ATLANTA (CP) - U.S. health officials confirmed Thursday that a Michigan infant has the West Nile virus and probably got it from the breast milk of his infected mother.

The child is healthy and his mother is recovering, the Centers for Disease Control and Prevention said. The CDC said it was virtually certain the virus came from breast milk, though there is no way to be completely sure. Doctors stressed that breast milk is the healthiest food for babies and that mothers shouldn't stop nursing because of West Nile fears.

Last week, when the case was being investigated, the CDC urged new mothers with the virus to talk to their doctor about whether to continue breastfeeding.

A spokeswoman for Health Canada said the department needs to look further at the issue of West Nile virus and breast milk in light of the CDC announcement.

"The chances of acquiring West Nile virus from breast milk are low, but it does require further study," said Paige Raymond Kovach.

"Health Canada keeps current of all West Nile virus transmission information to better inform the public and our partners."

She added the public should remember that the risks of being bitten by an infected mosquito in Canada remain low and that the risk of becoming sick after being bitten is low as well.

West Nile is rare in infants because they spend little time outdoors and the virus is usually spread by mosquito bites. Only four children younger than 12 months have been diagnosed with West Nile since it appeared in the United States in 1999. To date there have been no confirmed cases in children in Canada.

The 40-year-old Michigan mother gave birth Sept. 2, and received a blood transfusion that day and the next. She went home with her baby Sept. 4, only to be hospitalized on Sept. 17 for three days. Doctors later confirmed she had West Nile.

It's not clear how the mother became infected but it may have been from the blood, the CDC said. She and another patient, a liver transplant recipient, received blood from a common donor, and remaining blood samples from that donor show signs of contamination.

The government discovered last month that the virus apparently can be spread through blood transfusions, as well as organ transplants. The CDC reported 15 people this year have been diagnosed with West Nile virus within a month after receiving blood transfusions.

The virus is mostly spread through mosquito bites, and has infected 2,530 people in 32 U.S. states so far this year and killed 125, the CDC said.

So far in Canada there have been two confirmed deaths from West Nile. A 70-year-old man from Mississauga, Ont., succumbed to the disease last month, while in 1999 a 75-year-old man from Toronto died after being infected while visiting the United States.

There have been 11 confirmed cases of the disease in Canada this year and at least 36 Canadians are suspected of having the virus and are awaiting the results of tests being conducted in Winnipeg.

Most people bitten by an infected mosquito never get sick.