Virus WAtch Week Ending 23 August 2015

Megan Reilly

Virus WAtch Week Ending 23 August 2015

Influenza and Influenza-like Illnesses (ILI)

Summary: Indicators of influenza activity increased slightly, but still suggest we are approaching the peak of the influenza season. The majority of non-influenza viruses remained steady or declined.

  • ILI presentations to sentinel general practitioners (GPs) and emergency departments (EDs) increased marginally but remain within ranges seen in recent mild influenza seasons.
  • Influenza virus detections, notifications and percent positivity are fluctuating within levels seen in recent mild seasons. Influenza B virus (55% of detections) continues to predominate; influenza A/H3N2 comprised 38% of subtyped cases this week.
  • Of the influenza B subtypes that have lineage data, 22% are Victoria and 78% are Yamagata, the latter consistent with the trivalent vaccine formulation.
  • Hospitalisations with confirmed influenza remain stable and below the average observed at this time in recent seasons. The majority (52.5%) of hospitalisations were for influenza B.
  • Non-influenza respiratory virus activity remained stable or decreased, with exception or rhinovirus which increased slightly.


  • Gastroenteritis presentations to sentinel GPs decreased and sentinel EDs remained stable; these are consistent with levels experienced previously at this time of the year.
  • Norovirus detections are low and steady, and rotavirus detections decreased this week.

 Varicella and Viral Rashes

  • Shingles and chickenpox presentations to sentinel EDs and GPs are near or below baseline levels.
  • No cases of measles or rubella were confirmed.

Further cases of mumps have been confirmed in the Kimberley and Pilbara regions, primarily among Aboriginal children, teenagers and young adults. Most recent cases are residents of Broome or Port Hedland, or nearby communities.