Three students in the Sanford school system have contracted viral meningitis, according to a letter that went out to parents on Tuesday.

One student at Sanford Junior High and two at Sanford High School were confirmed to have the illness, said David Theoharides, superintendent of schools, in the letter dated Sept. 29.

The custodial staff at the Sanford School Department is disinfecting bathrooms, faucets, drinking fountains, desks and the cafeteria, the letter said. Students were also encouraged to take precautions themselves by washing hands often with soap and water after using the bathroom, coughing or blowing their noses.

Seven previous cases of viral meningitis have been reported in three York County school districts this fall. One was reported in Yarmouth on Wednesday. No cases of bacterial meningitis, a more serious form, have been reported.

Viral meningitis is the most common type. Most people recover without treatment. Symptoms may include fever, headache, stiff neck, sensitivity to bright light, sleepiness, vomiting, lack of appetite or lethargy.