Virus WAtch Week Ending 19 July 2015

Megan Reilly

Virus WAtch Week Ending 19 July 2015

Influenza and Influenza-like Illnesses (ILI)

Summary: Non-influenza virus activity, particularly respiratory syncytial virus (RSV), remains high. Influenza activity, primarily due to influenza B virus, remains moderate in intensity.

  • ILI presentations to sentinel general practitioners (GPs) increased this week, but conversely presentations to sentinel emergency departments (EDs) decreased.
  • Influenza virus detections and notifications decreased for the second consecutive week, while percent positivity has fluctuated at around 20% over recent weeks.
  • Hospitalisations with confirmed influenza increased to 17.5 per 1000 admissions, similar to the average for this week in recent years. Over 60% of influenza admissions are due to influenza B virus.
  • Influenza B (68%) and influenza A/H3N2 (29%) viruses remain the dominantly detected subtypes. The influenza B strains currently circulating are around 80% Yamagata lineage, matching the trivalent influenza vaccine strain.
  • Non-influenza respiratory virus (particularly RSV) activity remains high.


  • Gastroenteritis presentations to sentinel GPs and EDs are relatively steady and consistent with levels experienced previously at this time of the year.
  • Rotavirus detections remain high. Rotavirus has caused recent outbreaks of gastroenteritis in residential care and childcare settings in metropolitan Perth.

Varicella and Viral Rashes

  • Chickenpox and shingles presentations to sentinel EDs and GPs are near or below baseline levels.
  • No cases of measles or rubella were notified.
  • Several further cases of mumps have been confirmed among Aboriginal children, teenagers and young adults in the Kimberley region, including in Broome.