A new strain of norovirus, known as GII.17[P17], has taken over most outbreaks across the US, according to data from the Centers for Disease Control and Prevention (CDC). The emergence of this strain may be behind the recent surge in stomach bugs nationwide. Scientists say it’s too early to determine if this strain is causing more severe norovirus disease or if lower population immunity is the reason for the increase.
Historically, previous waves of norovirus in the US have been dominated by a different strain called GII.4. However, this season, only 7% of outbreaks are linked to that strain. The CDC has tracked at least six cruise ship outbreaks and many cases resolve on their own without treatment. Data suggests that norovirus rates are at peak levels across the country.
Researchers say that while versions of GII.17 have circulated for decades, this recent surge is unusual. Some parts of Europe experienced a sudden rise in cases last year, and Japan and China reported their first waves after 2014. To determine if GII.17 is causing more severe norovirus cases, additional studies are needed.
Experts caution that data on norovirus cases still has gaps around the world and that more research is required to prove any potential increase in illnesses caused by the strain.
Source: https://www.cbsnews.com/news/new-norovirus-strain-us-wave-stomach-bug