LONDON, ONT. -- There is a fifth COVID-19 case in London-Middlesex and the first case reported in Brant County is a Woodstock General Hospital employee.

The London-area woman in her 60s is self-isolating, but health officials still have not determined how she contracted the illness.

The Middlesex-London Health Unit says the woman has not travelled recently to an area affected by the virus and she has not had contact with any other confirmed or probable case.

They are continuing to investigate, and Dr. Alex Summers, MLHU associate medical officer of health, said in a statement they are expecting the number of local cases to continue to rise.

“Our staff are working diligently to follow up with this person’s close contacts and advising them to stay home for the next 14 days in an effort to reduce further potential spread of the virus...we’re asking the community to be vigilant.”

There's also a local connection to the first COVID-19 case reported in Brant County.

The Brant County Health Unit says the woman in her 40s got the virus during recent travel to Mexico. She returned home March 8.

The woman works at Woodstock General Hospital, and returned to work from March 9 to March 11, before she became symptomatic. She has since been in self-isolation with mild symptoms.

Health officials say the nature of the woman's duties at the hospital mean she had limited patient contact.

However, the Southwestern Public Health is in the process of notifying anyone she may have been in contact with.

The newest Grey-Bruce case, the third in the region, is a 61-year-old man who recently travelled to India. He is also in self-isolation after being discharged from hospital.

Public Health Grey Bruce says the man presented at a local hospital where all necessary precautions were taken and tests ordered. The health unit is investigating any additional close contacts he may have had.

Chatham-Kent also reported its first case on Wednesday.

Second positive case in Huron-Perth

A 57-year-old woman has been identified as Huron-Perth’s second case of COVID-19.

The Huron-Perth Health Unit says the woman isn’t showing any symptoms, and is self-isolating.

The health unit says the woman had close household contact with Huron-Perth’s first COVID-19 patient, a 64-year-old man from St.Marys, Ont.

That man is currently in critical condition in Stratford General Hospital.

The health unit says they are contacting everyone that has been in close physical contact with these two patients in the past few weeks.

So far, none of those people have tested positive for COVID-19.

- With files from CTV's Scott Miller