An outbreak of Salmonella typhimurium 108/170 at a privately catered barbeque at a Sydney sports club.

An outbreak of gastrointestinal illness was identified among attendees at a large community barbeque at a Sydney sports club on 30 January 2009. A retrospective cohort study was initiated, and attendees were identified through hospital emergency department gastroenteritis presentations, snowball recruitment through known cases, responders to linguistically specific press, and those returning to the venue the next week. A symptom and food history was collected from attendees, and stool samples were provided for microbiological investigation. An environmental investigation and trace back of implicated foods was also undertaken. Attendance estimates at the barbeque ranged from 100 to 180, and the food was prepared by a family that was not registered as a food business. Seventy one of the 87 attendees identified met the case definition. Thirty attendees (42%) had laboratory confirmed Salmonella Typhimurium phage-type 108/170, all with the same multilocus variable number of tandem repeat analysis typing. Burden of illness was high with 76% of cases seeking medical attention and 18% admitted to hospital. Microbiological evidence confirmed that a number of food items were contaminated with Salmonella Typhimurium 108/170, with the raw egg mayonnaise used in a Russian salad being the most likely primary food vehicle (adjusted odds ratio=10.3 [95% confidence interval 1.79-59.5]). Further, having Russian salad on the plate even if it was not consumed increased the relative risk of illness, thus suggesting that other food items may have been contaminated when they came into contact with it on the plate. This Salmonella outbreak highlighted the risks associated with the improper handling of food in private residences, which are then sold at a large public event.

Feral pig hunting: a risk factor for human brucellosis in north-west NSW?

A multi-agency investigation followed the notification of four locally acquired human brucellosis cases in north-west NSW. Feral pig hunting within a geographically discrete region was identified as the likely exposure with Brucella suis the suspected cause. To test whether feral pigs in the region were infected with Brucella, serological testing was performed on trapped feral pigs and testicular abscesses from condemned carcasses bound for export were cultured. Although no Brucella species were identified in the feral pigs tested in NSW, Leptospira species were. Strengthening of human surveillance and ongoing collaboration between animal and human health agencies is required to confirm that Brucella suis causes brucellosis in humans and feral pigs in north-west NSW.