Another five people have been infected with E coli bacteria originating from animals at Brisbane's Ekka show.
There are now 40 confirmed cases of E coli infection.
Of these, 27 are children aged between one and 15.
The oldest person infected is 77.
Authorities say STEC genes that produce E coli were detected in the bedding of animals in the Ekka's nursery last month.
A Queensland Health spokesman said the number of cases are likely to increase as authorities wait for further samples to be tested.
Health authorities are also responding to an outbreak of highly contagious norovirus gastroenteritis in southeast Queensland and a measles outbreak along Australia's east coast.