gastro strain could be next pandemic

Pandemic fears over new gastro strain, discovered in Victoria

Rania Spooner

A new strain of the virus that causes gastro has been identified in Victoria, and the researchers behind the discovery warn it could soon become an epidemic, or even a pandemic.

This strain of norovirus - the most common cause of gastroenteritis - was first detected at a very low frequency in Victoria in August last year but reappeared slightly altered in June. Experts fear this slight change means it could skip around herd immunity.

It is believed to have been responsible for most gastro outbreaks in the state since, sparking a health department warning earlier this month.

Using 14 years of surveillance data from Victoria, the scientists who made the discovery say this strain has the potential to become a pandemic in two to seven months.

Gastro often involves acute nausea, vomiting and diarrhoea, transmitted through coming into contact with infected faeces or vomit, person-to-person, through contaminated food or water, or touching a contaminated surface, like a toilet.

The discovery was made by the Royal Melbourne Hospital's Victorian Infectious Diseases Reference Laboratory at the Doherty Institute, and will be published today in the European journal Eurosurveillance.

"If this new recombinant has undergone enough change to escape herd immunity and become the next epidemic variant, then from its first detection in Victoria in mid-June 2016, the expected epidemic could be any time between mid-August 2016 and January 2017," the researchers wrote.

"The strain has already become predominant between norovirus seasons in outbreaks in Victoria, Australia, over the past three months (July to September).

"On this basis, we propose it as a candidate new epidemic strain. If past trends are followed, then it would have the potential to also predominate in other parts of the world."

Dr Mike Catton, the director of the laboratory, said: "Based on years of experience monitoring new norovirus strains we think that this new strain is genetically different enough to cause an epidemic".

Victoria's chief health officer Professor Charles Guest issued a warning about the new strain to hospitals, aged and disability care homes and child care centres earlier this month.

"As is common with many viruses, norovirus can mutate (change) and, through routine surveillance from our public health laboratories, we know it does so frequently," he said.

Occasionally the virus changes to become so different that the community has no effective immunity.

"This means that everyone who comes into contact with it is very susceptible to illness; whether contact is with faeces of an infected person or by being close to an infected person who is vomiting."

Those most at risk are children under five, adults aged over 65 and people already with compromised immune systems.

The full health department advisory is available here.

https://www2.health.vic.gov.au/about/news-and-events/healthalerts/new-strain-of-norovirus-detected-in-victoria

http://www.theage.com.au/victoria/pandemic-fears-over-new-gastro-strain-discovered-in-vic-20160929-grrm52.html