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Australian national notifiable diseases case definitions

Syphilis (congenital) case definition

This document contains the case definitions for Congenital syphilis which is nationally notifiable within Australia. This definition should be used to determine whether a case should be notified.

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Surveillance case definition

Version	Status	Last reviewed	Endorsement date	Implementation date
1.1	Confirmed Case: ‘Laboratory Suggestive and Clinical evidence’ moved to define a Probable Case. Probable Case: Structure and content of ‘Probable Case’ section amended to be consistent with Case Definition style guide and comprise Laboratory Suggestive and Clinical evidence. Lab Definitive evidence: Extensive rework of section including: removal of specific reference to treponemal IgM assays; inclusion of requirement that NAT and other tests be corroborated; broadening of the specimen sites which might get tested; adding criteria allowing for the persistence of antibody in infants to count as definitive. Lab Suggestive evidence: Reworking of section including: removal of specific reference to IgM assays; removing NAT from a non-sterile site (now definitive evidence if corroborated); adding seropositivity in either child or mother. Clinical Evidence: Structure and content of ‘Clinical Evidence’ section amended to be consistent with Case Definition style guide. ‘Asymptomatic infection’, ‘Foetal death in utero’ and ‘Stillbirth in a foetus greater than 20 weeks gestation’ removed from criteria, but accounted for in the notes; details of clinical evidence also removed; rewording of the clause defining inadequate maternal treatment; moving laboratory evidence into appropriate sections.	CDWG O-O-S January 2010	CDNA 29 September 2010	1 January 2011
1.0	Initial case definition (2004).

Reporting

Both confirmed cases and probable cases should be notified.

Confirmed case

A confirmed case requires laboratory definitive evidence.

Laboratory definitive evidence¹

1. Demonstration of Treponema pallidum by any two of the following: fluorescent antibody, nucleic acid test, dark field microscopy and silver stain; in specimens from lesions, placenta, umbilical cord, cerebrospinal fluid (CSF), amniotic fluid or autopsy material

OR

2. Mother and child both seropositive by a treponemal test² and the child’s serum non-treponemal³ serology titre is at least fourfold greater than the mother's titre at birth

OR

3. A child who remains seropositive by a treponemal test² at 15 months of age, which is confirmed either by another, different reactive treponemal test or a reactive non-treponemal test,³ in the absence of documented post-natal exposure to Treponema pallidum

OR

4. A reactive CSF Venereal Disease Research Laboratory (VDRL) titre in a child.

Probable case

A probable case requires laboratory suggestive evidence AND clinical evidence.

Laboratory suggestive evidence¹

1. Dark field microscopy of lesion exudate or node aspirate smears (not oral lesions) to demonstrate characteristic morphology and motility of Treponema pallidum

OR

2. Demonstration of Treponema pallidum in tissues by special (e.g. silver) stains

OR

3. A child or mother is seropositive by a treponemal test,² confirmed either by another different reactive treponemal test or a reactive non-treponemal test.³

Clinical evidence

1. Any evidence of congenital syphilis on physical examination

OR

2. Any evidence of congenital syphilis on radiographs of long bones

OR

3. An elevated CSF cell count or protein (without other cause)

OR

4. The mother is seropositive in the perinatal period AND has no documented evidence of adequate treatment prior to the pregnancy4 AND has not been adequately treated for syphilis during the pregnancy.^4,5

Notes:

1 Laboratory definitive evidence or laboratory suggestive evidence in a stillbirth where the foetal death has occurred after a 20 week gestation or in a foetus which weighs greater than 500g should be counted as evidence towards a case

2 Treponemal tests are; IgG enzyme immunoassay, Treponema pallidum haemagglutination assay, Treponema pallidum particle agglutination assay, Treponema pallidum immobilisation assay, Fluorescent Treponemal Antibody Absorption, 19S-IgM antibody test, or IgM enzyme-linked immunosorbent assay

3 Non-treponemal tests are; Rapid Plasma Reagin (RPR), Venereal Disease Research Laboratory

4 Treatment prior to pregnancy is considered adequate if:

4.1  An appropriate regimen was used and an adequate maternal serological response to treatment documented (early syphilis: decline in RPR of at least 2 titres or 4-fold; late latent syphilis: if no reduction in RPR then maintenance of a low stable titre)

4.2  A low stable titre is less than 1 in 8 and not rising more than 1.  All RPRs during pregnancy and at delivery are stable (within one titre) and no higher than 1:4

4.3  All antenatal and delivery pathology investigations performed and results verified

(Note in the presence of untreated syphilis, the birth of an unaffected child does not guarantee that subsequent children will not be affected)

5 Adequate treatment during pregnancy is:

5.1  appropriate penicillin treatment completed thirty days or more prior to delivery, with adequate serological response to treatment documented prior to or at delivery as defined in 4.2.