Virus Watch Week Ending 6 September 2015

Influenza and Influenza-like Illnesses (ILI)

Summary: Most direct and indirect indicators of influenza activity declined this week, suggesting we have passed the peak of the influenza season.

• ILI presentations to sentinel general practitioners (GPs) and emergency departments (EDs) decreased this week and are consistent with presentations rates during recent mild influenza seasons.
• Influenza virus detections, notifications and percent positivity decreased this week. The decline in overall influenza detections was almost entirely due to a 40% decrease in influenza B, with the result that the relative proportion of influenza A/H3N2 cases increased to 47% and influenza B declined to 46% of cases. Hospitalisations with confirmed influenza have been trending downwards over the past month, and are below the average observed at this time in recent seasons.
• Respiratory syncytial virus and other non-influenza respiratory virus activity continue to decline.

Gastroenteritis

• Gastroenteritis presentations to sentinel GPs and EDs remain low.
• Rotavirus detections have decreased over recent weeks and norovirus activity remains low and relatively stable.

 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. Activity has declined in the Kimberley and increased in the Pilbara over recent weeks.