Meanwhile, at least 119 students of different schools in Narayanganj, Gazipur, Jhenidah, Natore and Bagerhat became sick. Expert physicians said since it was not a disease, the students were provided with anxiolytic medicines.

A group of psychiatrists led by Prof Enayet Karim went to Narsingdi to probe the phenomenon and prepare a report to be submitted to the director general of health.

While talking to The Daily Star experts said "mass hysteria" is a psychological disease that mostly strikes teenagers and females. It does not have any long-term effect and the students and their guardians need not be panicked.

As the psychological defence mechanisms in teenagers are not developed, sometimes they feel quite vulnerable. They could have headaches, convulsions and fever. Girls may suffer the most for biological and social reasons, the expert said.

"As no pathological evidence was found, people should not be terrified of the symptoms," said Directorate General of Health Shahjahan Biswas.

Motivation and awareness building is more important than anxiolytic medicines, he said adding that there are trained physicians in every district of the country and they could call for teams from the capital if needed.

Girls are mostly affected, as females of certain ages are more hysteria prone, Parvez Chowdhury psychiatrist of the National Institute for Mental Health said.

He, however, blamed the bandwagon effect. When students hear about the disease, many of them start thinking they could be affect by it. Sometimes without any fathomable reasons, they start feeling that they have become a victim of the "mysterious disease". "If someone becomes sick, others might be affected just by watching him or her. So the sick should be treated separately," said the psychiatrist.

He recalled the fuss about insects in Dholkolmi plants and the Jhin Jhin disease that created panic in the previous two decades. If the media did not cover the incident, the spread of the disease would slowdown to some extent, he added.

The Ministry of Health will organise a press conference today [Thursday] to explain the reasons for the illness of students.

Meanwhile, a total of 119 students of different schools of the country became fresh victims of the disease.

In Narayanganj, 38 students and a teacher of Adarsha High School of Mithabo in Rupganj upazila became unconscious in the morning.

Of them, 16 were taken to Dhaka Medical College Hospital (DMCH) while the rest were admitted to Bhulta Health Complex and Rupganj General Hospital.

Currently, a total of 30 students of different schools of Narsingdi, Manikganj and Narayanganj are undergoing treatment at DMCH.

In Natore, 42 students, including a boy, of Bahimali High School in Boraigram upazila fell unconscious yesterday. Thirty-eight of them were admitted to local hospitals, UNB reports.

On information, a team of army medical corps, led by Major Mahfuzur Rahman, visited to the spot and inquired about the health condition of the students.

In Gazipur, 11 students of different classes of Malek Chowdhury Memorial Girls' High School in Kaliakoir upazila became unconscious yesterday morning.

Of them, six were admitted to Kaliakoir Upazila Health Complex while the others were released soon after they were taken there.

In Bagerhat, 19 students of Bagerhat Government High School became unconscious yesterday noon.

They were admitted to Bagerhat Sadar Hospital. One of them was later moved to Khulna for treatment. A three-member medical team was formed to provide proper treatment to the ailing students.

Our Jhenidah correspondent reports: Nine female students became unconscious in Kaluhati Secondary School in Jhenidah. Students of the whole school became panicked following the incidents.