District civil surgeon Doctor Md Abdul Momen confirmed the matter on Sunday.
The DC office staff is CA Md Dulal Hossai while two others are residents of Lohagara upazila.
With these three new cases, total cases in the district rose to nine. Among them, there are four physicians, he added.
The civil surgeon said that till now total 192 samples have been sent to Jashore for test. Among them, they received results of 91 samples from where nine tested positive.
Earlier, the district reported its first coronavirus patient to have completed recovery.