Ontario's H1N1 flu cases have nearly doubled from Sunday, increasing to 31, with cases now being reported from outside the GTA.

However, the 17 news cases are all of the mild variety, Dr. David Williams, the province's acting medical officer of health, told a Monday news conference in Toronto.

Of the 31 cases, 25 directly track back to Mexico, he said.

There is one case where the virus was passed from an infected person to a close family member. In five other cases, the patient's history has yet to be determined, Williams said.

In Toronto, a city of about 2.5 million people, the number of cases has increased to nine. Here are how the other cases are distributed:

  • York region - 7
  • Durham region - 6
  • Windsor-Essex - 4
  • Peel - 2
  • Oxford - 1
  • Simcoe-Muskoka - 1
  • Sudbury and district - 1

There are 11 males and 20 females affected. The ages of those affected range from four to 50.

Williams said Monday that health officials had given the new total as 16. However, two of those cases are being reassessed, which is why the new total is given as 31 and not 33.

As of July 1, 2008, Ontario's population was 12.9 million, according to Statistics Canada.

Nationally, there are 140 confirmed cases.

The biggest worry nationally is the case of a young Alberta girl who sick with a severe form of the flu. She has been hospitalized but is reportedly doing well. She has no known connection with anyone who has travelled to Mexico.

What to do

The symptoms of H1N1 flu (previously known as swine flu) are similar to other seasonal flus:

  • chills and cough followed by fever, loss of appetite, muscle aches and fatigue
  • runny nose, sneezing, watery eyes and throat irritation
  • Nausea, vomiting and diarrhea may occur in adults as well as in children
  • In severe cases, or in individuals with other medical problems, pneumonia can develop

"As always, in flu season, if you have signs and symptoms, you do the right thing," Williams said.

Health officials have the following advice for people to avoid spreading any flu-like virus:

  • Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it
  • Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective
  • Avoid touching your eyes, nose or mouth. Germs spread this way
  • Try to avoid close contact with sick people
  • Stay home from work or school and limit contact with others if you get sick

Williams said this particularly applies if a person has recently been to Mexico or has had contact with a confirmed case in the past seven days.

People who have recently been to Mexico but haven't shown any symptoms in the past seven days are okay to go to work, he said.

"I've been impressed with the responsibility people have taken in this regard," he said.

Those Ontarians who have general questions about H1N1 flu can call the ServiceOntario INFOline at 1-800-476-9708.

If someone has flu-like symptoms and believe they may have H1N1 flu, they should call Telehealth at 1-866-797-0000.

With a report from CTV Toronto's Reshmi Nair