At least 250 people attending a convention for school principals last week in Brisbane, Australia, were reportedly sickened with a foodborne illness and 24 were hospitalized.

Dr. Jeannette Young of Queensland Health said the conference participants had fallen ill after returning home, so the total number of those reported as hospitalized and their individual conditions would vary.

The Brisbane Convention and Exhibition Centre in Brisbane, Queensland, Australia.

Young said that health officials were working through the varied menus served at the Brisbane Convention and Exhibition Centre and checking with those sickened to see if they had eaten elsewhere while attending the conference. She reportedly confirmed that a chicken curry was under investigation.

“The usual causes for Salmonella infections are poorly cooked meat, poultry and eggs,” Young said, adding, “Of course, you can get transmission person to person, but given there are so many people unwell, we think it’s probably related to the food they all shared.”

She noted this was one of the largest foodborne illness outbreaks to have occurred in Queensland, which usually has about 4,000 Salmonella cases each year.

The convention center’s general manager, Bob O’Keeffe, said that a thorough investigation of the facility was being done, and that a full safety audit, including supplier facilities and systems, had been completed last year. “We are looking deep into our supply chain to see if there is any possibility that food supplied to the centre was the cause,” O’Keeffe said. He said the convention center had suspended the supply of fresh eggs and poultry products as a precautionary measure until the health investigation results were available. Officials said they expected the investigation to be completed within two days. About 1,200 delegates from schools across Queensland, plus education department officials, had attended the conference held Feb. 26-27 at the Brisbane Convention and Exhibition Centre. Brisbane is a city of about 2 million on the Gold (Pacific) Coast of Australia about 10 hours north of Sydney. Most people infected with Salmonella bacteria develop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most people recover without treatment. However, in some people the diarrhea may be so severe that they need to be hospitalized. In these patients, the Salmonella infection may spread from the intestines to the bloodstream, and then to other body sites and can cause death unless the person is treated promptly with antibiotics. The elderly, infants, and those with impaired immune systems are more likely to have a severe illness.