Virus WAtch Week Ending 9 August 2015

Influenza and Influenza-like Illnesses (ILI)

Summary: Indicators of influenza activity remain relatively steady, indicating we may be at or near the peak of the influenza season. Non-influenza virus activity continues to decline.

• ILI presentations to sentinel general practitioners (GPs) and emergency departments (EDs) have plateaued.
• Influenza virus detections and notifications have plateaued, but percent positivity increased this week. Influenza B virus (61% of detections) continues to predominate, but is gradually declining in relative terms, with influenza A/H3N2 now comprising 32% of cases.
• Hospitalisations with confirmed influenza have plateaued and may be declining..
• Non-influenza respiratory virus activity, and particularly RSV, continued to decrease this week.

Gastroenteritis

• Gastroenteritis presentations to sentinel GPs and EDs are relatively steady and consistent with levels experienced previously at this time of the year.
• Norovirus detections are low and steady, and although rotavirus detections decreased this week, several rotavirus outbreaks have been identified recently in residential aged care and childcare facilities.

 Varicella and Viral Rashes

• Shingles and chickenpox presentations to sentinel EDs and GPs are near or below baseline levels.
• No cases of measles were confirmed.
• One probable case of rubella was reported in an unvaccinated young adult who had returned recently from Indonesia.

Several 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.