Virus WAtch Week Ending 26 July 2015
Influenza and Influenza-like Illnesses (ILI)
Summary: Taken together, direct and indirect indicators suggest that influenza virus activity may have now peaked, earlier than in recent seasons. Non-influenza virus activity also declined this week.
- ILI presentations to sentinel general practitioners (GPs) decreased this week and presentations to sentinel emergency departments (EDs) were steady.
- Influenza virus detections, notifications and percent positivity appear to have reached a peak. Influenza B (68%) and influenza A/H3N2 (29%) viruses remaining the dominantly detected subtypes. The influenza B strains currently circulating are around 65% Yamagata lineage, matching the trivalent influenza vaccine strain.
- Hospitalisations with confirmed influenza decreased this week, but remain over 10 cases per 1000 admissions. Over 70% of influenza admissions are due to influenza B virus, reflecting overall detections in the community.
- Non-influenza respiratory virus activity decreased this week, primarily due to a drop in respiratory syncytial virus detections.
Gastroenteritis
- Gastroenteritis presentations to sentinel GPs and EDs are relatively steady and consistent with levels experienced previously at this time of the year.
- Rotavirus detections declined this week.
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 confirmed.
- Several further cases of mumps have been confirmed in the Kimberley region, primarily among Aboriginal children, teenagers and young adults. Most recent cases are residents of Broome or nearby communities.
