OBJECTIVE:
To
assess the ability of the national case definition to identify infectious
syphilis during an outbreak affecting predominantly Aboriginal and Torres
Strait Islander people in a remote Australian region.
METHODS:
A
retrospective case series study of all non-congenital syphilis cases in the
region notified between 1 January 2009 and 31 December 2012 was performed. The
national infectious syphilis case definition was compared with an expanded case
definition derived from experienced clinician assessment and the definition
proposed in the Interim Guidelines for the Public Health Management of Syphilis
Outbreaks in Remote Populations in Australia from the Communicable Diseases
Network Australia (CDNA).
RESULTS:
Two
hundred and forty syphilis cases were notified, of which 44 (18.3%) were
symptomatic. The national case definition classified 106 (44.2%) cases as
infectious, compared with 182 (75.8%) using the clinician-derived expanded case
definition and 165 (68.8%) by the interim guidelines case definition. Seven
confirmed and 6 probable cases were diagnosed as a result of contact tracing of
probable infectious cases identified using the expanded case definition.
CONCLUSIONS AND IMPLICATIONS:
The
national case definition for infectious syphilis applied in this remote
Australian outbreak underestimated infectious cases when compared with
experienced clinicians' evaluation by up to 76 cases (42%) and was inadequate
to monitor the magnitude of a syphilis outbreak in such a setting. This may compromise
surveillance and resource allocation decisions, and could reduce the capacity
to interrupt transmission and contain an outbreak. A revised national case
definition, informed by this analysis, was released by CDNA in July 2015.
Below: Epidemic curve of infectious syphilis in a north Queensland district, 2009 to 2012, by national definition, expanded case definition and Interim Guidelines case definition
- 1Public Health Physician (Sexual Health), Tropical Public Health Services, Cairns, Queensland.
- 2Clinical Director Sexual Health, John Hunter Hospital, Hunter New England Local Health District, New South Wales.
- 3Manager Health Surveillance, Tropical Public Health Services, Cairns, Queensland.
- 4Adjunct Associate Professor, James Cook University, Cairns, Queensland.
No comments:
Post a Comment