Syphilis Changing Its Genes Is the Reason for the Continuous Spread of the Infection Throughout the Years

It was 1905 when the bacteria, Treponema pallidum, responsible for causing syphilis, was first identified. It took 38 years for an effective treatment to be found, that is, once penicillin was discovered. Since then, syphilis, being of the common sexually transmitted diseases (STDs), has affected people all around the world

In 2016, in the United States alone, there have been more than 88,000 cases of syphilis, as reported by the Centers for Disease Control and Prevention (CDC). On a global level, the estimated number of new syphilis cases each year is around 6 million cases, most of them reported among people between the ages of 15 and 49.

Although we have come a long way since the disease has been first identified, in terms of both treatment and prevention, there is still a continuous spread of this dangerous infection. But the researcher may finally have the answer as to how Treponema pallidum is capable of remaining one step ahead of us over the years.

Treponema pallidum being capable of changing its genes and reinfecting people

Although we have been seeing syphilis infections for many years now, there is still so much that we do not know about this frightening infection. One of the reasons as to why that is is the inability to grow the causing bacteria – Treponema pallidum in laboratory conditions. That, however, changed recently as researchers have been working hard around the clock to get the most information that they can regarding this new opportunity of theirs.

A new study conducted by researchers at the UW Medicine in Seattle, published in Plos journal in April 2020, has shed some light on the topic. In this study, the researchers have been investigating the genomes of the syphilis bacteria that they have gathered from a person who has been infected with this very same bacterium for four times throughout the years. 

The researchers have collected blood samples during two syphilis infections that have occurred at intervals of six years. Between this time period, the individual has been infected two more times, despite having eliminated the infection successfully with the use of penicillin. 

What the researchers wanted to find out was whether there had been any noticeable changes in the genomes of the bacterium between the first and the last infection. Surprisingly enough, the researchers did found changes in one specific gene. This could potentially explain why there has been a repeated infection, although the patient’s body has developed an immune response to the several different strains of the bacteria already.

This gene was identified as the Treponema pallidum K (TprK) repetition gene. This gene was responsible for providing instructions for the synthesis of a protein found on the surface of the bacteria – proteins, which are usually the main target of the sole immune attack.

Because this gene was capable of going through gene transformation, thus creating other variants of itself, a persistent infection, it can potentially lead to the late stage of the syphilis infection. Although more research needs to be done, these are some promising results that let us know more about this dangerous infection that we did years ago. Potentially, researchers could use what they now know to develop a vaccine that will improve the function of the immune system when it comes to detecting the different variates of the so-called TprK gene.