National case definition: Syphilis

Date of last revision/review: May 2008

National notification

Only confirmed cases of disease should be notified

Type of surveillance

Routine case-by-case notification to the federal level

Case classification

Confirmed case: Primary syphilis

Laboratory confirmation of infection:

• identification of T. pallidum by dark-field microscopy, fluorescent antibody, nucleic acid testing, or equivalent examination of material from a chancre or a regional lymph node

or

• presence of one or more typical lesions (chancres) and reactive treponemal serology, regardless of non-treponemal test reactivity, in individuals with no previous history of syphilis

or

• presence of one or more typical lesions (chancres) and a fourfold or greater increase in the titre over the last known non-treponemal test in individuals with a past history of syphilis treatment

Confirmed case: Secondary syphilis

Laboratory evidence of infection:

• identification of T. pallidum by dark-field microscopy, fluorescent antibody, nucleic acid testing or equivalent examination of mucocutaneous lesions, condylomata lata and reactive serology (non-treponemal and treponemal)

or

• presence of typical signs or symptoms of secondary syphilis (e.g. mucocutaneous lesions, alopecia, loss of eyelashes and lateral third of eyebrows, iritis, generalized lymphadenopathy, fever, malaise or splenomegaly) and either a reactive serology (non-treponemal and treponemal) or a fourfold or greater increase in titre over the previous known non-treponemal test

Confirmed case: Early latent syphilis (< 1 year after infection)

Laboratory confirmation of infection:

• an asymptomatic patient with reactive serology (treponemal and/or non-treponemal) who, within the previous 12 months, had one of the following:
  • non-reactive serology
  • symptoms suggestive of primary or secondary syphilis
  • exposure to a sexual partner with primary, secondary or early latent syphilis

Confirmed case: Late latent syphilis (> 1 year after infection or of unknown duration)

Laboratory confirmation of infection:

• an asymptomatic patient with persistently reactive treponemal serology (regardless of non-treponemal serology reactivity) who does not meet the criteria for early latent disease and who has not been previously treated for syphilis

Confirmed case: Neurosyphilis

Infectious (< 1 year after infection)

Laboratory confirmation of infection:

• Fits the criteria in for primary, secondary, or early latent syphilis above and one of the following:
  • reactive CSF-VDRL in non-bloody cerebrospinal fluid (CSF)
  • clinical evidence of neurosyphilis and either elevated CSF leukocytes or elevated CSF protein in the absence of other known causes

Non-infectious (> 1 year after infection)

Laboratory confirmation of infection:

• reactive treponemal serology (regardless of non-treponemal serology reactivity) and one of the following:
• reactive CSF-VDRL in non-bloody CSF
• clinical evidence of neurosyphilis and either elevated CSF leukocytes or elevated CSF protein in the absence of other known causes

Confirmed case: Tertiary syphilis other than neurosyphilis

Laboratory confirmation of infection:

• reactive treponemal serology (regardless of non-treponemal test reactivity) together with characteristic late abnormalities of the cardiovascular system, bone, skin or other structures, in the absence of other known causes of these abnormalities (T. pallidum is rarely seen in these lesions although, when present, it is diagnostic)

and

• no clinical or laboratory evidence of neurosyphilis

Laboratory comments

Diagnosis of syphilis requires a combination of history, including epidemiologic risk factors or exposure, physical examination and laboratory tests, as there is no single optimum diagnostic criterion.

Dark-field microscopy testing for T. pallidum is not reliable for oral/rectal lesions, as non-pathogenic treponemes may be present. Instead, direct fluorescent antibody test for T. pallidum should be used on such specimens.

ICD code(s)

ICD-11 code(s)

1A61, 1A62

ICD-10 code(s)

A51, A52

Comments

Each category is mutually exclusive.

The possibility of a prozone reaction should be considered in individuals who are suspected of having secondary syphilis but whose non-treponemal test is non-reactive.

A prozone reaction refers to a false-negative response resulting from overwhelming antibody titres that interfere with the proper formation of the antigen-antibody lattice network that is necessary to visualize a positive flocculation test.

References

Case definitions for diseases under national surveillance. CCDR 2000;26(S3).

Retrieved May 2008, from http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/00vol26/26s3/index.html