Most travelers to Africa and South America have heard of Yellow Fever, even if only because there are countries within that have mandatory vaccinization requirements. People that live in these “Yellow Fever Zones” (an estimated 508 million in Africa alone) know this disease as a killer. This is also what is happening in Brazil.
ProMED mail, from the International Society of Infectious Disease, recently reported a third case and second fatality from YF since the new year. The latest case involved a 24-year-old man from the region of Goianesa. In 2008, there are 26 suspected cases, three confirmed, and 17 pending results of labwork. Six of the suspected cases have been excluded. Brazil also reported to the World Health Organization (WHO) that monkeys were dying of YF, in December 2007.
The Center for Disease Control (CDC) in Atlanta has also released an outbreak notice and stresses the importance of the vaccine for travelers heading to yellow fever areas.
Immunization is the traditional preventative measure against Yellow Fever, and the in Congonhas airport in Sao Paulo — a major travel hub for the region — 1000 people a day are receiving the free vaccine. Savvy travelers may have heard news of a few vaccine associated deaths recently, in Peru. The vaccines in question were manufactured in Brazil, by Bio-Manguinos. All deaths are still under investigation and believed to be associated with the same lot numbers. The vaccines used in North America are from a seperate manufacturer, Sanofi-pasteur. All vaccines from the batch in question, and several from related lots, have been removed.
The Yellow Fever vaccine is considered relatively safe and effective by the CDC. Administered as a single dose under the skin, the vaccine is a live virus. Contraindications to the vaccine are people who are pregnant, immunocompromised or less than 9 months old. Interestingly, the vaccine is grown in chicken eggs and is also to be avoided by those with egg allergies. WHO advises the vaccine be given routinely to children in endemic areas, around the age of 9 months to one year of age. For travelers who are not candidates for the vaccine, a waiver is possible.
Why do you need the vaccine? Besides the country requirements for entry, the disease can be fatal.
Here is some basic information on the disease:
Basics: An Arbovirus spread via arthropods (mosquitos) in the genus Flavivirus. Symptoms include fever, head and backaches, fatigue and nausea. May progress to hemorrhagic complications and/or liver failure. Jaundice is also common. This is a vaccine preventable disease and proof of vaccinization is often required at customs.
Location: Only in Africa and South America. No reported cases in Asia, although the required mosquito species is present to carry the disease.
Transmission/Incubation: Bites from infected Aedes species mosquitoes in cities or Haemagogus species in jungles. The main vector is Aedes Aegypti in urban areas and an incubation of 3-6 days.
Prevention: Vaccination lasts for 10 years and is a live virus. Contraindicated with egg allergy, immunocompromised, pregnancy or less that 9 months old individuals. Mosquito awareness/ bite prevention is the other key.
Diagnosis: Antibodies to YF through a blood draw.
Treatment: This is a vaccine preventable disease, treatment once infected is supportive.