Annual report concerning Foodborne Diseases in New Zealand 2019

ESR Report FW20013

Human health surveillance and its relationship to foodborne illness is essential for informing the strategic direction that New Zealand Food Safety (NZFS) takes and regulatory measures it puts in place to minimise foodborne illness in New Zealand and overseas consumers.

The annual ESR foodborne disease reports are critical, allowing NZFS to monitor trends in foodborne illness in New Zealand by describing in a consistent manner evidence from notifications, case enquiries, outbreak investigations and other epidemiological studies of human enteric diseases.

This report forms part of a series providing a consistent source of data annually to monitor trends on foodborne illness in New Zealand. The series can be found here. The reduction of human cases of foodborne campylobacteriosis is a top priority for NZFS. The current performance target is a reduction of rates of foodborne campylobacteriosis by 10% from 88.4in 2015to 79.6 by the end 2020.

Progress toward this target is reported in the section entitled Reporting against targets. The surveillance data indicates that during the last ten years the rates of foodborne campylobacteriosis are consistently, albeit slowly, decreasing. NZFS underscores that both total numbers of campylobacteriosis cases and rates per 100,000 population notified in 2019 are the lowest since 1992.Since 2015, NZ diagnostic laboratories have started to replace traditional culture-based methods for enteric pathogens by culture-independent diagnostic tests(CIDT)using molecular polymerase chain reaction.

In 2019, about 78% of human faecal samples were tested using CIDT. However, different laboratories are using different CIDT and six DHBs continue to use culture-based testing methods for enteric pathogens. The implication of improved sensitivity and changes in number of tests is well described in the introduction to the 2019 report. Shiga toxigenic Escherichia coli (STEC) remains a focus for NZFS. A continuing sharp increase in notification of STEC infections is evident, despite the absence of evidence that foodborne sources are increasing. The cause of this is likely to be related to implementation of CIDT and an increase in the number of faecal samples tested for STEC as all community faecal specimens are now screened for STEC.

The selection of diseases covered in the report is based on the potential of the disease to be caused by foodborne transmission and availability of national sources of information related to the disease. The enhanced analysis of risk factors and presentation of the information has resulted in an improved description of foodborne outbreaks in the 2019 report.

Although, some outbreaks reported as foodborne with unidentified food source might be attributed to other routes of transmission, such as water, animal contact or person to person. NZFS and ESR will further continue to improve the analysis and presentation of foodborne human illness surveillance and investigation data in future reports.