Updated 12/4/12 as follows (accredited to http://www.vbschools.com/health/HeadLice.asp )
Virginia Beach City Public Schools: Head Lice Procedures
Head lice are small insects that can be found on the head, and live close to the human scalp. Head lice are not known to spread disease. Head lice have difficulty attaching firmly to smooth or slippery surfaces like plastic, metal, polished synthetic leathers and other similar materials. Head lice cannot hop or fly and are spread by direct contact with the hair of an infested person.
Identification of student with head lice infestation by the school nurse
A student is identified with head lice infestation when the school nurse has identified live lice on the student’s head, and/or nits are found within ¼ inch of the base of the hair shafts (scalp).
Contact your school nurse if you have any additional questions or concerns.