Yellow Jack flagMost of us don’t think much about yellow fever nowadays. There are still a couple hundred thousand cases, and some 30,000 deaths, each year, but almost none are in the first world. Out of sight, out of mind.

But this indifference is new. Until the beginning of the 20th century, yellow fever ran rampant, and was one of the most dreaded of all diseases. Epidemics of yellow fever in New York, Philadelphia, Memphis, and New Orleans killed tens of thousands. There’s a WHO manuscript [pdf link] on yellow fever that lists these and many more outbreaks – page after page of fine-print dates and deaths.

Those who have not lived between Cancer and Capricorn can well fail to conceive readily the sensation of numb, chill dreariness which steals on all hearts, when the news spreads, from mouth to mouth, that Yellow Jack has once more come. … at last it is admitted on the housetops, as well as whispered in the closet, that the deadliest, most awe-inspiring of the plagues of the equatorial regions has obtained admittance within our borders.

–“Yellow Jack“, in Cornhill Magazine, 18921

As I noted earlier, Carlos Finlay made the original suggestion that yellow fever was a mosquito-borne disease in 1881;2 in English, in 1886. 3 Walter Reed and his team confirmed this in 1900, and the discovery was seized on at once.

Mosquitoes in New Orleans, 1905 Yellow fever cases, New Orleans, 1905
“Shows the Distribution of the Principal Mosquitoes of New Orleans”.
Dark squares represent Stegomyia fasciata, the major carrier of yellow fever
Yellow fever cases in New Orleans, 1905.
“The infected blocks are most numerous in the old, Italian, quarter of the city.”

Yellow fever poster, New Orleans, 1905

(This post was mainly an excuse to post those maps.5  Click for larger versions.)

New outbreaks were checked with enthusiastic mosquito control.

In a few days with very little opposition, sixty to seventy thousand cisterns had been screened in order to prevent the breeding of the Stegomyia fasciata. Mosquito nets became more than ever the rule …

Yellow Fever Prophylaxis in New Orleans, 19055

The virus itself was was isolated in 1927 and the vaccine, made in 1937 by Max Theiler, turned out to be extremely effective; but even before that,  the understanding that mosquitoes were the carriers allowed great strides in reducing the disease.  Not just in the USA, but throughout the Americas:

Havana and Cuba freed from fever by Gorgas, who organized anti-mosquito measures, 1901-1902; example followed in Rio de Janeiro and Vera Cruz, 1903-1909; Panama Canal Zone successfully protected by same methods, 1904-1906 …  intensive campaign, 1918-1919, under Connor eliminated disease from Guayaquil, the chief endemic centre …

–“Yellow Fever in Retreat“, 19226

  1. Cornhill Magazine
    New Series, Vol. XIX, July to December 1892
    Smith, Elder, & Co.
    15 Waterloo Place, London []
  2. C. Finlay (1881). El mosquito hipoteticamente considerado como agente de trasmislon de la flebre amarllla An. de la Real Academia de ciencias med. de la Habana, 18, 147-169[]
  3. C. Finlay (1886). Yellow Fever, its transmission by means of the Culex mosquito Am. Journ. Med. Sci., 92, 395-409[]
  4. If I follow this right — I’m neither an entymologist nor an entomologist — Stegomyia fasciata was subsequently renamed Stegomyia aegypti, then Aedes agyptyi, and now (since 2005) is properly is officially called Stegomyia aegypti once again but usually, if not always, with “Aedes” in brackets to clarify. There was also, maybe, a point at which it was Stegomyia calopus, unless that was something else.[]
  5. Yellow Fever Prophylaxis in New Orleans, 1905
    Rubert Boyce
    April, 1906
    Published for the Committee of the Liverpool School of Tropical Medicine
    by Williams & Norgate
    14 Henrietta Street, Covent Garden, London[][]
  6. Current History
    A Monthly Magazine of the New York Times
    Volume XVI, April-September, 1922[]