More than 70 students were out of class Monday at Ithan Elementary school in Radnor Township, Delaware County.
School administrators are worried that it may be the flu. Many of the sick kids have similar, influenza-like symptoms.
"Please, if your child has any of these symptoms, keep them home so they do not infect other children. These symptoms include fever, cough, sore throat, body aches, headaches, chills, fatigue and possible diarrhea and vomiting," Superintendent Linda Grobman said in a letter posted on the school's Web site.
The school is taking extra precautions. The building has been sanitized and administrators are in contact with the state health department and the district also posted Swine Flu facts on the school's Web site.
"We are advised by the Department of Health that there is no surge of flu in Delaware County, and we want to make sure our schools remain healthy," Grobman reassured parents in her letter.
Philadelphia announced it's first Swine Flu death Monday. In the state of Pennsylvania, there are now a total of two Swine Flu deaths. A Berks County woman died last week.