16 Sep Three new noroviruses cause gastro outbreaks across Australia
UNSW scientists have identified three new strains of highly contagious norovirus that are responsible for a major new epidemic of viral gastroenteritis that has affected hundreds of thousands of Australians over winter.
Scores of outbreaks of nausea, vomiting and diarrhoea have occurred in Sydney, the Hunter region and the ACT, mainly in closed settings including aged care facilities, hospitals, childcare centres and cruise ships. More cases are expected.
In 2012, Professor Peter White and his team in the UNSW Faculty of Science discovered a new strain of norovirus named Sydney 2012, which caused a worldwide pandemic of gastro, including major outbreaks in Australia.
This strain dominated cases of norovirus infection until this year, when it declined from 75 per cent of cases to 18 per cent of cases in Australia. Similar trends have also been seen in the US and New Zealand.
“Now that Sydney 2012 has declined, three new strains of norovirus have emerged as a new major health concern,” says Professor White.
“They are responsible for a big increase in the number of gastro cases in Australia in the past two months, and this new spate of infection is likely to continue to cause a wave of sick leave that will affect businesses and schools already reeling from the effects of the current influenza epidemic.”
UNSW PhD student and molecular virologist Jennifer Lun worked out the genetic typing of the new viral strains.
“I was surprised to find three new viruses, rather than a single one,” she says.
“Two of the viruses are hybrid strains that evolved from the previous pandemic Sydney 2012 strain, while the other new strain is likely to have come from Asia. It occurred to me immediately that there was a potential for them to cause an increase in outbreaks this winter, because people have not been exposed to them before.”