Four of the children including the two dead victims Parvez, 12, and Alamgir, 18, came from Goalando in Rajbari. Al Amin, 10, is the third dead victim and the only one from Manikganj town.

Alamgir's brother Tushar, 14, and another boy Suruj, 11, the two others from Goalondo, have been quarantined at the DMCH as the doctors failed to diagnose the disease.

A team of experts on communicable diseases have collected tissue samples from several other victims of the disease in Goalondo, the BBC Bangla Service reported yesterday.

Dr Jahangir Hossain of ICDDR,B (International Centre for Diarrhoeal Diseases Research, Bangladesh) and a member of the visiting team of experts said the samples will be sent to Atlanta, USA, for diagnosis at the Center for Disease Control (CDC) there, sources said.

"We haven't been able to identify the disease but we are sure it's viral," Dr Hossain told BBC last night.

He also did not rule out the possibility of contraction from local poultry or other farm animals, but said experts are unable to comment on the spread of the disease until CDC's diagnostic report is at hand.

Meanwhile, hospital authorities formed a medical board yesterday in connection with the mysterious illness.

Dr Md Abul Faiz of the hospital's medicine ward said symptoms of the illness include high fever, headache, tendency to vomit, diarrhoea and loss of consciousness.

He however ruled out malaria, meningitis or encephalitis.

A report from Rajbari says fear spiralled over the mysterious disease after the recent death of five of a family in Joran, the same village where four of the DMCH victims come from.