A review of listeriosis notifications and co-existing conditions in New South Wales, 2010-2015

Abstract

AIM: To describe the distribution of known risk factors for listeria infection, including co-existing conditions, among listeriosis notifications in NSW between 2010 and 2015. METHODS: Data from all notifications of invasive listeriosis in NSW between 01 January 2010 and 31 December 2015 were extracted from the NSW Notifiable Conditions Information Management System (NCIMS). OzFoodNet Listeria Case Questionnaires for each notification were reviewed. Descriptive analyses of notification data were undertaken. RESULTS: Between 2010 and 2015, there were 158 listeriosis notifications in NSW with an average of 26.3 notifications a year. Persons over 65 years represented 71.5% of all notifications. A total of 4.4% notifications were among pregnant women, while 79.1% and 64.6% were among persons with a condition and on treatment, respectively, known to supress the immune response or increase the risk of infection. Specifically, cancer patients and persons on cancer treatment (chemotherapy, radiotherapy) represented 31.0% and 13.9%, respectively, of all listeriosis notifications. Information on foods to avoid in preventing listeria from a healthcare worker prior to infection was received by 7.2% of notifications with a known risk condition and 5.9% of notifications on medication; 41.6% and 46.1% respectively had visited a hospital in the four weeks prior to notification. CONCLUSIONS: The prevalence of known risk factors for listeriosis among notified cases remains significant in NSW. Improved risk communication for this population, starting with information from healthcare professionals, may be beneficial in reducing the burden of listeriosis in known vulnerable groups who have regular contact with the health system.