An elementary school in Colonial Heights, VA is open again after an outbreak of gastrointestinal illness forced officials to shut it down.

About 150 students at Tussing Elementary School reported norovirus symptoms of stomach pains, nausea and vomiting last week.

Tussing Elementary has a student population of more than 600. The cause of the outbreak and how it was spread is unknown.

Principal David K. Staples wrote a letter to parents saying the closure “gives us an opportunity to thoroughly clean all surfaces in the school and apply all of our internal procedures to assure the cleanliness of the school.”

Staples also said food-safety procedures and cafeteria protocols are also being reviewed.

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