What should you know about the virus that causes yellow fever?

The virus circulates between mosquitoes and susceptible people in certain tropical regions. An infected person does not usually spread it through ordinary casual contact. Early illness may include fever, headache, muscle aches, nausea and marked tiredness. Some people then develop more serious disease affecting the liver or other organs, which can cause jaundice, bleeding or confusion. Symptoms after travel need to be considered in context, including the places visited and mosquito exposure.

Before travelling to an area where yellow fever occurs, ask a travel-health clinician whether [Yellow Fever Vaccination](/treatments/preventive-care-and-vaccination/yellow-fever-vaccination/) is suitable and whether official entry documentation is needed. Reduce mosquito bites with long clothing, an appropriate repellent, screened or air-conditioned accommodation and bed nets where necessary. If fever develops during or after travel, tell the clinician the countries visited and the dates of travel.

Seek urgent medical care for fever after travel to a risk area, especially with yellowing of the eyes or skin, repeated vomiting, bleeding, severe abdominal pain, confusion, unusual sleepiness or breathing difficulty. Do not wait for symptoms to become severe or assume that a recent vaccination rules out every cause of fever. Call ahead when possible so the service can prepare for a travel-related infection assessment.

Ask whether your itinerary requires vaccination, when protection should be arranged, which mosquito precautions fit the destination, and what symptoms after return need urgent review. Bring your travel dates, accommodation details and vaccination record.