What is the yellow fever virus?

The virus is passed through the bite of an infected mosquito; it does not spread through ordinary casual contact with another traveller. Illness can begin with fever, headache, muscle aches, nausea, or tiredness. Some people with yellow fever develop more severe features, including jaundice, bleeding, or organ problems. Symptoms after travel do not identify the cause on their own, but travel location and timing help clinicians assess infections that require testing and treatment.

Before travel, check whether your destination has yellow fever risk or vaccination requirements. A travel-health appointment can determine whether vaccination is appropriate and can cover other relevant vaccines. Prevent mosquito bites by using repellent as directed, wearing protective clothing where practical, and choosing accommodation with measures that limit mosquito entry. If you develop symptoms, avoid further mosquito bites while arranging medical advice, because this can reduce opportunities for mosquitoes to pick up infection.

Get urgent medical care for fever after travel to an affected region, particularly if it comes with severe headache, repeated vomiting, marked weakness, yellowing of the skin or eyes, abdominal pain, bleeding, confusion, or breathing difficulty. Tell the clinical team about every destination, dates of travel, mosquito exposure, and vaccination history. Do not wait for a specific symptom pattern to become clear if you are becoming rapidly more unwell.

Ask whether your itinerary creates yellow fever exposure or certificate requirements, how to use insect repellent safely, and which symptoms after travel should prompt same-day assessment. If you were ill while away, ask which tests are needed and what information from your trip matters.