There have been 3,538 laboratory confirmed Norovirus infections in the United Kingdom this fall and winter, according to new figures from the Health Protection Agency. This number marks an 83 percent increase from the number of cases recorded over the same time period last year, says the group. Almost 500 of this year’s cases occurred in the week leading up to Christmas, said HPA in its report, released Friday. In the two weeks prior to December 23, a full 70 hospital outbreaks were recorded. Authorities say that the number of reported cases points to an even larger number of actual illnesses, since most go unreported. For every Norovirus case that is diagnosed, UK health officials estimate that 288 more go unreported. That means that over a million people are estimated to have been sickened by the virus this season. The UK is not the only place where an uptick in Norovirus has been noted. Europe and Japan report that Norovirus rates were higher earlier in the season this year. Australia says its Norovirus season, which usually peaks in the winter, is lasting longer this year. Norovirus is a highly contagious pathogen that travels via the fecal oral route. Norovirus infections can be contracted through contact with contaminated individuals, surfaces or food. The virus travels quickly in enclosed spaces such as hospitals or cruise ships. Symptoms of Norovirus infection usually appear one to two days after exposure, and include diarrhea, vomiting and abdominal cramping. The disease usually resolves itself in one to three days, but illness can be more severe in young children, older adults and those with compromised immune systems.