Lambton Public Health has reported one new case of COVID-19 in Sarnia-Lambton, bringing the total case count up to 369.
An update from the health unit posted on Sunday night shows that there are now seven active cases.
To date, 337 cases have been marked as resolved in the region, and the number of deaths related to COVID-19 remains at 25.
There are still two outbreaks that had previously been identified at Twin Lakes Terrace and an unnamed workplace.
Meanwhile, the province reported 1,042 new cases of COVID-19 on Sunday, the highest daily increase reported in Ontario so far.
Health Minister Christine Elliot said 309 of the new cases were in Toronto, 289 in Peel, 117 in York Region, 80 in Ottawa, and 52 in Durham.
Elliot also said 736 more cases in Ontario were marked as resolved on Sunday.