Rising cases of swine flu in NZ

New Zealand is experiencing rising levels of swine flu infection with nine deaths this year linked to the virus, including three in the past three days, health officials said on Thursday.

In 2009, the nation's Ministry of Health reported a total of 35 deaths from swine flu in New Zealand - the first country in the Asia-South Pacific region to record an outbreak of the deadly virus that became a worldwide pandemic last year.

Although World Health Organization Director-General Margaret Chan announced on August 10 that the H1N1 influenza virus has moved into the post-pandemic period, New Zealand's winter has seen a second wave of the virus.

"Influenza H1N1 activity is continuing to increase," New Zealand deputy director of public health, Dr Darren Hunt, said on Thursday.

More than 450 people have been hospitalised with laboratory-confirmed cases of the virus this year in New Zealand, and 67 required treatment in intensive care units, he said.

"Pandemic influenza H1N1 is the most common strain of influenza circulating in the community," he said in a statement that updated the death toll to nine.

For most people, it's a mild to moderate illness, he said - but for some, it can be serious.

Reports from across the country showed widely differing levels of infection, with some badly affected provincial areas reporting hundreds of schoolchildren absent with influenza illness.

Many of these areas had suffered little impact from the virus last year, Hunt said.

New Zealand has carried out a national program of antiviral vaccination since December. Antivirals are free for those suffering from influenza, Hunt said.

In April 2009, New Zealand confirmed swine flu among a school group that had recently returned from Mexico, extending the deadly new disease's global reach into the Asia-South Pacific region.

After that initial infection, thousands of New Zealanders developed swine flu, though it turned out to be less deadly than first feared.

Most of the deaths occurred when patients had pre-existing medical conditions that included some factor that lowered their resistance to the disease, Chief Coroner Neil MacLean said at the time.