Edward McSweegan
Kingston, Rhode Island, United States

The Golden Age of Bacteriology (1876–1906) saw the emergence of techniques to cultivate bacterial pathogens and develop vaccines and anti-toxin therapies against them. The new bacteriologists rapidly identified the agents causing anthrax, gonorrhea, typhoid, tuberculosis, cholera, tetanus, diphtheria, plague, and other infectious diseases.

One microbe that remained stubbornly elusive was that of yellow fever (YF), a deadly, often epidemic disease that threatened the tropics and cities as far north as Boston. Several skilled physician-scientists looked for it, but it was not until June 1897 that Guiseppe Sanarelli at the University of Montevideo in Uruguay announced he had discovered the YF agent. It was a bacterium he called Bacillus icteroides.¹

This news was of interest to George Miller Sternberg, the U.S. Army Surgeon General. Sternberg was known as “America’s Bacteriologist” for his pioneering work in photo-microscopy, his 900-page textbook A Manual of Bacteriology, and his work on YF in Cuba. In 1889, Sternberg tentatively identified a Bacillus X (sometimes called Bacillus cuniculicida havaniensis) as the YF germ. Sternberg had missed earlier chances for professional acclaim for his studies on pneumococcus, immune phagocytosis, and antitoxin neutralization.² Sanarelli appeared to be yet another professional threat. To settle the matter of the two competing bacilli and stake his claim, Sternberg assigned Walter Reed and James Carroll to investigate Sanarelli’s bacillus and its suspected role in YF.

Walter Wyman, Surgeon General of the Marine Hospital Service (MHS), also was interested and sent two MHS physicians—Eugene Wasdin and Henry Geddings—to Cuba to investigate YF with “special reference to the reported discovery of the yellow fever germ by Professor Sanarelli.”³ As head of the MHS (now the Public Health Service), Wyman had tremendous power over public health matters, including the authority to quarantine ships and towns, isolate patients, and fumigate (sometimes burn) cargo and luggage. In November, he raised the status of his two men in Cuba by having them made a special commission approved by the Secretary of the Treasury and appointed by President McKinley.⁴

The outbreak of the Spanish-American War curtailed infectious disease research in Cuba, and Wasdin and Geddings were evacuated in March 1898. But as soon as the shooting stopped, Sternberg sent Aristides Agramonte, an Army Acting Assistant Surgeon, to Cuba to investigate YF outbreaks in the American Army. Agramonte also conducted autopsies looking for Sanarelli’s bacillus in YF cases. He found the bacillus in only three of ten cases and assumed it was a contaminant. That seemed to be the end of Sanarelli’s germ as the cause of YF. But in November 1898, Geddings and Wasdin returned to Cuba and confirmed Sanarelli’s claim based on additional autopsies of suspected YF victims.

In December, Sternberg sent Agramonte back to Cuba. Working for the MHS with the same samples taken at autopsies, Wasdin and Geddings concluded B. icteroides was the cause of YF, but Agramonte working for the Army, denied it.⁵ In Washington, Walter Reed and James Carroll then published their preliminary bacteriological studies of Sanarelli’s bacillus and Sternberg’s bacillus X, concluding the former was the agent of hog cholera and the latter was an atypical colon bacillus.⁶ Ignoring the Army’s conclusions, Wasdin and Geddings issued a July 10 report stating the Sanarelli bacillus caused YF, and there was no “causal relationship between the bacillus X of Sternberg and this highly infectious disease. . . .”⁴ Wyman added to the growing dispute with a July 26 letter to the Treasury Secretary reporting his commission had confirmed the “discovery made by Sanarelli,” and eliminated “incorrect theories,” (a swipe at Sternberg). Wyman also claimed his investigations “must be considered a notable achievement in medical science and one of great practical value.”⁴ Claims and counterclaims between the Army and the MHS, and among Agramonte, Wasdin, and Geddings spilled over into the pages of the journal Medical News, where additional accusations and ad hominin attacks by Sanarelli, Sternberg, Reed, and Carroll were printed for all to read. An editorial in the September 30 issue came down on the side of the MHS: “The recent confirmation of Sanarelli’s claims by the Marine Hospital workers . . . greatly adds to the probability of the etiological relation of the Bacillus icteroides to yellow fever.”⁷

Sternberg was wounded by the published attacks. In response, he established an Army medical board with Walter Reed as its head. Sternberg’s May 23, 1900 written orders to the new board were to pursue investigations of infectious diseases in Cuba “and especially of yellow fever.”⁸ Yet, the next day, the Army’s Adjutant General deleted the order’s reference to YF, worried perhaps about igniting a public dispute with the MHS and its YF commission authorized by the President.⁸ Undeterred, Sternberg gave Reed “verbal instructions” regarding YF. Reed passed those verbal instructions to Agramonte in Cuba in a May 25 personal letter.⁹ Sternberg followed up with a May 29 letter to Reed reiterating the need for “special attention” to studies of YF.¹⁰ When the Army board of Reed, Carroll, Agramonte, and Jesse Lazear first met in Cuba on June 25, Reed provided them with official orders regarding infectious diseases in Cuba, and Sternberg’s verbal instructions about YF.

Cuba now hosted a MHS commission and an Army board, both investigating YF. One was supporting Sanarelli’s bacillus as the cause of YF, the other was determined to show the bacillus was an unrelated contaminant. In the summer of 1900, a YF outbreak near the Army’s Columbia Barracks provided many patients to diagnose and bodies to sample. Reed, the good soldier that he was, devoted so much time to disproving Sanarelli that he wasted “three mosquito-filled summer months” before finally turning to the mosquito-vector theory of Carlos Finlay.¹¹ It is not clear whether Reed believed that mosquitoes transmitted YF, but Sternberg certainly did not. But one man who did believe the mosquito was a likely vector, and who had proof of an intermediate host between human patients, was Henry Rose Carter.

Carter was working in Havana as a quarantine officer. He was an expert on YF, and two years earlier had studied YF outbreaks in Mississippi. From those studies, he found an “extrinsic incubation period” of about two weeks between primary and secondary YF cases. That suggested an intermediate host such as Carlos Finlay’s Aedes aegypti mosquito. Carter told Jesse Lazear as much the same day the Army board first met, and Carter gave him a copy of a manuscript he was planning to publish about the Mississippi outbreaks.

But Carter had a problem; he worked for the MHS. He was advocating a YF etiology that contradicted the conclusions of the MHS Commission. He did not believe that filth or clothing transmitted YF, an opinion that also undermined the MHS’s rationale and budget for quarantining, confiscating, and fumigating. Said an MHS officer named Cobb, “it would be dreadful, after all the years of disinfection” if the mosquito theory proved true.¹² Surgeon General Wyman could not have that happen.

First, Carter’s manuscript on YF in Mississippi was edited to remove three paragraphs about extrinsic incubation and a possible intermediate host. Dr. Henry Geddings was the suspected editor at the MHS, and his rationale for omitting the extrinsic incubation section was that it was theoretical and not factual.¹¹ Then on September 14, Wyman transferred Carter to Kentucky even as he was collaborating with the Army board to propagate and infect mosquitoes with YF. Wyman made a routine practice of transferring troublesome MHS officers.¹³

When Reed returned to Cuba in early October, he found Carter gone, Lazear dead, Agramonte in New York, and Carroll still recovering from YF. Winter was coming and with it would come a decline in human YF cases and viable mosquitoes for research. However, Reed still had Finlay’s mosquitoes, Carter’s manuscript, and Lazear’s personal notebook detailing his human experiments using YF-infected mosquitoes. As the year (and the century) ended, Reed managed to produce YF cases by means of infected mosquito bites. In a final stab at the MHS, he also demonstrated that clothing and bedding from YF patients did not transmit the disease to others.

Not everyone was convinced. Wasdin denounced the Army board’s work at the November meeting of the American Public Health Association in Indianapolis. The Washington Post labeled the mosquito theory “the silliest beyond compare.” The editors of the Philadelphia Medical Journal tried to have it both ways, writing, we see “no reason why the mosquito theory of transmission . . . is incompatible with Sanarelli’s theory. . . .”¹⁴ More convincing proof came with the 1901 campaign in Havana to screen doors and windows, eliminate mosquito breeding areas, and isolate YF patients. During the last decade of the nineteenth century, Havana had averaged 462 annual YF deaths. The last YF death in the city occurred on September 28, 1901.¹⁵

On New Year’s Eve 1900, Reed wrote to his wife about the discovery that YF was transmitted by mosquitos, noting that, “aside from the antitoxin of Diphtheria and Koch’s discovery of the tubercle bacillus, it will be regarded as the most important piece of work, scientifically, during the 19th century.” Yet, it almost was not discovered in the nineteenth century due to personal and institutional interests, and a certain amount of “bacteriomania.”¹⁶ While public health officials now were able to reduce the likelihood of future YF epidemics, the agent of the disease remained mysteriously beyond the reach of the Berkefeld filter and the monochromatic microscope. The YF virus would not be seen until the invention of the electron microscope in 1931.

References

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