FREMONT – Parents of Ellis School students were informed this week that one youngster there has been diagnosed with pertussis, also known as whooping cough.

A letter to parents said the illness is highly contagious.

Pertussis passes from person to person, but only if they are in close contact. Usual classroom contact of school-aged children is not considered close contact, said Beth Daly, epidemiologist with the New Hampshire Department of Health and Human Services.

People who have close contact with a carrier are urged to take antibiotics as a precaution, Daly said. DHHS works to identify those contacts after being notified of a case.

Over the past five years, the number of pertussis cases in the state has ranged from 48 to 227. Last year, 48 cases were reported. So far this year, 66 cases have been reported.

There is no outbreak of pertussis in the Fremont region, Daly said.

"It usually increases in the fall months," Daly said. "It spreads person to person, so we often see it in the school setting in this age group, which is why the vaccine is recommended for adolescents."

She said if parents have concerns, they should seek information from their health care provider, as the symptoms of pertussis can be similar to those of the flu virus. Principal Dawn Lewis could not be reached for comment.

A fact sheet on pertussis, including the symptoms, is available at the NH DHHS Web site, www.dhhs.state.nh.us.