Yellow Fever Outbreak in Brazil Draws Concern From U.S. Health Officials




yellow fever outbreak in Brazil could spread to the U.S., according to a recent article in The Washington Post. Health officials fear the fast moving virus could increase as rapidly as the Zika virus — both transmitted by the same Aedes aegypti mosquito.


March updates from the Pan American Health Organization state that since December 2016 there have been more than 1,500 reported cases of yellow fever in Brazil with a death rate of 34% among confirmed cases. Brazilian officials are now stepping up vaccination campaigns and warning travelers away.


What Is Yellow Fever?


Yellow fever is an acute viral hemorrhagic disease, and, like Zika, it is transmitted to humans by infected Aedes aegypti mosquitoes. Yellow fever occurs in tropical and subtropical areas of Africa and the Americas. The “yellow” in the name refers to the jaundice that affects some patients. (Jaundice causes the skin and other body tissues to turn yellow.) The illness can range in severity from a fever to severe liver disease with bleeding. About 15% of people who get yellow fever become ill enough to experience bleeding, shock, organ failure and sometimes death.

There is an effective vaccine for yellow fever, but it is a disease that is often forgotten and not vaccinated against routinely, especially in urban areas. In isolated and underserved areas like the Brazilian jungles, few people are vaccinated against the illness, much less diagnosed and treated. The Centers for Disease Control and Prevention reports a current shortage of yellow fever vaccine, which could lead to more cases of the disease.


WiRED International recently issued a medical and health education module on yellow fever. The module includes the infection’s description, its means of transmission, signs and symptoms, diagnosis, laboratory evaluation and treatment, as well as technical guidelines for health professionals. As always, WiRED stresses prevention, which, in this case, includes vaccination, wearing protective clothing, using insect repellent and mosquito vector control.


The key to containing any outbreak is for health professionals and general populations to be prepared and educated about disease health risks and prevention.





The History of Yellow Fever


1000 B.C. Scientists believe yellow fever originated in Africa at least 3,000 years ago.
1600s Yellow fever traveled to the western hemisphere on slave ships from West Africa.
1648 Mayan manuscripts provided the first recorded evidence of the disease.
1700s Yellow fever spread from the Americas to Europe.
Late 1800s Scientists realized that the illness was spread by mosquitoes and not by direct contact with infected individuals or contaminated objects.
1898 Ongoing outbreaks prompted the creation of The Reed Yellow Fever Commission, led by American army surgeon Walter Reed. The Commission proved that the Aedes aegypti mosquito transmitted yellow fever to humans.
1906 The building of the Panama Canal had been severely hampered by the yellow fever infection in workers. Stringent sanitation programs stopped the outbreaks and enabled completion of the Panama Canal.
1930 Two vaccines for yellow fever were developed: the French neurotropic vaccine and the 17D vaccine, which is the one used today.
1950s Yellow fever cases started to appear in Africa and the Americas where vaccine coverage had disappeared or been discontinued.
1980s Outbreaks in Africa swelled to 120,000 cases and 24,000 deaths. Vaccine coverage was poor or nonexistent.
2000s Today there are still far too many people, particularly in Africa, who do not receive the vaccine, and vaccine shortages occur. Hundreds of cases of yellow fever from endemic countries in South America and Africa are still reported annually to the World Health Organization, which estimates that unreported cases number in the thousands.


Source: CDC




Sample Quiz from WiRED’s Yellow Fever Module


1. Yellow fever principally affects humans and ____________.


2. Most people improve within ________ after the symptoms of yellow fever first appear.

 2 to 3 days
 3 to 4 days
 1 week
 10 days

3. ______________ can sometimes detect the virus in the early stages of the disease.

 Sputum samples
 Blood tests




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