Improving foodborne disease surveillance in NSW

Abstract

Objective: To review enteric disease outbreaks reported to the NSW Department of Health. Methods: Data from existing electronic enteric disease outbreak summary databases were used to describe the number and type of outbreaks reported, burden of illness and cause of the outbreaks. Results: Between 2000 and 2005, 998 enteric disease outbreaks were reported (148 foodborne and 850 non-foodborne), affecting 24260 people and associated with 771 hospitalisations and 21 deaths. Salmonella was confirmed in 28 per cent of foodborne outbreaks, and norovirus in 18 per cent of non-foodborne outbreaks. Conclusions: Enteric disease outbreaks cause a substantial burden of disease in NSW. Michelle CretikosA,C, Barbara TelferB and Jeremy McAnultyB ANSW Public Health Officer Training Program, NSW Department of Health BCommunicable Diseases Branch, NSW Department of Health CCorresponding author: Email: mcret@doh.health.nsw.gov.au. breaks of gastroenteritis occur in institutions, such as schools, childcare centres and residential care facilities. Institutional outbreaks of gastroenteritis are usually caused by highly infectious viruses such as norovirus and rotavirus, and spread predominantly through person-toperson contact.1,5 Under the Public Health Act (NSW) 1991, 12 enteric conditions are currently notifiable in NSW and must be reported to NSW Health by doctors, laboratories and hospitals, including: botulism, cholera, cryptosporidiosis, giardiasis, haemolytic uraemic syndrome (HUS), shigatoxigenic Escherichia coli (STEC) infection, hepatitis A, hepatitis E, listeriosis, salmonellosis, shigellosis and typhoid. Some of these diseases are primarily foodborne in origin, such as salmonellosis, typhoid and listeriosis. In addition to individual disease notifications, outbreaks of suspected foodborne disease in two or more people related in time or place, and outbreaks of gastroenteritis among people of any age in an institution (eg an educational, residential, childcare or healthcare institution) are also notifiable by doctors and institutions. Where public health units identify clusters of disease or outbreaks, they will launch an outbreak investigation. Summary reports of enteric disease outbreaks are provided by public health units and entered into the relevant enteric disease outbreak databases held at the NSW Department of Health. We analysed enteric disease outbreaks reported to the NSW Department of Health for the five-year period July 2000–June 2005. This analysis aimed to describe the number, epidemiology and cause of the enteric disease outbreaks reported during this period. Methods The two existing NSW Health enteric disease outbreak databases – the OzFoodNet Outbreak Summary Database and the Gastroenteritis in Institutions Database – were used. For the purposes of the present study, the data contained within the two enteric disease outbreak summary databases was separated into two categories: • foodborne and suspected foodborne outbreaks, and • non-foodborne outbreaks of enteric disease. If the setting of the outbreak was an institution (ie aged care facility, hospital, child care centre, school, correctional facility or other institutional setting) and the method of transmission was unknown, the outbreak was assumed