for appropriate treatment and control measures.

The most effective way to prevent yellow fever is vaccination. A single dose of the yellow fever vaccine provides lifelong protection against the virus. In addition, individuals traveling to endemic areas should take precautions to avoid mosquito bites, such as using insect repellent, wearing long sleeves and pants, and staying in air-conditioned or well-screened accommodations. Eliminating mosquito breeding sites and using bed nets can also reduce the risk of transmission.

There is no specific antiviral treatment for yellow fever. Supportive care is provided to manage symptoms, including fluids, pain relief, and treatments to address complications such as dehydration, fever, and organ failure. In severe cases, hospitalization may be required for intensive care. The prognosis depends on the severity of the disease, with severe cases often requiring close monitoring and treatment in an intensive care unit (ICU).