Prime Minister Stephen Harper said Thursday he is "very concerned" about the spread of H1N1, especially among native groups in Manitoba.
The prime minister said the virus continues to confound health experts.
"We really don't know why the H1N1 is more severe among some populations, rather than others," Harper said in Halifax.
He mentioned similar patterns in Mexico where the virus originated, noting that "some populations seemed to be significantly more vulnerable than others."
Harper said he's spoken with his minister of health about the situation, and said the department of health is working with the communities affected to try and address the situation.
Health officials in Manitoba have confirmed almost 460 cases of H1N1, with more than one quarter of those from remote northern communities.
Native leaders are demanding the federal government do more.
"There needs to be an organized plan," said Ron Evans, Grand Chief of the Assembly of Manitoba Chiefs. "Someone needs to be responsible. Right now, no one wants to accept responsibility for the First Nations."
Manitoba aboriginal leaders declared a state of emergency in their communities because of H1N1.
That allows reserves to redirect funds from other programs to help fight the flu virus.
Some are calling for the army to be sent in.
"We need help," said Chief David Harper of the Garden Hill First Nation, "if Canadian Forces are being sent all over the whole world to help out, why not in our communities?"
"Most of the First Nations that are in Manitoba are not even prepared. They don't even have sanitizers," Chief Harper said.
That issue hit the headlines this week when it was revealed Health Canada hesitated in sending hand sanitizers to flu-stricken reserves because they contained alcohol.
Nationally, the death toll from swine flu rose to 21. A 68 year old man from Durham Region, east of Toronto, died after testing positive for the H1N1 flu virus.
