Trading syphilis for malaria: How doctors treated one deadly disease by infecting patients with another
Sarah Watts is a health and science writer based in Chicago. Follow her on Twitter at @swattswrites.

In the 1920s, doctors induced a high fever in patients - so called "fever therapy" - as a way to help them recover from syphilis, though it involved ethical problems.
If you had lived one hundred years ago, syphilis – a bacterial infection spread by sexual contact – would likely have been one of your worst nightmares. Even though syphilis still exists, it can now be detected early and cured quickly with a course of antibiotics. Back then, however, before antibiotics and without an easy way to detect the disease, syphilis was very often a death sentence.
To understand how feared syphilis once was, it’s important to understand exactly what it does if it’s allowed to progress: the infections start off as small, painless sores or even a single sore near the vagina, penis, anus, or mouth. The sores disappear around three to six weeks after the initial infection – but untreated, syphilis moves into a secondary stage, often presenting as a mild rash in various areas of the body (such as the palms of a person’s hands) or through other minor symptoms. The disease progresses from there, often quietly and without noticeable symptoms, sometimes for decades before it reaches its final stages, where it can cause blindness, organ damage, and even dementia. Research indicates, in fact, that as much as 10 percent of psychiatric admissions in the early 20th century were due to dementia caused by syphilis, also known as neurosyphilis.
Like any bacterial disease, syphilis can affect kids, too. Though it’s spread primarily through sexual contact, it can also be transmitted from mother to child during birth, causing lifelong disability.
The poet-physician Aldabert Bettman, who wrote fictionalized poems based on his experiences as a doctor in the 1930s, described the effect syphilis could have on an infant in his poem Daniel Healy:
I always got away clean
when I went out
With the boys.
The night before
I was married
I went out,—But was not so fortunate;
And I infected
My bride.
When little Daniel
Was born
His eyes discharged;
And I dared not tell
That because
I had seen too much
Little Daniel sees not at all
Given the horrors of untreated syphilis, it’s maybe not surprising that people would go to extremes to try and treat it. One of the earliest remedies for syphilis, dating back to 15th century Naples, was using mercury – either rubbing it on the skin where blisters appeared, or breathing it in as a vapor. (Not surprisingly, many people who underwent this type of “treatment” died of mercury poisoning.)
Other primitive treatments included using tinctures made of a flowering plant called guaiacum, as well as inducing “sweat baths” to eliminate the syphilitic toxins. In 1910, an arsenic-based drug called Salvarsan hit the market and was hailed as a “magic bullet” for its ability to target and destroy the syphilis-causing bacteria without harming the patient. However, while Salvarsan was effective in treating early-stage syphilis, it was largely ineffective by the time the infection progressed beyond the second stage. Tens of thousands of people each year continued to die of syphilis or were otherwise shipped off to psychiatric wards due to neurosyphilis.
It was in one of these psychiatric units in the early 20th century that Dr. Julius Wagner-Juaregg got the idea for a potential cure.
Wagner-Juaregg was an Austrian-born physician trained in “experimental pathology” at the University of Vienna. Wagner-Juaregg started his medical career conducting lab experiments on animals and then moved on to work at different psychiatric clinics in Vienna, despite having no training in psychiatry or neurology.
Wagner-Juaregg’s work was controversial to say the least. At the time, medicine – particularly psychiatric medicine – did not have anywhere near the same rigorous ethical standards that doctors, researchers, and other scientists are bound to today. Wagner-Juaregg would devise wild theories about the cause of their psychiatric ailments and then perform experimental procedures in an attempt to cure them. (As just one example, Wagner-Juaregg would sterilize his adolescent male patients, thinking “excessive masturbation” was the cause of their schizophrenia.)
But sometimes these wild theories paid off. In 1883, during his residency, Wagner-Juaregg noted that a female patient with mental illness who had contracted a skin infection and suffered a high fever experienced a sudden (and seemingly miraculous) remission from her psychosis symptoms after the fever had cleared. Wagner-Juaregg theorized that inducing a high fever in his patients with neurosyphilis could help them recover as well.
Eventually, Wagner-Juaregg was able to put his theory to the test. Around 1890, Wagner-Juaregg got his hands on something called tuberculin, a therapeutic treatment created by the German microbiologist Robert Koch in order to cure tuberculosis. Tuberculin would later turn out to be completely ineffective for treating tuberculosis, often creating severe immune responses in patients – but for a short time, Wagner-Juaregg had some success in using tuberculin to help his dementia patients. Giving his patients tuberculin resulted in a high fever – and after completing the treatment, Wagner-Jauregg reported that his patient’s dementia was completely halted. The success was short-lived, however: Wagner-Juaregg eventually had to discontinue tuberculin as a treatment, as it began to be considered too toxic.
By 1917, Wagner-Juaregg’s theory about syphilis and fevers was becoming more credible – and one day a new opportunity presented itself when a wounded soldier, stricken with malaria and a related fever, was accidentally admitted to his psychiatric unit.
When his findings were published in 1918, Wagner-Juaregg’s so-called “fever therapy” swept the globe.
What Wagner-Juaregg did next was ethically deplorable by any standard: Before he allowed the soldier any quinine (the standard treatment for malaria at the time), Wagner-Juaregg took a small sample of the soldier’s blood and inoculated three syphilis patients with the sample, rubbing the blood on their open syphilitic blisters.
It’s unclear how well the malaria treatment worked for those three specific patients – but Wagner-Juaregg’s records show that in the span of one year, he inoculated a total of nine patients with malaria, for the sole purpose of inducing fevers, and six of them made a full recovery. Wagner-Juaregg’s treatment was so successful, in fact, that one of his inoculated patients, an actor who was unable to work due to his dementia, was eventually able to find work again and return to the stage. Two additional patients – a military officer and a clerk – recovered from their once-terminal illnesses and returned to their former careers as well.
When his findings were published in 1918, Wagner-Juaregg’s so-called “fever therapy” swept the globe. The treatment was hailed as a breakthrough – but it still had risks. Malaria itself had a mortality rate of about 15 percent at the time. Many people considered that to be a gamble worth taking, compared to dying a painful, protracted death from syphilis.
Malaria could also be effectively treated much of the time with quinine, whereas other fever-causing illnesses were not so easily treated. Triggering a fever by way of malaria specifically, therefore, became the standard of care.
Tens of thousands of people with syphilitic dementia would go on to be treated with fever therapy until the early 1940s, when a combination of Salvarsan and penicillin caused syphilis infections to decline. Eventually, neurosyphilis became rare, and then nearly unheard of.
Despite his contributions to medicine, it’s important to note that Wagner-Juaregg was most definitely not a person to idolize. In fact, he was an outspoken anti-Semite and proponent of eugenics, arguing that Jews were more prone to mental illness and that people who were mentally ill should be forcibly sterilized. (Wagner-Juaregg later became a Nazi sympathizer during Hitler’s rise to power even though, bizarrely, his first wife was Jewish.) Another problematic issue was that his fever therapy involved experimental treatments on many who, due to their cognitive issues, could not give informed consent.
Lack of consent was also a fundamental problem with the syphilis study at Tuskegee, appalling research that began just 14 years after Wagner-Juaregg published his “fever therapy” findings.
Still, despite his outrageous views, Wagner-Juaregg was awarded the Nobel Prize in Medicine or Physiology in 1927 – and despite some egregious human rights abuses, the miraculous “fever therapy” was partly responsible for taming one of the deadliest plagues in human history.
Sarah Watts is a health and science writer based in Chicago. Follow her on Twitter at @swattswrites.
Following the Footsteps of a 105-Year-Old Sprinter
No human has run a distance of 100 meters faster than Usain Bolt’s lightning streak in 2009. He set this record at age 22. But what will Bolt’s time be when he’s 105?
At the Louisiana Senior Games in November 2021, 105-year-old Julia Hawkins of Baton Rouge became the oldest woman to run 100 meters in an official competition, qualifying her for this year's National Senior Games. Perhaps not surprisingly, she was the only competitor in the race for people 105 and older. In this Leaps.org video, I interview Hawkins about her lifestyle habits over the decades. Then I ask Steven Austad, a pioneer in studying the mechanisms of aging, for his scientific insights into how those aspiring to become super-agers might follow in Hawkins' remarkable footsteps.
Following the Footsteps of a 105-Year-Old Sprinter
No human has run a distance of 100 meters faster than Usain Bolt’s lightning streak in 2009. He set this record at age 22. But what will Bolt’s time be when ...Matt Fuchs is the editor-in-chief of Leaps.org. He is also a contributing reporter to the Washington Post and has written for the New York Times, Time Magazine, WIRED and the Washington Post Magazine, among other outlets. Follow him on Twitter @fuchswriter.
Monkeypox produces more telltale signs than COVID-19. Scientists think that a “ring” vaccination strategy can be used when these signs appear to help with squelching the current outbreak of this disease.
A new virus has emerged and stoked fears of another pandemic: monkeypox. Since May 2022, it has been detected in 29 U.S. states, the District of Columbia, and Puerto Rico among international travelers and their close contacts. On a worldwide scale, as of June 30, there have been 5,323 cases in 52 countries.
The good news: An existing vaccine can go a long way toward preventing a catastrophic outbreak. Because monkeypox is a close relative of smallpox, the same vaccine can be used—and it is about 85 percent effective against the virus, according to the World Health Organization (WHO).
Also on the plus side, monkeypox is less contagious with milder illness than smallpox and, compared to COVID-19, produces more telltale signs. Scientists think that a “ring” vaccination strategy can be used when these signs appear to help with squelching this alarming outbreak.
How it’s transmitted
Monkeypox spreads between people primarily through direct contact with infectious sores, scabs, or bodily fluids. People also can catch it through respiratory secretions during prolonged, face-to-face contact, according to the Centers for Disease Control and Prevention (CDC).
As of June 30, there have been 396 documented monkeypox cases in the U.S., and the CDC has activated its Emergency Operations Center to mobilize additional personnel and resources. The U.S. Department of Health and Human Services is aiming to boost testing capacity and accessibility. No Americans have died from monkeypox during this outbreak but, during the COVID-19 pandemic (February 2020 to date), Africa has documented 12,141 cases and 363 deaths from monkeypox.
Ring vaccination proved effective in curbing the smallpox and Ebola outbreaks. As the monkeypox threat continues to loom, scientists view this as the best vaccine approach.
A person infected with monkeypox typically has symptoms—for instance, fever and chills—in a contagious state, so knowing when to avoid close contact with others makes it easier to curtail than COVID-19.
Advantages of ring vaccination
For this reason, it’s feasible to vaccinate a “ring” of people around the infected individual rather than inoculating large swaths of the population. Ring vaccination proved effective in curbing the smallpox and Ebola outbreaks. As the monkeypox threat continues to loom, scientists view this as the best vaccine approach.
With many infections, “it normally would make sense to everyone to vaccinate more widely,” says Wesley C. Van Voorhis, a professor and director of the Center for Emerging and Re-emerging Infectious Diseases at the University of Washington School of Medicine in Seattle. However, “in this case, ring vaccination may be sufficient to contain the outbreak and also minimize the rare, but potentially serious side effects of the smallpox/monkeypox vaccine.”
There are two licensed smallpox vaccines in the United States: ACAM2000 (live Vaccina virus) and JYNNEOS (live virus non-replicating). The ACAM 2000, Van Voorhis says, is the old smallpox vaccine that, in rare instances, could spread diffusely within the body and cause heart problems, as well as severe rash in people with eczema or serious infection in immunocompromised patients.
To prevent organ damage, the current recommendation would be to use the JYNNEOS vaccine, says Phyllis Kanki, a professor of health sciences in the division of immunology and infectious diseases at the Harvard T.H. Chan School of Public Health. However, according to a report on the CDC’s website, people with immunocompromising conditions could have a higher risk of getting a severe case of monkeypox, despite being vaccinated, and “might be less likely to mount an effective response after any vaccination, including after JYNNEOS.”
In the late 1960s, the ring vaccination strategy became part of the WHO’s mission to globally eradicate smallpox, with the last known natural case described in Somalia in 1977. Ring vaccination can also refer to how a clinical trial is designed, as was the case in 2015, when this approach was used for researching the benefits of an investigational Ebola vaccine in Guinea, Kanki says.
“Since Monkeypox spreads by close contact and we have an effective vaccine, vaccinating high-risk individuals and their contacts may be a good strategy to limit transmission,” she says, adding that privacy is an important ethical principle that comes into play, as people with monkeypox would need to disclose their close contacts so that they could benefit from ring vaccination.
Rapid identification of cases and contacts—along with their cooperation—is essential for ring vaccination to be effective. Although mass vaccination also may work, the risk of infection to most of the population remains low while supply of the JYNNEOS vaccine is limited, says Stanley Deresinski, a clinical professor of medicine in the Infectious Disease Clinic at Stanford University School of Medicine.
Other strategies for preventing transmission
Ideally, the vaccine should be administered within four days of an exposure, but it’s recommended for up to 14 days. The WHO also advocates more widespread vaccination campaigns in the population segment with the most cases so far: men who engage in sex with other men.
The virus appears to be spreading in sexual networks, which differs from what was seen in previously reported outbreaks of monkeypox (outside of Africa), where risk was associated with travel to central or west Africa or various types of contact with individuals or animals from those locales. There is no evidence of transmission by food, but contaminated articles in the environment such as bedding are potential sources of the virus, Deresinski says.
Severe cases of monkeypox can occur, but “transmission of the virus requires close contact,” he says. “There is no evidence of aerosol transmission, as occurs with SARS-CoV-2, although it must be remembered that the smallpox virus, a close relative of monkeypox, was transmitted by aerosol.”
Deresinski points to the fact that in 2003, monkeypox was introduced into the U.S. through imports from Ghana of infected small mammals, such as Gambian giant rats, as pets. They infected prairie dogs, which also were sold as pets and, ultimately, this resulted in 37 confirmed transmissions to humans and 10 probable cases. A CDC investigation identified no cases of human-to-human transmission. Then, in 2021, a traveler flew from Nigeria to Dallas through Atlanta, developing skin lesions several days after arrival. Another CDC investigation yielded 223 contacts, although 85 percent were deemed to be at only minimal risk and the remainder at intermediate risk. No new cases were identified.
How much should we be worried
But how serious of a threat is monkeypox this time around? “Right now, the risk to the general public is very low,” says Scott Roberts, an assistant professor and associate medical director of infection prevention at Yale School of Medicine. “Monkeypox is spread through direct contact with infected skin lesions or through close contact for a prolonged period of time with an infected person. It is much less transmissible than COVID-19.”
The monkeypox incubation period—the time from infection until the onset of symptoms—is typically seven to 14 days but can range from five to 21 days, compared with only three days for the Omicron variant of COVID-19. With such a long incubation, there is a larger window to conduct contact tracing and vaccinate people before symptoms appear, which can prevent infection or lessen the severity.
But symptoms may present atypically or recognition may be delayed. “Ring vaccination works best with 100 percent adherence, and in the absence of a mandate, this is not achievable,” Roberts says.
At the outset of infection, symptoms include fever, chills, and fatigue. Several days later, a rash becomes noticeable, usually beginning on the face and spreading to other parts of the body, he says. The rash starts as flat lesions that raise and develop fluid, similar to manifestations of chickenpox. Once the rash scabs and falls off, a person is no longer contagious.
“It's an uncomfortable infection,” says Van Voorhis, the University of Washington School of Medicine professor. There may be swollen lymph nodes. Sores and rash are often limited to the genitals and areas around the mouth or rectum, suggesting intimate contact as the source of spread.
Symptoms of monkeypox usually last from two to four weeks. The WHO estimated that fatalities range from 3 to 6 percent. Although it’s believed to infect various animal species, including rodents and monkeys in west and central Africa, “the animal reservoir for the virus is unknown,” says Kanki, the Harvard T.H. Chan School of Public Health professor.
Too often, viruses originate in parts of the world that are too poor to grapple with them and may lack the resources to invest in vaccines and treatments. “This disease is endemic in central and west Africa, and it has basically been ignored until it jumped to the north and infected Europeans, Americans, and Canadians,” Van Voorhis says. “We have to do a better job in health care and prevention all over the world. This is the kind of thing that comes back to bite us.”