Scientists recently announced they used genomics to reveal distinct sexual networks for syphilis transmission in England.
On September 15, 2023, The Lancet Microbe published a study by researchers with the UK Health Security Agency and the Wellcome Trust Sanger Institute, which revealed infectious syphilis diagnoses tripled since 2010.
In England, new diagnoses of early syphilis increased from 3,011 in 2012 to 8,011 in 2019.
About 50% of the cases were in the greater London area.
By comparing the bacterial genomes from different individuals, the researchers could identify single-letter changes in the DNA – known as single nucleotide polymorphisms – to distinguish one bacterium strain or sublineage of T. pallidum from another.
They show distinct transmission chains between individuals and significant resistance to a commonly prescribed class of antibiotics in England.
These health officials believe the increase in syphilis cases reflects increased sexually transmitted disease testing and transmission.
Dr. Ana Cehovin, Senior Research Manager of Infectious Disease at Wellcome, commented in a press release, "Genomic surveillance is an invaluable tool for understanding how diseases are spreading, what populations are at increased risk, and which strains are developing drug resistance."
"Similarly, realizing the potential of genomic surveillance to identify and monitor drug resistance can help decision makers to implement necessary mitigation measures to control the spread of resistant strains, reducing the chance of disease escalation and protecting at-risk communities."
Syphilis is a sexually transmitted infection caused by T. pallidum.
While the genomes of T. pallidum are highly conserved compared to other bacterial pathogens - as they tend to transmit more frequently than they mutate - subtle differences can still exist as it spread through a population.
By comparing how genetically related T. pallidum samples are between individuals with a syphilis diagnosis, scientists hope to pinpoint the source of syphilis outbreaks and construct networks that capture its spread.
As of September 18, 2023, there are no approved syphilis vaccines.
Additionally, about 20 mpox patients were confirmed during 2023 in a similar population subset in London. And various poliovirus samples were confirmed in London in 2022.