Doctors treating sick people at Kalyanpur Primary Health Center (PHC) said patients from Shantinagar village complained of sudden stomach ache, fever and vomiting.

Although doctors have not yet been able to identify the cause of the patients' illness, they suspect waterborne infection.

"The patients are under medical care and under observation. The health department will soon investigate the case in Shantinagar village," a doctor said.

Local BJP MLA Pinaki Das Chaudhary met the patients in the hospital.