Travellers are being cautioned about the reemergence of a disease transmitted by mosquitoes that poses a ‘high risk’ in 42 countries. The Travel Health Pro website, supported by the Foreign Office, has issued a warning regarding the virus spreading in various regions of Africa, Central and South America, as well as Trinidad in the Caribbean.
Yellow Fever is a disease that can lead to a severe hemorrhagic illness with fatal consequences for humans. Health officials emphasize the importance of yellow fever vaccination and taking precautions to avoid mosquito bites as key preventive measures against the disease. The virus can cause symptoms such as jaundice, yellowing of the skin and eyes, and internal bleeding resulting in significant damage to vital organs like the liver, kidneys, and heart, with a high mortality rate in severe cases.
According to Travel Health Pro, yellow fever remains a risk in parts of 13 countries and territories in South and Central America. The region saw a notable increase in cases in 2025, with 346 confirmed human cases, including 143 fatalities reported across seven countries.
Comparatively, there has been a 5.6-fold surge in cases from the previous year. Since the start of 2026, four countries, namely Bolivia, Colombia, Peru, and Venezuela, have reported a total of 41 confirmed cases, including 18 deaths attributed to yellow fever.
In 2024, the majority of yellow fever incidents were recorded in the Amazon region. However, health authorities have noted a shift in the geographic spread of cases, extending beyond the Amazon region to areas like Sao Paulo State in Brazil and Tolima Department in Colombia. Notably, recent reports indicate human cases of yellow fever in Venezuela in regions previously considered low risk for the disease.
The continued risk of yellow fever in African countries is evident through reported probable and confirmed cases. In 2024, countries with inadequate vaccination coverage witnessed confirmed yellow fever cases, including regions with no recent history of disease transmission.
The World Health Organization (WHO) highlights the challenges of under-reporting in some African countries due to surveillance and data collection issues. The risk of yellow fever transmission remains elevated in endemic African areas, where the prevalent Aedes mosquitoes significantly heighten the risk of disease spread, especially in densely populated urban centers, potentially leading to rapid outbreaks.