What should you know about transmission of yellow fever?

The virus cycles between mosquitoes and susceptible people in regions where yellow fever occurs. A mosquito becomes infected after feeding on an infected host and can transmit the virus when it bites another person. Mosquitoes may bite during the day or night, so exposure is possible beyond sleeping hours. Casual contact, sharing food and drink, coughing and touching do not transmit yellow fever.

Before travel, check whether your destination has yellow-fever transmission and whether entry documentation is required. Discuss vaccination with a travel-health clinician in good time, because suitability depends on your health, age and itinerary. Reduce mosquito bites with long clothing, an appropriate repellent, screened or air-conditioned rooms and bed protection where needed. Seek medical advice if fever develops during or after travel to an affected area.

Get prompt medical advice for fever, headache, muscle aches, nausea or unusual tiredness after possible exposure, and mention your travel history. Urgent care is needed for yellowing of the skin or eyes, bleeding, confusion, severe vomiting or worsening weakness. Do not wait for symptoms to become severe before explaining the destination and dates of travel.

Ask whether vaccination is suitable for your itinerary, when it should be given, which mosquito precautions fit the destination and what symptoms should trigger medical review after returning.