HUS is triggered by a type of bacteria called STEC, which can move from animals to people and produce a dangerous toxin.

Victoria's Deputy Chief Health Officer Clare Looker told reporters that cases where STEC infection progresses to HUS are "very, very rare" and that the state usually records only one to five such cases each year.

So far this year Victoria has logged two HUS cases, but investigators have not found a common source and no single facility has been linked to both infections.

Dr Looker explained that STEC bacteria are found in many farm animals, yet the step from infection to severe HUS happens only in a tiny fraction of people; therefore closing one farm would not eliminate the risk for children or the wider community.

Health officials continue to urge Victorians to wash their hands after any contact with animals, and they monitor STEC detections closely to spot any rise in risk.