Little Bits of History

Yellow Fever

Posted in History by patriciahysell on April 28, 2015
Yellow Fever Virus

Yellow Fever Virus

April 28, 1932: Drs. Wilbur A. Sawyer, Wray D.M. Lloyd, and Stuart F. Kitchen announce a new vaccine. The public announcement was made at a meeting of the American Societies for Experimental Biology held in Philadelphia, Pennsylvania. Their research was sponsored by the Rockefeller Foundation. Their vaccine was for yellow fever. It is an acute viral disease and presents as fever, chills, loss of appetite, nausea, muscle pains (especially in the back), and headaches. Symptoms usually improve after about five days. Unfortunately, with some cases, after initial improvement, the patient presents again with abdominal pain and liver damage can cause the skin to turn yellow (jaundice). If this happens, there is also a risk of bleeding and kidney damage.

The disease is spread by the bite of the female mosquito. Only humans, other primates, and several species of mosquitoes can be infected. Yellow fever causes 200,000 infections yearly with about 30,000 deaths. Cases are found primarily in Africa. Other tropical regions can be affected as well in South America. It is not found in Asia. With an effective vaccine against the disease, it is often required for travelers visiting areas at risk obtain the vaccine. Today, the vaccine uses a live but attenuated strain of the yellow fever virus called 17D. The mechanism of the attenuation and immunogenicity for the strain remains unknown, but the vaccine is safe with few side effects.

The current vaccine was created by Max Theiler who also worked at the Rockefeller Foundation. The vaccine offers immunity to more than 90% of patients after the first dose. Protection begins ten days after vaccination so travel plans need to be made accordingly. At least 95% of those vaccinated remain immune for ten years with about 81% still immune after 30 years. For those living in the affected regions of the globe, the World Health Organization recommends routine vaccinations between the ninth and twelfth months after birth. In rare cases (less than 1 in 200,000 – 300,000), the vaccine can cause yellow fever vaccine-associated viscerotropic disease which has a 60% fatality rate.

While the vaccine is very helpful, the other course of action possible is vector control – getting rid of the mosquitoes. Aedes aegypti is the mosquito in question and controlling it not only helps with yellow fever, as it can also carry dengue fever and chikungunya disease. The mosquitos breed in stagnant water or domestic waste, both common in urban areas in the developing world. There are two approaches to getting rid of the mosquitoes. One is to kill the larvae by reducing pooled water areas and using larvicides. The other is to reduce the numbers of adult mosquitoes using pesticides. If nothing works and a patient gets yellow fever, there is no cure. Viral agents have been ineffective and palliative treatment is all that remains available.

I have never yet met a healthy person who worried very much about his health, or a really good person who worried much about his own soul. – J. B. S. Haldane

Excellence in health means devoting your life to ending poverty. – Patch Adams

The trouble with always trying to preserve the health of the body is that it is so difficult to do without destroying the health of the mind. – Gilbert Keith Chesterton

My main mistake was to have made an ancient people advance by forced marches toward independence, health, culture, affluence, comfort. – Mohammed Reza Pahlavi

Also on this day: A Voyage to the South Sea – In 1789, the Mutiny on the Bounty takes place.
Kon-Tiki – In 1947, Thor Heyerdahl set sail.
Exposed! – In 1967, Expo 67 opened in Canada.
Scully’s Predecessor – In 1988, Aloha Airline Flight 243 met with disaster.
Men and Their Flying Machines – In 1910, three aviation firsts took place.

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