Like many in childcare, Nathanael Cachia contracted hand, foot and mouth disease when he was 16 months old. The doctor told his mother Caileen that it was a mild illness and to just keep him quarantined until it cleared.
By the next day, Nathanael was paralysed in his right leg.
"He was incredibly miserable, vomiting and inconsolable," Mrs Cachia said. "We went to the emergency department and they found he had brain inflammation. It took them 12 hours to figure out he had an enterovirus."
Now a healthy seven-year-old, Nathanael still receives physiotherapy for his leg, which has almost regained full strength.
Enterovirus is common in Australia, and is a cause of the usually mild hand, foot and mouth disease. But Nathanael was found to have the rarer EV71, responsible for the deaths of two NSW children since late last year, and suspected in the deaths of two more. Two of the children were under the age of one; three were from metropolitan Sydney and the other from the Hunter region.
"It made me feel sick and so sad when I heard children had died recently from this," Mrs Cachia said. "I realise we were lucky. I would urge parents to take their children out of childcare if they have hand, foot and mouth disease and to go back to the doctor if their child gets worse."
A spokeswoman for the NSW Ministry of Health said the latest data provided through NSW Health's surveillance system showed the incidence of enterovirus cases had dropped since March.
"We have sent alerts across the state, including media releases for the general public and targeted messages to general practitioners, emergency departments and childcare centres," she said.
There are no plans to make enterovirus a notifiable disease, whereby doctors are required to alert health departments.
"The reasons for making a disease notifiable include two main criteria: whether we can prevent further spread from an individual case by public health action, and whether we can gather data about each case to contribute to a better understanding of how to prevent it in the absence of alternative methods," the spokeswoman said.
"Hand, foot and mouth disease and enterovirus do not meet these criteria."
Bruce Thorley, of the Victorian Infectious Diseases Reference Laboratory, stressed that in most cases EV71 caused no symptoms or did not progress beyond hand, foot and mouth disease. "These hospitalisations and deaths are very severe cases," he said.
His laboratory had been notified of children admitted to hospital with paralysis and neurological symptoms, who are then tested to exclude polio. Though eliminated in Australia, polio may be imported from overseas.
"In excluding polio from these cases, we found they had a specific strain of EV71, called C4a," he said. "I don't think we need to be alarmed, but we do need to be aware this strain is present."