A mummified ancestor of Boris Johnson didn’t die of syphilis, shocked scientists have revealed — and the true culprit is something we’ve never seen before.
The corpse, branded “Switzerland’s most famous mummy,” made headlines in 2018 when it was identified as Anna Catharina Bischoff, Johnson’s sixth great-grandmother.
Her remains, found in 1975, contained high levels of mercury — historically a treatment for syphilis — so the disease was believed to have killed her.
But now an analysis of the microbes in her mummified organs has revealed not syphilis, but high levels of a bacteria previously unknown to science.
Microbiologist Mohamed Sarhan of Eurac Research said: ‘The initial assumption was based on the presence of mercury in her body, especially in the lungs.
A mummified ancestor of Boris Johnson didn’t die of syphilis, shocked scientists have revealed – and the true culprit is something we’ve never seen before
‘This could indicate an inhaled treatment for syphilis, as this was the protocol followed at the time.
“So we analyzed many samples from every organ in her body to see if we could find DNA traces of the syphilis-causing pathogen, but we couldn’t.
“Instead, we found this new bacteria that was very abundant in the brain tissues and correlated with the highest concentration of mercury in the brain.”
Comparing the mysterious ancient bacteria with today’s bacteria revealed something intriguing.
It contained similar sets of genes to those found in modern bacteria that cause bone lesions and lung symptoms.
Bone lesions, which are visible in Bischoff’s remains, are a known symptom of untreated late-stage syphilis.
So she may have been misdiagnosed with the sexually transmitted infection when the true cause of her illness was something unknown.
For Dr. Sarhan, it is enough to rule out syphilis as the cause of death.
He said: ‘The assumption that she may have died of syphilis can be ruled out, even if she had it.
“Advanced syphilis has very obvious signs that she didn’t have.
‘Moreover, she died at the age of 69, so not very young.
“She also had other health problems, for example: she was overweight and had gallstones, and other problems that are currently being investigated.
“The mercury treatment may have weakened her body and immune system over time, but it wasn’t really the main cause of her death.”
However, Dr. Sarhan’s conclusions are not without controversy.
Her remains, found in 1975, contained high levels of mercury — historically a treatment for syphilis — so the disease was believed to have killed her
An analysis of the microbes in her mummified organs has revealed not syphilis, but high levels of a bacteria previously unknown to science
Gerhard Hotz of the Natural History Museum of Basel, where the mummy is now kept, said: ‘This is where we differ.
‘In the late stages of syphilis you don’t find many bacteria in the body. So it was very difficult to find the old genome of the bacteria.
“So it’s not proof she didn’t have it — for me personally, I still think she had it.” Her skull clearly shows signs of syphilis. But we can’t prove it with genomes.’
Be that as it may, in her day it was certainly believed that Bischoff’s disease was syphilis.
And for a priest’s wealthy widow, that was a devastating diagnosis.
Dr. Hotz said, “Nobody wanted to talk about it. Normally, when people died of her social class from Basel, there was a written obituary about the person, who she was, and so on.
“We found it about everyone, but not her. So we think she died, and she was buried very quickly and privately in the church.”
He said her diagnosis would have prevented her from using public baths or even being treated in a normal hospital.
But it did not necessarily indicate illicit sexual activity.
Dr. Hotz said the scrutiny of the church community would have made an affair difficult to hide, and letters from her husband describing his own illnesses show no symptoms of syphilis.
Comparing the mysterious ancient bacteria with today’s bacteria revealed something intriguing. It contained similar sets of genes to those found in modern bacteria that cause bone lesions and lung symptoms
She may have been misdiagnosed with the sexually transmitted disease when the true cause of her illness was something unknown
Bischoff was born into a wealthy family in Strasbourg, France, in 1719. Her father, a priest himself, served the Swiss families of the city, but when he died at the age of 40, the rest of the family rejoined their relations in Basel.
He continued, “We don’t think it was an affair either her husband’s or herself.
“But there is another explanation: because she was a priest’s wife, she had to visit sick people to comfort them.
“And in Strasbourg, near where she lived, there was a hospital for syphilis, so we think she went there to visit sick people.
“And if someone is newly infected, you can easily become infected.”
Bischoff was born into a wealthy family in Strasbourg, France, in 1719.
Her father, himself a priest, served the Swiss families of the city, but when he died at the age of 40, the rest of the family rejoined their family in Basel.
Bischoff’s husband would eventually take over her father’s old job in Strasbourg, and she lived there for over 40 years and had seven children, four of whom lived to adulthood.
Her eldest daughter, also called Anna Katharina, is Boris Johnson’s fifth great-grandmother.
After her husband’s death, Bischoff returned once more to Basel, where she died in 1787.
And when she was buried in Barfüsser Church, the mercury used to treat her slowed her putrefaction and turned her into a mummy.
HOW ARE BODY MUMMIFIED NATURALLY?
Tollund Man (pictured), who lived in the fourth century BC, is one of the best studied examples of a ‘bog body’
Natural mummification is defined as the process of preserving the skin and organs of a deceased person or animal, without the addition of chemicals by humans.
It is rare and only happens in specific situations.
These include: extreme cold, dry conditions or a lack of oxygen.
Naturally preserved mummies have been found in deserts, buried in low-oxygen peat bogs, and frozen in glaciers.
Some ancient societies accidentally encouraged this process, as they would paint the bodies and cover the face of the deceased with a mask.
This created an impermeable layer through which the process could take place.
All over the UK, bogs provide the perfect environment for this to happen.
Discovered in Denmark in 1950, Tollund Man is one of the best studied examples of a bog body.
The man, who lived in the fourth century BC, was so well preserved that he was initially mistaken for a recent murder victim.
