Canadian families should be cautious at petting zoos and farm fairs following an outbreak of a new swine flu south of the border, the Public Health Agency of Canada said.

In the U.S., more than 200 people, mostly children, have been infected by H3N2v since last month. Three people were hospitalized.

The virus is spread to humans, especially children, by handling and petting infected pigs.

"Many Canadian families visit agricultural fairs taking place at this time of year and may be exposed to this flu virus," the agency said in a release Monday.

The government said the new flu strain has not been detected in Canada, but warned it could eventually circulate here.

The H3N2 variant virus does not spread easily from person-to-person, the agency said.

Children younger than five are at a higher risk. The symptoms tend to be mild and include fever, cough, vomiting and diarrhea.

U.S. health officials say they are developing a vaccine to prevent the virus.
In 2009, the H1N1 swine flu became a worldwide pandemic that made millions sick.