Syphilis

Notification requirement for syphilis

Syphilis is a ‘routine’ notifiable condition and must be notified by medical practitioners and pathology services in writing within 5 days of diagnosis.

This is a Victorian statutory requirement.

Specific information must be notified under the Public Health and Wellbeing Regulations 2009. To maintain confidentiality, only the name code (the first two letters of the surname followed by the first two letters of the first name) is required. A questionnaire is sent to the diagnosing doctor to collect additional information on the case that is essential for detecting disease trends and informing policy development.

Medical practitioners have a statutory obligation under the Children, Youth and Families Act 2005 to notify the department’s Child Protection service if they believe that a child is in need of protection on the basis of sexual abuse.

Primary school and children’s services centre exclusion for syphilis

Exclusion is not applicable.

Infectious agent of syphilis

The spirochaete Treponema pallidum subspecies pallidum is the infective agent.

Identification of syphilis

Clinical features

Syphilis is characterised by a primary ulcerative and classically painless lesion (chancre), a secondary eruption involving skin and mucous membranes, long periods of latency, and late lesions of skin, bone, viscera, cardiovascular and central nervous systems.

The stages of syphilis can be divided into:

• early syphilis, where primary (chancre), secondary (rash or condylomata lata) or latent syphilis (asymptomatic) of less than 2 years duration exists, based on serology results
• late latent syphilis, where latent syphilis has existed for 2 or more years or an indeterminate duration, in the absence of neurosyphilis, and other symptoms and signs of disease
• tertiary syphilis, where cardiovascular involvement and/or neurosyphilis is present.

Syphilis in pregnancy

Fetal infection may result in abortion, stillbirth, premature delivery and perinatal death. In congenital syphilis, generalised systemic disease in the live-born infant is present, which may have significant long-term complications if left untreated.

Diagnosis

Syphilis can be diagnosed by the demonstration of spirochaetes in the exudate from primary chancres or from the mucous membrane lesions of secondary syphilis, using dark-field microscopy or immunofluorescence.

Dark-field microscopy is a difficult technique and requires an experienced operator for reliable results. The test is unreliable on mucous membrane lesions because of the presence of morphologically similar saprophytic spirochaetes. Dark-field microscopy is best done on site, as drying of the exudate during transport to the laboratory renders the specimen unsuitable for microscopy. Immunofluorescence is more sensitive and does not have to be performed immediately. It is suitable for use with mucous membrane lesions but is not currently performed by the Victorian Infectious Diseases Reference Laboratory.

More commonly, syphilis is diagnosed using a combination of treponemal and nontreponemal serological tests:

• Treponemal tests measure specific treponemal antibodies in serum. They include T. pallidum particle agglutination, enzyme immunoassay and fluorescent treponemal antibody absorption tests. Once these tests are reactive, they usually remain so for life and give no indication of current disease activity. Enzyme immunoassays with highly purified T. pallidum antigens are becoming more commonly used for screening for syphilis. These assays have a high specificity and sensitivity. IgM enzyme immunoassay for the detection of IgM antibodies to T. pallidum is a useful assay for the diagnosis of congenital syphilis.
• Nontreponemal tests such as rapid plasma reagin (RPR) and venereal diseases research laboratory (VDRL) test measure antibodies that are produced in response to syphilis and also to a relatively large number of other conditions. This can result in biological false positives. The nontreponemal test gives an indication of current disease activity.

All sera showing reactive serology on screening tests should be forwarded to a reference laboratory for confirmatory testing.

It is necessary to interpret syphilis serology in the context of:

• clinical history and examination
• serial RPR titres tested in parallel, where possible (results obtained from different laboratories are not directly comparable)
• treponemal test results
• a past record of treatment.

It is essential that all cases of syphilis receive close clinical and laboratory follow-up.

Lumbar puncture is advised with:

• neurological or ophthalmic signs or symptoms
• evidence of active tertiary syphilis
• treatment failure
• HIV infection with late latent syphilis or syphilis of unknown duration.

Note that other sexually transmissible infections may be present in addition to syphilis. Patients in whom syphilis is diagnosed should be encouraged to be tested for HIV infection.

Incubation period of Treponema pallidum

The incubation period is from 10 days to 3 months and is usually 3 weeks.

Public health significance and occurrence of syphilis

This is a complex disease. Sequelae include neurosyphilis, cardiovascular syphilis, and congenital infection with fetal death, stillbirth and abortion. Testing and effective treatment are available to facilitate the interruption of disease transmission. Immune responses are only partially protective, and reinfection may occur following treatment. Syphilis enhances the transmission of HIV, like other diseases that cause genital ulcers.

Syphilis occurs worldwide and has a high incidence in regions outside Victoria. Other developed countries have experienced recent outbreaks. Imported infectious cases could result in syphilis re-emerging as a significant public health issue.

Reservoir of Treponema pallidum

Humans are the only reservoir.

Mode of transmission of Treponema pallidum

Transmission occurs primarily by sexual contact. Transplacental infection of a fetus may occur during the pregnancy of an infected woman. Fetal infection occurs with high frequency in untreated early infections of pregnant women, and with lower frequency later in the disease or in late latency.

Period of communicability of syphilis

A case is considered sexually infectious until the end of the early latent period, which is approximately 2 years after infection. Infectious moist mucocutaneous lesions are present in the primary and secondary stages of syphilis, and may recur intermittently in the early latent period. These lesions may not be apparent to the infected individual.

Susceptibility and resistance to syphilis

Everyone is susceptible to infection.

Control measures for syphilis

Preventive measures

Education about safe sex practices, including the use of condoms, and early detection of infection by testing of people at risk are the main preventive measures.

Control of case

Penicillin is the drug of choice to treat syphilis.

Further information on the clinical management of patients with syphilis can be found in the latest edition of Therapeutic guidelines: antibiotic.

Because of the requirement for long-term follow-up and possible complications, it is advisable to seek specialist advice for management.

Control of contacts

Sexual contacts should be identified. The extent of contact tracing depends on the clinical stage of infection.

For primary syphilis, all people having sexual contact with the index case during the 3 months preceding onset should be evaluated. Such contacts should be treated as for the case, even if their serology is negative.

For secondary syphilis, this period should be extended to 6 months and, for early latent syphilis, to 12 months.

For late latent syphilis, any sexual partners and children of infected women should be evaluated.

For congenital syphilis, all members of the immediate family should be evaluated.

Contact tracing assistance can be provided by the department’s notification officers.

All newborns of mothers with syphilis should be investigated and treated in consultation with a specialist.

Control of environment

Not applicable.

Outbreak measures for syphilis

Not applicable.

More information

For more information, see the Syphilis decision making tool on the Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine's website.

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