How is Syphilis Transmitted?

Syphilis is considered to be caused by a bacterial sexually transmitted infection (STI), meaning that direct sexual contract is required to contract the infection. The bacterium responsible for the symptoms experienced is known as Treponema pallidus, which is a small spiral shaped bacterium. In terms of size, the bacterium is only 6-15 micrometres (µm) long and 0.25 (µm) wide making it impossible to see with not only the human eye, but it is also unable to be seen by simply using light microscopy techniques. As a result, scientists examining the bacteria in cases of infection must view its distinctive movement patterns using a technique called dark field microscopy. A dark screen is used in combination with bright light to allow for any organism with reflective capabilities to appear visible when light hits and refracts off its surface.

The bacteria that cause syphilis infections are only able to survive outside of the body momentarily before they are no longer able to transfect due to bacteria death.  For an individual to pass on syphilis, another person must come into direct contact with a lesion on the infected person, containing live samples of the bacteria. The most common situation in which this occurs is during oral or penetrative sex where an individual has a sore or wound on their genitalia which comes into contact with another person thereby spreading the infection. It is not possible to indirectly pass on the infection through an inanimate object such as a door handles, toilet seats, eating utensils, hot tubs, swimming pools, shared clothing, bath tubs and other such objects.  The only exception to this is through the use of unclean sex toys that have previously used by someone infected with syphilis.  Once inside the body, the syphilis bacteria must attach to host cells to allow for it to be pathogenic. This occurs through the actions of a muco polysaccharidease, which is an enzyme that breaks down sugars on the surface of the cells.

Another way in which syphilis can be transmitted is through bodily fluids, such as the blood and saliva. In terms of blood especially, it is very important to be aware of the dangers of syphilis transmission as if an individual suffering from syphilis bleeds the infection may be passed on if blood comes into direct contact with any open wound on your body. All care must be taken in this instance to ensure you do not come into contact with anyone’s blood directly and if this unfortunately occurs, a health professional must be informed immediately as there is also a risk of HIV infection. Blood transfusion are another way in which people used to be infection by syphilis, however the receipt of blood products containing infection has been greatly reduced due legislation put in place that requires a strict screening processes for all donated blood samples, reducing the risk of receiving contaminated blood.

As it is possible to spread syphilis infection via blood, it is also the case that syphilis can be spread by the shared use of unsterilized needles.  Unless sterilized using a professional autoclave devise, needles are likely to still contain any pathogenic bacteria that was present within the blood of the previous user or from the environment. Therefore, it is common to see higher syphilis infection rates in those individuals who are users of intravenously injected recreational drugs, such as heroin, than when compared to the general population.

If a woman is pregnant, she may carry the risk of passing syphilis on to her unborn baby via blood exchange within the placenta, from the maternal circulation to the foetal circulation.  This type of infection is not acquired like all the other types but is instead considered to be congenital syphilis. The passing of the infection may have serious implications for the newborn baby in terms of development so if you believe you may have syphilis and might be pregnant it is vital you get checked and treated straight away.

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