VANCOUVER, Wash. (AP) — Dozens of students are out sick at several Vancouver Public Schools elementary schools, prompting cleaning, disinfecting and a letter to parents warning them of the symptoms of the stomach flu.

The Columbian reports at Harry S. Truman Elementary School, 72 of the school’s approximately 520 students were out Wednesday, 61 on Tuesday and 82 Monday. Students have fever, coughing and flu-like symptoms, district spokeswoman Pat Nuzzo said.

Some students also had vomiting and diarrhea, symptoms of viral gastroenteritis, prompting the district to send a letter to parents. District staff are advising that parents keep ill children at home until they’re well for a full 24 hours. District maintenance staff cleaned and disinfected the school Tuesday.

Additionally, more than 50 Washington Elementary School students were out sick Wednesday. That campus was to be cleaned and disinfected Wednesday. Nuzzo said the district is also monitoring Harney Elementary School where 40 students were out sick Wednesday.

KCPQ-TV reports that Seattle’s Leschi Elementary will be closed Friday for cleaning because of a possible Norovirus outbreak. Over 100 students and staff members reported being sick Thursday, according to Seattle Public Schools.