Call for more research on norovirus risk
More money needs to be invested in wastewater treatment research so communities can prepare for the highly infectious stomach bug norovirus, a leading scientist says.
Graham McBride, principal scientist of water quality at Niwa, said not enough was known about the effects of the disease at different doses, or how it acted in water.
More information about how norovirus "aggregated" - or clumped when in water bodies - could be used for effective town planning, he said.
"We've spent a lot of money in the last 30-40 years on advanced waste treatment.
"If we treat human sewage well, we remove most of it before it can get to receiving water."
Norovirus can spread through contaminated water and food, person-to-person contact, or through the air.
The virus, which often occurs in outbreaks, can lead to nausea, vomiting and diarrhoea, stomach cramps and fevers.
McBride said that although the disease was a major cause of viral gastroenteritis worldwide - and outbreaks were often publicised - only recently has technology been available to enumerate its concentration in water.
"Until we know something about what response you get from given doses, you really aren't able to do sensible risk assessments."
McBride said two recent international clinical trails - using volunteers - have attempted to quantify dose response, but more needed to be done to quantify norovirus aggregation in water.
"Because norovirus has been found . . . to be the big issue with human sewage, we are doing risk assessments assuming that in all cases they are not aggregated.
"If they are aggregated, the risks will be lower than what we are calculating."
He said that information could be then be applied to town planning.