Corkscrew-like Syphilis bacteria


Information and pictures on Syphilis, a common sexually transmitted disease. Information including symptoms, diagnosis, treatment, transmission, prevention and other general information.


Syphilis is a sexually transmitted disease (STD) caused by a bacterium (Treponema pallidum). The initial infection causes an ulcer at the site of infection.

Syphilis, once virtually untreatable, can nowadays be effectively diagnosed and treated with antibiotic therapy. Unfortunately some antibiotic resistant strains are developing so research must continue.

Early symptoms of syphilis are often very mild, and treatment is often not sought when first infected. Syphilis increases the risk of transmitting and receiving the human immunodeficiency virus (HIV). Over time, the bacteria moves throughout the body, causing damage to many organs.

The disease is divided into four stages:

  • primary
  • secondary
  • latent
  • tertiary (late)

An untreated infected person may infect others during the first 2 stages (1-2 years).

Even though untreated syphilis is not contagious in the late stage serious complications can occur:

  • blindness
  • mental disorders
  • neurological problems
  • serious heart abnormalities
  • death

In the fight against the spread of syphilis research is being carried out to find a vaccine and to study the effects the various surface components of the syphilis bacterium have on the immune system.

The genome of the bacterium has now been sequenced which will be invaluable in diagnosing, treating and vaccinating against syphilis.


Transmission of Syphilis

The bacterium can pass through broken skin on parts of the body. Syphilis can be spread via close skin-to-skin contact like that involved during sex. The moist areas such as the anus, genitals, and mouth are more susceptible to infection and the be contracted in any region of the body.

The Syphilis bacteria is highly contagious when there is the presence of an active outbreak of an ulcer, sore (chancre) or rash.

In an infected person the bacterium spreads from the initial ulcer to the skin or mucous membranes of:

  • the anus of a sexual partner
  • the genital area
  • the mouth

The syphilis bacterium is very fragile and infection is usually spread by:

  • an infected pregnant woman who can pass the bacterium to her unborn baby, which can result in the child being born with serious mental and physical problems
  • sexual contact


Syphilis Symptoms

Primary syphilis

First stage

  • An ulcer (a chancre ["shan-ker"]) appears within 10 days to 3 months after exposure, but usually within 2-6 weeks
  • The chancre may be painless and can remain undetected inside the body, so may go unnoticed

The chancre usually appears on the part of the body exposed to the partner’s ulcer, such as:

  • anus
  • cervix
  • lips
  • penis
  • tongue
  • vagina
  • vulva
  • other parts of the body

These usually disappear within a few weeks whether treated or not. If left untreated during the primary stage, about one-third will continue on to chronic stages.

Secondary syphilis

The most common symptoms include:

  • a rash of flat, red lesions over the whole body (including the palms of the hands and soles of the feet)
  • fever
  • swollen glands
  • broad-based papules (lumps or warts) in warm, moist sites
  • mucous patches or snail-track ulcers in the mouth, appearing from 3-6 weeks after the chancre develops

Active bacteria are present in the sores, so physical contact (sexual or nonsexual) with the broken skin of an infected person is not recommended as transmission of the disease is possible.

After several weeks or months the rash seems to heal itself.

Other symptoms such as:

  • fatigue
  • headache
  • mild fever
  • patchy hair loss
  • sore throat
  • swollen lymph glands throughout the body

also may occur but will usually disappear without treatment.

The secondary stage of secondary syphilis appears 2-4 months after infection, lasting several weeks and often recurring in the following 2 years and can come and go over the next1-2 years.

Latent stage syphilis

A stage of infection caused by T. pallidum in which organisms persist in the infected person’s body without causing symptoms or signs.

Latent syphilis is subdivided into:


  • initial infection occurring within the previous 12 months


  • initial infection has occurred greater than 1 year previously)

Unknown categories

  • based on the duration of infection
  • no evidence of having acquired the disease within the preceding 12 months

Tertiary (Late) syphilis

A minority (up to 30%) of individuals with untreated syphilis may develop tertiary syphilis with lesions many years after the initial infection.

The lesions can be benign, causing no serious disability, or they may involve the:

  • brain
  • eyes
  • nervous system
  • joints
  • spinal cord (neuro-syphilis)

as well as

heart and blood vessels (cardiovascular syphilis), producing severe complications resulting in :

  • blindness
  • heart disease
  • mental illness
  • other neurological problems
  • death

Some syphilis cases (especially latent or late stages), need to have a lumbar puncture (spinal tap) to check for infection of the nervous system.

Other clinical signs of syphilis (late) include:

Inflammatory lesions of the:

  • bones
  • cardiovascular system
  • skin

Occasionally other areas of the body may be affected such as:

  • abdominal organs
  • eyes
  • lymph nodes
  • mouth
  • reproductive organs
  • upper and lower respiratory tracts

Late syphilis usually becomes apparent after 15-30 years of untreated infection.


The bacteria often invades the central nervous system during the early stages of infection. Approximately 3-7% of persons with untreated syphilis develop neuro-syphilis.

Some people never develop any symptoms, some experience headache, stiff neck, and fever, resulting from inflammation of the lining of the brain and others develop seizures.

Blood vessels affected by the bacteria can result in symptoms similar to a stroke:

  • numbness
  • visual complaints
  • weakness

It has been known to take up to 20 years to develop neuro-syphilis. Neuro-syphilis is difficult to treat especially for those with HIV infection. Elevated CSF protein or leukocyte count in the absence of other known causes of these abnormalities may occur.

The widespread use of antibiotics makes modern-day syphilis harder to detect as there may be no genital symptoms, or any symptoms of secondary syphilis.

Effects of Syphilis in Pregnant Women

An untreated pregnant woman with active syphilis will pass the infection to her unborn child:

  • about 25% will have stillbirth or neonatal death
  • 40-70% will have syphilis-infected babies

Hepatitis screening should be done as well. A fetal death taking place after a 20-week gestation or if the fetus weighs more than 500 gms with an untreated mother at delivery is classified as a syphilitic stillbirth.

Babies with congenital syphilis can have symptoms at birth, but symptoms can develop two weeks to three months later, including:

  • anemia
  • fever
  • rashes
  • skin sores*
  • swollen liver and spleen
  • various deformities
  • weak/hoarse crying sounds
  • yellowish skin (jaundice)

*The moist sores of congenital syphilis are infectious.

When infected infants become older children and teenagers, late-stage syphilis symptoms may occur, including damage to:

  • bones
  • brain
  • eyes
  • ears
  • teeth

The rise in infant syphilis morbidity (death) has become a public health concern that warrants attention.


Photos of Syphilis Symptoms


Syphilis Diagnosis & Testing

Because its early symptoms are similar to many other conditions people who are sexually active should consult a doctor about any unusual rash or sore in the genital area.

Three methods may be used in diagnosis of syphilis:

  • blood tests
  • microscopic identification of syphilis bacteria
  • recognition of the signs and symptoms during normal medical consultation

Bacteria Identification

A surface scraping from the ulcer or chancre is taken and examined under a special ‘darkfield’ microscope to detect the organism itself.

Accurate clinical diagnosis in the newborn is possible only with positive ‘darkfield’ findings from skin lesions or placenta, or congenital syphilis classical signs seen on examination.

Cord blood should not be used for infant serologic testing because the high incidence of false positives and false negatives is high.

Blood Tests

Evidence of infection is given. False-negative results which do not show signs of infection despite its presence can appear for up to 3 months after infection. False-positive tests also occur, therefore, two blood tests are normally used.

t is sometimes difficult to interpret blood tests for syphilis so repeated tests are often necessary to confirm the diagnosis.

The blood-screening tests most often used are:

  • RPR (rapid plasma reagin) test
  • VDRL (Venereal Disease Research Laboratory) test

False-positive results showing signs of infection when it is not present occur in people with:

  • autoimmune disorders
  • certain viral infections
  • other condition

A confirmatory blood test is carried out when the initial test is positive, such as:

  • The fluorescent treponemal antibody-absorption (FTA-ABS) test (70-90% accuracy)
  • T. pallidum hemagglutination assay (TPHA) test

Syphilis antibodies (proteins made by a person’s immune system to fight infection) can be detected. These antibodies do not protect against syphilis infection in a previously infected person because once antibodies are formed, they remain in the body for many years.

It is hoped that a diagnostic test that does not require a blood sample can be produced. Tests are being carried out on saliva and urine to see if they produce comparable results to blood.


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Syphilis Treatment

Syphilis is treated with penicillin, usually administered by injection. A person no longer usually transmits syphilis 24 hours after beginning treatment.

Some people, however, do not respond to the usual doses of penicillin, therefore, it is important that people being treated for syphilis have periodic blood tests to check that the bacteria has been completely destroyed. Persons with neuro-syphilis may need to be retested for up to 2 years after treatment.

People with an allergic reaction to penicillin should consult their doctor for appropriate antibiotic advice. Safe, effective, single-dose oral antibiotic treatment for syphilis is being sought for people who are allergic to penicillin (10% of population).

Proper treatment in all stages of the disease will cure the disease, but in late syphilis, damage already done to body organs cannot be reversed.

The serology or treatment of infected pregnant women under certain conditions may present unusual signs. HIV positive persons may have unusual syphilitic infections often with central nervous system involvement.

Treatment failures although rare do happen with subsequent advancing to neuro-syphilis, because of an impaired cellular or hormonal immune response in the HIV infected person leading to an altered presentation of syphilis (Seronegative secondary syphilis).

Repeated blood tests are necessary for at least a year after treatment to monitor possible treatment failure. People who have had tertiary syphilis should be followed up for many years.

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Prevention of Syphilis Infections

During the active stages of infection open sores may be visible and infectious. Any contact with infected sores, infected tissues and body fluids must be avoided to prevent spread of the disease.

Methods of prevention include:

  • screening and treatment of infected individuals, or secondary prevention, is needed to halt advanced stages.
  • using condoms during sex

Testing and treatment early in pregnancy as a routine part of prenatal care is the best way to prevent congenital syphilis in infants. Health personnel working with the newborn should be aware of cases and notify the appropriate authorities, within 72 hours of discovery, who will give care and follow-up treatment.

Early detection and treatment of syphilis is essential in order to have a significant impact on slowing the occurrence of this potentially fatal disease.