Monthly Notifiable Disease Surveillance Report - Sep 2018

Enteric Diseases: Enteric infections are the most common notifiable diseases, and several are increasing in incidence. This increase is partly due to changes in laboratory testing practices with a shift from culture methods to multiplex PCR, which tests for several diseases at the same time. This means more diseases are likely to be detected and in a more timely manner. For further information, see the 2016 Annual Notifiable Disease Report Commentary.

Invasive pneumococcal disease: There were 84 cases (79 confirmed and 5 under investigation) of invasive pneumococcal disease notified in September 2018, compared with 46 for the same month in 2017. The majority of confirmed cases (48/79, 60.8%) were aged over 50 years. This represents the highest monthly total in 2018, which is two months later than the usual July peak in cases. For further information, see the invasive pneumococcal disease quarterly reports.

Legionellosis: There were 26 cases (12 confirmed, 1 probable and 13 under investigation) of legionellosis notified in September 2018, compared with 10 for the same month in 2017. All cases were aged over 30 years, and over half (14/26, 53.8%) were over 60 years. An increase is expected at this time of year due to exposure to compost and potting mix as part of spring gardening activities. For more information, see the ESR media release Legionella numbers on the rise.

Meningococcal Disease: There have been 19 cases of group W meningococcal disease from January to September 2018, compared with eight for the same period in 2017. One death due to group W was reported in September 2018. More information can be found in the March 2018 NZ Public Health Surveillance Report and in the May 2018 immunisation update.

Pertussis: There were 173 cases (97 confirmed, 63 probable, 7 suspect and 6 under investigation) of pertussis notified in September 2018, compared with 186 cases for the same period in 2017. While pertussis cases have been decreasing since the peak in January 2018, there is a possibility that cases may increase again, as in the 2012 outbreak. A national outbreak is ongoing. For more information see the latest Pertussis Report.

Yersiniosis: There have been 917 cases of yersiniosis notified from January to September 2018, compared with 681 for the same period in 2017. Recent changes in laboratory testing may have contributed to the substantial increase in cases in 2018.

OUTBREAKS

Influenza A: There were three influenza A virus outbreaks reported in September 2018, from Capital & Coast, Wairarapa and Whanganui DHBs. Two outbreaks were associated with schools, and one was in a long-term care facility. In addition, there was an acute respiratory infection outbreak at a long-term care facility reported from Bay of Plenty DHB. Community influenza activity peaked very late this season, in September. Further information on influenza surveillance can be found on the ESR website page Flu Surveillance and Research.