Four more children died at Kejriwal hospital, while another died at Srikrishna Medical College Hospital (SKMCH) here, official sources said.
Thirty-three children had died due to the fever in Muzaffarpur district till yesterday, the sources said.
A central team, which had collected blood samples of the patients to ascertain the cause of the death, said that it was clinically diagnosed that the children were suffering from encephalitis.
"We can say the reason for the death of children is encephalitis but, at this stage, it is difficult to say what sort of encephalitis it is, whether it is viral one or Japanese", Dr I P Choudhary, member of the central team, told reporters.
Another member, Dr B P Tambley of ICMI New Delhi, said it had been clinically established as cases of encephalitis caused by Culex mosquito which was found in the surroundings.
Eighteen children were still undergoing treatment at the two hospitals, they said.
