(CNN) As US health officials are becoming increasingly concerned about the impact of this year's flu season, nearly half the students at a Virginia high school were absent with flu-like and gastrointestinal symptoms this week, according to the school district.
"There are approximately 1,000 students absent with flu-like/gastrointestinal symptoms at Stafford High School. Our Health Services team is working with the local health department to identify the root cause of the illness," Sandra K. Osborn, chief communications officer with Stafford County Public Schools, said in a statement.
Stafford High School, located in northern Virginia in the city of Fredericksburg, has an approximate enrollment of 2,100 students, Osborn said.
School activities scheduled through the weekend have been postponed, according to a message on the Stafford High School website.
"Due to the high number of student and staff illnesses reported this week, all Stafford High School activities and athletics scheduled through Sunday, October 23, are canceled. We will reassess conditions on Monday and provide you with further information," the message read.
CNN has reached out to Stafford County Public Schools and the county health department for further information.
An early increase in seasonal flu activity has been reported in most of the US, with the nation's southeast and south-central regions reporting the highest levels of flu as of last week, according to the US Centers for Disease Control and Prevention.
School districts elsewhere in the US have also reported an uptick in flu-like symptoms among students. At least two high schools in the San Diego Unified School District had high rates of absences last week, with one school recording about 1,000 absences out of 2,600 students, a school spokesperson told CNN.
Flu activity in the US often starts to increase in October and usually peaks between December and February.