Enteric, Zoonotic and Vector-Borne Diseases
Yellow fever is a vaccine-preventable mosquito-borne, viral infection that is found in the tropical and subtropical areas of Africa and Central and South America. The virus is transmitted by certain species of Aedes mosquitoes, which are currently not established in Canada. All cases of yellow fever reported in Ontario are travel-related. There is no human-to-human transmission of yellow fever.
Most yellow fever infections occur in people who live in regions where yellow fever is common. Most infections show no to mild symptoms including: fever, chills, headache, vomiting and fatigue. Symptoms usually appear within three to six days. Approximately 15 per cent will progress to develop severe symptoms such as: high fever, jaundice, and bleeding, progressing to shock and organ failure. There are no specific medications to treat infections; treatment is supportive. For those that develop severe symptoms, the case fatality ratio is between 20 and 50 per cent.
The yellow fever vaccine is recommended for travellers between the ages of nine months and 60 years going to regions of the world where yellow fever is common. For those outside of this age range and still travelling to yellow fever areas, they should consult with a physician, or travel health clinic. In Canada, the yellow fever vaccine is only available at Public Health Agency of Canada designated vaccination centres. To protect yourself from infection, in addition to vaccine, travellers should try to avoid mosquito bites by wearing insect repellent, long-sleeved clothing, and be aware that the primary mosquito vectors bite during the daytime.