The disease was proved to be encephalitis during laboratory test of the samples of the patients, Additional Secretary (Health) R P Ojha told reporters.
Meanwhile, the toll mounted to 200 with 137 deaths reported from the SKMCH and Kejriwal charitable hospitals in Muzaffurpur, he said.
Altogether 47 children died at the PMCH in Patna and 11 at the ANMCH, while five deaths were reported from different hospitals in Vaishali district, Ojha said.
Ten districts have been declared as encephalitis-affected districts and the leave applications of doctors in all these districts cancelled in view of outbreak of the disease, he said.