Lambton Public Health (LPH) is advising of a potential measles exposure site in Sarnia.
The health unit said the potential exposure was at the Bethel Pentecostal Church on London Line on Friday, March 21 between 7 p.m. and 10 p.m.
LPH is working to identify known contacts who may have been exposed to the virus.
Officials said this latest exposure is not connected to either of the previously reported lab-confirmed measles cases in Lambton County.
LPH said anyone who may have been exposed at the London Line church should contact the health unit at 519-383-8331 if you have a severely weakened immune system, are pregnant and not protected against measles, were born in or after 1970 and unvaccinated or have only received one dose of the measles vaccine.
Exposed contacts are advised to monitor for symptoms such as a fever, red eyes, cough and a rash, which can appear for up to 21 days after.
If you develop symptoms you're urged to contact your health care provider and self-isolate at home.
You can also visit Lambton Public's Health website for more information about the virus and appropriate precautions to take.