VALLEJO (CBS SF) -- School officials in the Bay Area on Friday were still scrambling to contain a norovirus outbreak that has left hundreds of students sick.
It's unusual for the virus to be spreading so fast.
For the past three days, Chris and Monika Trout have been monitoring a virus that's running through their Vallejo family like wildfire.
"They got sick on Wednesday, Thursday and Friday," said Chris Trout.
"Sleeping all day. I give them liquids water to keep them hydrated or Popsicles because they won't eat," said his wife.
She is concerned it may be the norovirus that spreading through the South Bay at an alarming rate in the past week.
The San Jose Unified School District confirms it has 424 current cases of norovirus, with 56 new cases reported just Thursday. 18 schools have been affected. Roughly 1,000 cases were reported in Yolo County this week.
"We are seeing a significant increase and it's an unusual amount of cases this year," said Dr. George Han with Santa Clara County Public Health.
Han said it is unusual to see this many cases, especially at this time of the year.
"Norovirus is a seasonal virus. During colder winter months, it comes out more," said Han.
It's spread through ingestion. Once infected, individuals are contagious for 48 hours after their symptoms go away.
Public health officials warn that hand sanitizers do not work against norovirus.
They say you should instead wash your hands for at least 20 seconds with antibacterial soap and warm water.
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