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The Columbus Bacterium

Syphilis sailed back to Europe with the voyagers who discovered America – and stayed. With the use of penicillin, "Cupid's disease" started to die out and gradually fell into oblivion. But not for long. Having reappeared at the turn of the millennium, cases have been recorded in Switzerland too.
Michael T. Ganz
Columbus' ship Santa Maria, Paul Schreckhaase, 1904

It's 1493 and Christopher Columbus is returning from his second expedition. It's a punishing journey, and many of the crew are suffering. Spanish physician, Ruy Díaz de Isla, makes notes of their complaints – which will transpire to be the first descriptions of syphilis symptoms: "Terrifying and cruel, it damages the flesh, breaks and destroys the bones, cuts and shrinks the tendons." It took no time for the new disease to manifest itself in a number of port cities along the western Mediterranean and, a year later, when French king Charles VIII marched into Naples with a 30,000-strong army of mercenaries, fate took its course.

Charles' soldiers seized the southern Italian city and celebrated their victory with the local whores — at the time no disreputable way to pass the time. But then the men fell sick and started to waste away. Severely weakened and almost destroyed, the French army moved off, with the mercenaries returning to their home countries. As a result, the disease spread across the whole continent and for half a century a syphilis epidemic raged across the Old World until the pathogen gradually started to lose its virulence and the disease appeared in less dramatic forms. Nonetheless, it remained fatal, as there was no cure.

"Ugly sores"

Scholars are divided as to whether the "Columbus theory" is in fact true. Bone findings in England, Italy and Turkey suggest that syphilis existed in Europe long before the time of Columbus: The oldest syphilitic bones date back to the 6th century BC. Philipp Bosshard, UZH privatdozent with a PhD in microbiology, and lab head at the Department of Dermatology at Zurich University Hospital for the last 11 years, has been studying the origin of the disease. He took part in an international study that proved that the original genome of European syphilis as we know it today is indeed not older than Columbus.

"It's very possible that a kind of syphilis had long existed in Europe," says Bosshard. "However, the data indicates that Columbus and his men imported a new and much more virulent form of the disease from South America." The bacterium very soon reached Switzerland, too. Philipp Bosshard refers to a decree issued by the Zurich Government in 1496 that mentions returning mercenaries "with ugly sores" and instructs people to ban strangers and loose women from the city and to no longer visit bathhouses – for bathhouses were not only used for bathing.

The fact that syphilis is a venereal disease and, on top of this, highly contagious was therefore known at this time, and the uninhibited attitude to sexuality prevalent in Middle Age society turned into fear. Prostitutes, a recognized part of society, were suddenly now despised as carriers of the new disease, and mistrust also nested in marital beds. Condoms – which had existed since antiquity – experienced a revival: Made of linen or silk, however, they hardly offered any protection against infection. "Syphilis drove a wedge between men and women," says Bosshard.

Seeing its chance, the church seized the opportunity to speak of God's punishment and preach chastity, which then led to the disease acquiring its present name: Ruy Díaz de Isla had first called the disease "mal serpentino" after a poisonous snake but, in 1530, Veronese physician Girolamo Fracastoro wrote a poem with the title Syphilis sive morbus Gallicus, in which Apollo punishes the shepherd Syphilius for blasphemy with this very disease. The term "morbus Gallicus," i.e. French disease – used by Fracastoro to allude to the epidemic in Charles VIII's mercenary army – has also survived until the present day.

Baths and sweat lodges

The doctors not only wrote poetry but also frantically searched for a means to heal the sick and contain the epidemic. At the start, they put syphilis patients in baths and sweat lodges. As early as 1497 a doctor from Vicenza recommended the external application of mercury salts – assuming it was a skin disease. Soon, doctors were rubbing patients' bodies all over with mercury ointments, had them inhale mercury vapors, and even gave them mercury to swallow. The cures did indeed stall the course of the sickness. However, even though many patients suffered and died of the effects of heavy metal poisoning, mercury products were used to treat syphilis even into the 20th century.

In 1905, researchers succeeded in detecting the syphilis bacterium with a microscope for the first time. From then on, things progressed very quickly. 1906 saw the introduction of the first detection method – dubbed the "Wassermann test" after its founder – which enabled doctors to deduct the presence of the syphilis pathogen from the antibodies in a patient's blood. And in 1909, German physician and Nobel prize winner Paul Ehrlich developed the chemotherapeutic agent Salvarsan, based on the poison arsenic, which produced successful results but had strong side effects. But it was only with the discovery of the penicillin antibiotic that the 450-year search for an effective medicine reached a happy end. With penicillin, syphilis could – if discovered in time – be fully cured. Fortunately, the syphilis pathogen has not developed any resistance to the miracle drug.

Yet, even today, the problem lies in the "if discovered in time." Firstly, it is difficult to diagnose syphilis with any certainty with the naked eye and, secondly, the bacterium responsible for the disease cannot be detected directly because, in contrast to many other pathogens, it cannot be cultivated in the lab. The stubborn bacterium can only be bred in the testicles of live rabbits. "Doctors used this knowledge for diagnostic purposes in the past," Bosshard explains. "Today, we only do this if larger amounts of the pathogens are required for research purposes."

The only diagnostic method thus remaining is indirect antibody detection, as discovered by August von Wassermann in 1906. However, the Zurich University Hospital has now come up with a new technique: Philipp Bosshard's research team has succeeded in creating a DNA detection method. The new test – which enables those bacteria to be identified that populate the small ulcerations on patients in the primary phase of the disease – works and is ready for application. "The advantage is that it is very fast. After 24 to 48 hours, the proof is there," Bosshard says. "The disadvantage is that this test is more expensive than conventional methods."

Condom fatigue

Bosshard's lab diagnoses two to four new syphilis cases every week. That's more than 10 percent of all cases in Switzerland. Following the discovery of penicillin, the number of cases dropped abruptly, and infections continued to decline as a result of measures preventing the spread of HIV. In the 1970s and 1980s, syphilis was no longer a subject of discussion; the disease had been forgotten. However, since the turn of the millennium, infection rates have risen again, and dramatically so. In 2006, around 600 infections were noted in Switzerland; in 2013 almost double.

Philipp Bosshard sees three reasons for the disease's return. Firstly, people are no longer so scared of HIV. Thanks to the availability of treatments "it's no longer a death sentence," which has created a more relaxed attitude towards sexual intercourse. Known as condom fatigue, this is also evident in the rise in gonorrhea and chlamydia infections, too. Secondly, many people are not aware that syphilis is not only transmitted through vaginal intercourse but also through anal and oral sex, i.e. that protection is required here, too.

And thirdly, Bosshard sees a certain risk in the many new online dating platforms available, particularly apps such as Grindr. Facilitating contact between homosexual and bisexual men, apps such as these can stimulate the spread of sexually transmitted diseases, as also around half of all syphilis infections are found in male homosexuals. So what can people do? "Protect yourself as in the days of AIDS," says Philipp Bosshard. Information campaigns such as the Federal Office of Public Health's "Love Life" campaign as well as regular screens for homosexual HIV patients also help.

Shocking syphilis study

Since 2006 doctors have again been instructed to notify the authorities of every case of syphilis, a ruling that had been lifted after the decline in infection rates. Efforts seem to be bearing fruit: In 2018, the rise of syphilis cases in Switzerland flattened out slightly for the first time. Fewer cases of infection were recorded than in the previous year. However, Philipp Bosshard remains committed to the cause. "There is still room for improvement, especially in diagnostics," the lab head says. "Syphilis is extremely tricky to diagnose. That is what makes my work so interesting."

With a shudder, Bosshard recalls one of the greatest scandals in medicine history involving a study aimed at solving the tricky problem of syphilis diagnosis. From 1932 to 1972 in Tuskegee, a small town in the US state of Alabama, around 400 black and uneducated inhabitants infected with syphilis were consciously not treated in order that doctors could observe the late complications of the disease. The unsuspecting victims of the study were consoled with the diagnosis of "only bad blood." The study continued even after penicillin came onto the market as an effective treatment for syphilis. And it only ended when reports finally leaked out — after no less than 40 years.

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