Can you get syphilis by swimming in a public swimming pool? The truth is...

During the long holidays, many people will arrange activities such as swimming in a swimming pool when traveling. When swimming in a public swimming pool, many people think that the water is too dirty and unhygienic. There was even such a case:

Xiao Zhang went swimming at the weekend and developed a rash after returning home. He went to the hospital for a check-up and the doctor said he needed a blood test, as it might be syphilis. Xiao Zhang was so scared that his back was sweating. How could he get syphilis just from swimming?

How likely is it that you can get syphilis by swimming? Let's talk about this issue today.

First of all, we need to have a clear understanding of syphilis. What is syphilis?

Electron micrograph of Treponema pallidum, source: Wikipedia

Syphilis is a bacterial sexually transmitted disease. The pathogen is a subspecies of the spirochete Treponema pallidum, which was first discovered by Hoffmann and Schauding in Germany in 1905.

Treponema pallidum is also known as Treponema pallidum or Treponema pallidum. Treponema pallidum has a special morphology and diverse antigens. It can invade the human body through damaged skin or mucous membranes or spread through blood and other forms. It can be spread throughout the body through the blood, obtain mucopolysaccharides from host cells, and synthesize N-acetyl-D-galactosamine of the spirochete capsule. After infection, mucopolysaccharides in human cells are decomposed, tissues are damaged, and various syphilis lesions are formed; almost all organs and tissues in the body can be affected, causing complex clinical symptoms.

However, Treponema pallidum infection in humans requires a certain pathogen load and can only occur under certain special conditions.

Secondary syphilis, Image source: Wikipedia

The transmission of syphilis requires two basic elements. One is the carrier of Treponema pallidum . Treponema pallidum mainly survives inside the damaged skin surface of the patient. In addition, Treponema pallidum can also lurk in the patient's mucosa, such as the vaginal mucosa and oral mucosa.

On the other hand, it depends on the infected person. The skin or mucous membrane of the infected person must be damaged . Even if it is an injury that is difficult to detect with the naked eye and feels extremely slight, it can become a portal for the syphilis spirochete to invade the body. In this way, the spirochete of the carrier is transmitted through the damaged skin or mucous membrane of the infected person.

How is syphilis transmitted?

1

Direct sexual contact

95% to 98% of syphilis patients are infected through direct sexual contact. Kissing, homosexuality, and various forms of sexual contact can transmit syphilis, and damage can occur in contact areas such as the lips, anus, tongue, pharynx, and fingers.

However, the life-saving straw we can think of, "condoms", is not completely safe either, because the Treponema pallidum is very small, only 5~15×0.1~0.2 microns, and about 10,000 spirochetes are as thick as a hair, so if the condom is slightly damaged, the Treponema pallidum will slip in.

2

Indirect contact transmission

This is a secondary route of transmission of syphilis. People who live with syphilis patients may be infected if they come into contact with the patients' used underwear, underpants, bedding, towels, razors, bath towels, bathtubs, toilets, etc. Cups and bowls can infect the lips, corners of the mouth or tongue, toilet seats can infect the buttocks and back of the thighs, and bedding can infect the skin of the whole body. The virus can survive for several hours in moist utensils or wet towels.

3

Mother-to-child transmission

If a woman with syphilis is not treated, the Treponema pallidum in her body can be transmitted to the fetus through the blood circulation of the placenta and the umbilical cord after she becomes pregnant, causing the fetus to be infected with syphilis. This mode of transmission is called fetal syphilis.

4

Hematogenous transmission

If the blood donor is a patient with latent syphilis or syphilis, the blood he or she provides is likely to contain Treponema pallidum, which can cause infection once it is transfused into the recipient's body.

5

Nosocomial transmission

Failure to strictly sterilize the instruments used in medical operations can cause nosocomial infection. This is mainly caused by unsterilized or incompletely sterilized syringes, surgical instruments, and other medical instruments that pierce the skin or mucous membranes, which can cause transmission between patients and between doctors and patients. Another form of nosocomial transmission mainly includes artificial insemination and organ transplantation.

From the above explanations of the transmission routes, we know that the possibility of contracting syphilis through regular use of public facilities and entering and exiting public places, such as swimming in swimming pools, touching toilet seats, sharing tableware, and touching clothing, is extremely low.

Image source: piqsels

In addition, the water in the swimming pool usually contains disinfectants such as bleaching powder, which is not suitable for the survival of sexually transmitted disease pathogens such as gonococci and syphilis spirochetes. Therefore, there is almost no possibility of contracting syphilis in a regular swimming pool.

For those who are afraid of contracting syphilis from staying in a hotel, it is important to know that Treponema pallidum is an anaerobic parasite that can survive in the human body for a long time, but not in the body. Towels, sheets and other items in hotels are washed with bleach and disinfectant, so Treponema pallidum is unlikely to remain on them.

Treponema pallidum can be killed in a short time in a dry environment or by using soapy water and general disinfectants such as 1:1000 phenol, chlorhexidine, and low-concentration alcohol. It will die in 1-2 hours in a dry environment. It will die in the blood at 4°C for 3 days, so blood stored in the blood bank refrigerator for more than 3 days is not infectious.

High temperature also has a great impact on Treponema pallidum. It can live for 1 to 2 hours at 41-42℃, lose its infectivity in just 30 minutes at 48℃, and die immediately at 100℃. It has strong resistance to cold and can live for 48 hours at 0℃. If the syphilis skin lesion specimen is placed in the refrigerator, it can still infect the human body and cause disease after 1 week. It can maintain its morphology, activity and toxicity when stored at low temperature (minus 78℃) for several years. It can live for about 10 hours in the tissue fluid diluted with sealed physiological saline.

"Latent" syphilis,

There will be these three discomfort symptoms!

In recent years, the number of syphilis cases has increased rapidly year by year, ranking third among infectious diseases after tuberculosis and hepatitis. This rapid growth began in the late 1990s, when the number of reported syphilis cases in the country increased significantly.

Syphilis has different symptoms at different stages.

In primary syphilis, a painless round lump will appear at the site of infection, which will then form an ulcer that will heal on its own even without treatment.

The first stage of syphilis chancre on the finger, image source: wikipedia

Secondary syphilis will cause syphilitic rash all over the body, including macules, papules, pustular syphilitic rash, etc., and the lymph nodes will also swell;

Typical manifestation of secondary syphilis: rash on the palms

Image source: wikipedia

Many parts of the body have red papules and nodules due to secondary syphilis. Image source: Wikipedia

Tertiary syphilis causes damage to the skin and mucous membranes, lesions in internal organs, and in severe cases, damage to the central nervous system.

A patient suffering from tertiary syphilis (syphiloma). Bust in the Museum of Humanity in Paris, Image source: Wikipedia

Primary and secondary syphilis are called early syphilis. Although syphilis is highly contagious at this time, it is also relatively easy to treat. However, it is difficult to cure after entering the late stage, so once syphilis is discovered, it must be treated early.

References

[1] Etiology and risk factors of syphilis, Mou Kuanhou [J] Chinese Medical Abstracts, Vol. 32, No. 4, August 2015

[2] O'Rourke E1, Schweon S. Syphillis［J］． Still a public health danger, 2007, 70(7): 26-31．

[3] Toriello PV, Menichetti CP, Buendía CB, et al. Combined norms for the prevention of vertical transmission of HIV and syphillisinfection［J］． Ｒev ChilenaInfectol, 2013, 30 (3): 259-302．

Planning and production

Author: Xu Lang, popular science creator

Review | Cheng Fang, deputy chief physician of the Dermatology Department of Xingtai People's Hospital

Planning丨Cui Yinghao

Editors: Cui Yinghao and Jin Yufen (Intern)