Syphilis is “back” and is spreading globally, according to a major new study.
British researchers have found that two lineages of the bacteria, T.pallidum, now dominate around the world. They are SS14 and Nicholls.
The findings come from a study of 23 countries, ranging from those with intense surveillance, such as the USA, and countries with limited sampling, including central Asia, Australia and Africa.
They found that in 12 countries both strains of the disease are circulating and that there was very little variation in the organisms in many countries.
This suggests the disease is circulating internationally rather than in local outbreaks, they say.
The work was undertaken by the London School of Hygiene and Tropical Medicine and the Wellcome Sanger Institute, Cambridge.
Incidence of the disease fell last century after the AIDs epidemic led to widespread adoption of safe sexual practices. The researchers say incidence has quadrupled in some countries in the last decade.
The researchers found that many samples were resistant to macrolides but there was no resistance to benzathine benzylpenicillin.
Researcher Dr Matthew Beale, from the Sanger Institute, said: “Our analysis shows a population bottleneck occurred in the late 1990s that indicates a large decline in the population size of T. pallidum, most likely as a result of the HIV/AIDS crisis.
“The concerning thing from a public health perspective is that the presence of almost identical samples in numerous countries suggests the disease is being transmitted internationally on a regular basis. Syphilis is back and it is global.”
Another researcher Dr Helen Fifer, from the UK Health Security Agency, said: “The explosion of syphilis cases in recent decades is hugely concerning. It is a sexually transmitted infection that can easily go undetected, with a large proportion of cases being diagnosed at the latent stage among men who have sex with men (MSM) in recent years. An increase in syphilis among heterosexuals is also concerning due to the risk of congenital syphilis.”
Mathew A. Beale, Michael Marks and Michelle J. Cole et al. Global phylogeny of Treponema pallidum lineages reveals recent expansion and spread of contemporary syphilis. Nature Microbiology 24 November 2021
Leave a Reply