Diseases Under Surveillance
Ross River virus
VEDS users, please note that a new case definition for Ross River virus (RRv) was implemented nationally on 1 January 2016. The new case definition requires more specific laboratory evidence of infection and as such, there are notifications that would have been valid under the old case definition that are not under the new case definition (available at http://www.health.gov.au/internet/main/publishing.nsf/Content/cda-surveil-nndss-casedefs-cd_rrv.htm). However, this new case definition will provide more accurate reporting of RRv disease in the community as the potential for non-cases to be reported has been reduced.
This new case definition was implemented in Queensland in September 2016, and was retrospectively applied to all cases of RRv notified from 1 January 2016 onwards. As a result of applying the case definition retrospectively, approximately a third of RRv notifications were invalidated statewide. Please consider this when reviewing notifications of RRv in your area, noting that comparisons of the number of notifications before and after this change will differ based on the case definitions used and may not be a reflection of differences in disease in the community.
Barmah Forest virus
A similar change was implemented in the Barmah Forest virus case definition on 1 January 2016 (http://www.health.gov.au/internet/main/publishing.nsf/Content/cda-surveil-nndss-casedefs-cd_bfv.htm), though it had a less significant impact on the number of cases notified. This should still be taken into account when comparing the number of cases reported with previous years.