The influenza surveillance program aims to assist in the early
detection of influenza, define distribution of influenza in the
community and provide timely information regarding circulating
strains.
Sentinel Surveillance
The sentinel influenza surveillance program with laboratory
support has been conducted in Victoria since 1998. Surveillance
is usually conducted over a 22 week period between May and September
each year.
Participation of metropolitan and rural general practitioners
(GPs) is on a voluntary basis. GPs are requested to report their
total number of weekly consultations and consultations for influenza-like
illness (ILI). GPs are also able to take nose and throat swabs
from patients who fulfill the case definition for influenza (fever,
cough and fatigue) and present within 3 days of onset of symptoms.
All specimens are tested at VIDRL using an in-house respiratory
multiplex PCR assay. This assay identifies influenza A (H3N2),
influenza A (H1N1), influenza B, adenovirus, picornavirus, respiratory
syncytial virus, and parainfluenza virus.
Where influenza virus is detected, an aliquot of the original
specimen is forwarded for further analysis to the WHO (World Health
Organization) Collaborating Centre for Influenza Reference and
Research in Melbourne.
Victoria's level of ILI activity is reported using a range of
threshold values. Baseline activity is <0.25 ILI consultations
per 100 patients seen, normal seasonal activity is 0.25-1.5 ILI
consultations per 100 patients seen, higher than expected activity
is 1.5 - 3.5 ILI per 100 patients seen and ILI activity above
3.5 consultations per 100 patients is defined as an epidemic.
Laboratory-based Surveillance
Four diagnostic laboratories in metropolitan Melbourne contribute
to surveillance data.
Melbourne Medical Deputising Service (MMDS) Surveillance
The MMDS surveillance project commenced in 2003. MMDS provides
a deputising medical service throughout Melbourne. Each week doctors
from the MMDS see about 1350 patients, which is approximately
30% of the number of patients seen each week in the sentinel general
practices contributing to ILI surveillance in Melbourne. The aim
is to examine whether the MMDS can supplement or, in the future,
replace existing sentinel general practice surveillance sites.
Reporting
Reports are generated on a fortnightly basis during the influenza
season.
To read more about influenza surveillance download our reports
GP
login for the Victorian Influenza Vaccine Effectiveness Audit
Interested in becoming a sentinel surveillance practitioner?
Contact Kristina Grant
