Araria civil surgeon B.K. Thakur said that while one child died Monday, there were others admitted to hospital with similar symptoms and who were in critical condition.
Last week, two children, a four-year-old and a six-year-old, died of the disease at Belwa panchayat near Araria town, officials said. Five children were earlier reported to have died in the district.
Araria district magistrate Ajay Kumar Choudhury said preventive measures have been taken on a war footing since last week, after five children succumbed to encephalitis.
A team of health experts from Patna visited the affected village in Araria three days ago, on a directive from Chief Minister Nitish Kumar, to oversee measures to check the spread of the disease.
Encephalitis is an acute inflammation of the brain resulting either from a viral infection or when the body's own immune system mistakenly attacks brain tissue. Children and elderly people, whose immunity is low, are especially prone to fall prey to the disease.
Till now, over three dozen children have died of encephalitis in the state this year.
Last year, the disease killed nearly 240 children in Muzaffarpur and Gaya districts of Bihar.