Syphilis: New World or Old?

Earlier this month the discovery of a 700 year old skeleton showing signs of congenital syphilis was announced by the Medical University of Vienna. Although this might not sound immediately controversial the skeleton itself comes from St Pölten in Austria and that is unusual because syphilis was thought to have been imported to Europe from America sometime after 1492. In fact the first widely accepted outbreak of the disease in Europe took place amongst the soldiers of Charles VIII in 1495. So how do we explain a case of syphilis in a skeleton dated to 1320 if syphilis comes from the New World?

Syphilis_Bacteria_(16842837731)
Treponema pallidum, the bacteria that causes syphilis. Source: Wikimedia Commons

Syphilis is a severe, sexually transmitted infection that’s caused be a bacteria called Treponema pallidum. It usually progresses through three different phases called primary, secondary and tertiary syphilis which can take years. It produces a wide variety of symptoms from ulcers to neurological damage which led it to be nicknamed ‘the Great Imitator’. If left untreated it can be deadly, eventually, but infection can linger for years, even decades before becoming this serious. This is important because it differs drastically from the first outbreak of the disease in the 1490s. Contemporary accounts describe it as a horrific infection causing large, unsightly pustules and killing its victims far more quickly. We would expect this kind of presentation from a newly introduced disease because it would be spreading through a population with no natural immunity and this strongly hints that syphilis was new to Europe.

This observation, combined with a near-total lack of archaeological evidence for syphilis in Europe or Asia prior to Columbus’s voyage, has led to the prevailing view that syphilis was one of the only disease to ever make the trip across the Atlantic from America to Europe. Almost all other diseases travelled the other way, from smallpox to malaria with devastating results. Somehow it seems intuitive to imagine that at least some pathogens should have come the other way and syphilis seems to fit the bill nicely. However, this new discovery from Austria seems to challenge that assumption. The skeleton itself belonged to a six year old child, gender unknown, found during a dig in the cathedral square of the city of St Pölten. Several other bodies were recovered at the same time but this child was the only to show signs of syphilis. Also the evidence was for a particular type of the disease called congenital syphilis. This means that the child’s mother suffered from the infection too and passed it on to the child in the womb. The evidence for this comes from the child’s teeth.

Skull_damage_from_neurosyphilis
Human skull showing damage from neurosyphilis. Source: Wikimedia Commons

Syphilis is one of the few diseases that does leave marks on the bones and this has led to its identification in several New World skeletons dated to pre-Columbian times. The problem is though that the symptoms of syphilis on the bones can be caused by other diseases so its difficult to draw conclusions from one or two cases. This is the main issue that has dogged previous efforts to identify syphilis in pre-Columbian Eurasian skeletons. However, for congenital syphilis there are some very specific symptoms that are not produced by other diseases, which is why this discovery is so important. The child apparently suffered from something called Hutchinson’s teeth, a specific deformity of the front teeth which leave distinctive ‘grooves’ and is named after the doctor who diagnosed it as a characteristic of congenital syphilis. The child also suffered from a deformity of the back teeth called ‘mulberry molars’ which are similarly of congenital syphilis. These particular deformities are not known to be caused by any other diseases to the researchers who examined the body felt confident in concluding that this child suffered from congenital syphilis.

So how is this possible? Did syphilis exist in Europe all along and then just mutate into a particularly severe form in the 1490s? Well the bacterium Treponema which causes syphilis also has some strains that cause other, related diseases which are found in Europe, Africa and Asia. Perhaps the best known of these is yaws, which affects the skin, bones and cartilage eventually leading to serious damage and deformities if left untreated. It probably originated in Africa before spreading to Europe and later America. So there were disease of the Treponema present in Eurasia and Africa but what about syphilis? The problem is that cases of syphilis from the archaeological record of the Old World are still relatively rare. Its a puzzle, especially in this new case where the evidence seems particularly strong, but it certainly doesn’t seem at the moment as though syphilis was wide spread even if it was present. Also this finding implies that syphilis is an ancient disease since America had almost no contact with the Old World after humans first settled it around 14,000 years ago. It must therefore has existed in the Eurasian or African population prior to this date and was carried to America by those original settlers even as a small reservoir persisted somewhere in the Old World. The other alternative would be that there was some contact before 1492, but apart from the Vikings of Newfoundland there is no evidence of this. For argument’s sake I suppose it’s possible that the Vikings might have first contracted the disease and brought it back with them, but this is pure speculation and not in any way supported by archaeology. Even if we suggested it was possible why were there no severe outbreaks of syphilis until 1495? And then why was there such a severe outbreak in 1495 if the disease was already endemic? Certainly weather condition, poor harvests and other local epidemics can trigger a sudden resurgence of a disease but the severity, odd symptoms and speed of syphilis’ spread certainly seemed to match exactly what we could expect from a pathogen entering a brand new environment.

Its undeniably a puzzle which is why discoveries such as this are so important. By understanding the past spread of diseases we can try to work out how new ones will spread. It also helps us treat those who even today suffer from syphilis. Frankly we still need more evidence if we are to prove where syphilis came from one way or the other and hopefully this finding will pave the way for that evidence.

 

Reference: Gaul, J.S., et al. 2015. A probably case of congenital syphilis from pre-Columbian Austria. Anthropologischer Anzeiger. 72(4). DOI: 10.1127/anthranz/2015/0504

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