Violent diarrhea bug dubbed ‘Ferrari of viruses’ is hitting Americans in record numbers… is YOUR state a hotspot?
Norovirus – dubbed the ‘Ferrari of viruses’ due to its rampant spread – is experiencing its biggest surge in more than a decade.
CDC data shows the infection, which causes severe diarrhea, vomiting and stomach pain, caused nearly 100 outbreaks in the first week of December, the last week available, with more people sick this time of year than since 2010.
One in four swabs for the virus also came back positive, the data showed, almost double the level last year in the same period.
The norovirus explosion is likely caused by a newly mutated variant of the virus.
But some also suggested that the surge could be linked to lockdowns, which prevented people from being exposed to the common virus for years, potentially weakening their immunity.
Other countries in the Northern Hemisphere are also reporting a rise, including Britain, where cases rose 40 percent from the same time last year.
It comes amid warnings of a quadruple onslaught of viruses hitting the US as millions return from the Christmas holidays, and amid concerns about a disease outbreak in China that has alarmed residents.
The above map shows reported norovirus outbreaks by state in the first week of December last year, according to the most recent data available
Overall, data showed that the US recorded 91 norovirus outbreaks in the first week of December – 40 percent more than the record for the same week from 2010 to 2024.
Across the US, Wisconsin reported the most norovirus outbreaks – or where two or more cases were reported in hospitals or schools – with a total of 22.
Ohio (11), Virginia (6), California (5), Oregon (4) and Vermont (4) also recorded a higher number of outbreaks compared to other states.
About 21 million Americans become infected with the virus each year, and about 2 million of these are sent to doctors’ offices or emergency rooms.
The disease is spread through contact with germs from an infected person’s vomit or feces, contaminated food, shared utensils, or surfaces they have touched.
Although most people recover within a few days, the virus kills about 900 people every year, mostly adults 65 and older.
Outbreaks are most common in winter due to an increase in the number of people gathering in groups for holiday festivities, traveling and staying warm indoors, where pathogens can easily spread.
Symptoms of norovirus – nausea, vomiting and diarrhea – occur quickly, within 12 to 48 hours after exposure.
Doctors say the disease can be prevented by washing your hands thoroughly with soap and water for at least 20 seconds, washing produce before eating it, disinfecting countertops, avoiding people who are contaminated, and cooking seafood at at least 145 degrees.
The graph above shows the increase in the number of positive norovirus tests from August 2024 through the first week of January 2025
Data on norovirus outbreaks came from CalciNetthe CDC’s National Norovirus Surveillance Network that tracks the virus nationwide using data from 34 labs in 29 states. Labs that are not part of the network can also supply data.
Separate data from the National Respiratory and Enteric Virus Surveillance System (NREVSS) – which receives data from 340 laboratories in 50 states – also revealed an increase in norovirus cases.
It showed that 28 percent of swab tests – or 828 of almost 3,000 tests carried out – detected the virus in the first week of January, equivalent to one in four detecting the virus.
This was nine percent more than the previous week, when 25.6 percent of swabs were positive, and 31 percent compared to two weeks ago, when 21.36 percent detected the virus.
By region, the data showed that Region 2 – which includes Missouri, Minnesota, Illinois, Michigan and Wisconsin – had the highest percentage of viruses testing positive at 29.89 percent.
By comparison, Region 1 – the southern US – had the lowest number of positive tests detecting the virus at 14.63 percent.
Dr. Lisa Lindesmith, an epidemiologist at the University of North Carolina, explained Science: ‘The initial data for the first part of the season certainly supports that we’re going to have a pretty intense norovirus year.’
Surveillance showed that a new variant called GII.17 – which has been present for years, but at a low level – has increased dramatically recently.
Norovirus researcher Miranda de Graaf, from the Erasmus Medical Center in the Netherlands, says the variant found there has undergone significant mutations.