Health officials now know that at least 141 people got sick after visiting This Old Barn restaurant. (Google Maps)

The number of people now known to have got sick after visiting a rural Thunder Bay restaurant last weekend has climbed to 141. That's up 15 from Thursday.

The Thunder Bay District Health Unit is investigating whether a norovirus caused the outbreak.

The virus has turned up in lab work done on two people who attended the Mother's Day buffet at This Old Barn.

Food and water samples from the restaurant are being processed by Public Health Ontario laboratories in Thunder Bay and Toronto, and in a Health Canada lab in Ottawa.

The labs are trying to match the norovirus that was found in the samples taken from the two patients.

Norovirus infections are characterized by a sudden onset of diarrhea and nausea. The illness is usually short-lived, with symptoms lasting on average 24 hours.

The virus is commonly attributed to outbreaks in institutions, holiday resorts and mass gatherings.

The Thunder Bay District Health Unit says it is generally spread to people through contaminated food or from contaminated surfaces such as door handles and light switches, then by hand-to-mouth actions.

Restaurant owner apologizes

Michael Ellchook, the owner of This Old Barn, has apologized to all those who got sick. He said he has operated the restaurant for 17 years, and has never before had a problem like this.

He said he hopes to reopen soon.

"I do business [all over the area], catering weddings almost as far as Upsala, and toward the border, and out to Pass Lake, and I've never had this problem.

"I feel bad for everybody that was sick. I very much apologize for all that. But I hope to see them again another day."

The health unit became aware of the situation after being contacted by emergency-room staff the Thunder Bay Regional Health Sciences Centre, where 12 people were admitted.