Two members of a family died under unclear circumstances and three others fell sick in the last two days at Songaon village in Baliadangi upazila, creating panic among locals.
Mina Begum, 35, wife of Hafizul Islam fell sick suddenly on Friday night and died within a few minutes.
Poshina Begum, wife of Hafizul's elder brother Hazirul, fell sick on Saturday night. She was taken to Baliadangi Upazila Health Complex and given primary treatment.
"She died at home on Sunday night," said doctor Md Mahfuzur Rahman Sarker, civil surgeon of the district.
Hafizul's daughter Tanzina Akhter, mother Hazera Khatun and Aleya Akhter have also fallen sick.
The civil surgeon said that a team visited the village after learning about the deaths but the reason could not be confirmed yet.
A team of Institute of Epidemiology Disease Control and Research (IEDCR) is scheduled to visit the village later in the day.
Besides, upazila health department held a meeting with villagers on Sunday and asked them to exercise caution.
Earlier in 2018, five members of a family died from Nipah Virus in the upazila.