Alarm as swine flu becomes dominant

Swine flu, which has killed at least six people so far, is now the dominant strain in New Zealand, scientists say.

Environmental Science and Research virologist Sue Huang, head of the national influenza centre in Upper Hutt, said the new influenza A H1N1 virus was the most contagious bug she had seen.

"The speed at which it has replaced seasonal influenza as the predominant strain just within the last week is incredible ... it's quite alarming."

ESR's latest surveillance report for the week ending Sunday shows swine flu accounted for about 75 per cent of all confirmed flu cases nationwide double the percentage of the week before. Wellington, Taupo and Rotorua regions were hardest hit. GP clinics are under pressure, with more than three times as many patients with influenza-like illnesses as at the same time last year.

She said it was impossible to predict exactly when the pandemic would peak but the fact the northern hemisphere had not even started its seasonal flu season yet suggested the virus could persist for some time.

Fortunately, it had not yet mutated and was not yet resistant to the antiviral drug Tamiflu.

"In all the cases where people have become seriously ill, it seems to be related to the individual rather than the virus."

Internationally, there have been three cases of Tamiflu-resistant swine flu in Denmark, Japan and Hong Kong.

GPs have been given the go-ahead to make phone assessments of patients who suspect they may have swine flu, and provide a written medical certificate for someone else to collect on their behalf.

A Massey University scientist who has been researching the spread and virulence of swine flu says it was "never a benign flu".

Professor Mick Roberts, a mathematical biologist at the university's Institute of Information and Mathematical Sciences, said the death rate could be "about the same or slightly higher" than from ordinary seasonal influenza, which kills about 400 people a year.

Early reports of low death rates in Canada and the United States could have made people "nonchalant" about the seriousness of swine flu. Comparing the number of confirmed cases and deaths in the US, Canada and Mexico in April and May, his team found the death rates were similar.

THE STATS

*Six deaths of people confirmed to have swine flu test results are awaited on a seventh dead person.

*Total number of confirmed cases yesterday 1555, up from 1431 the day before.

*As of last Sunday, 162 people had been admitted to hospital, 29 with pneumonia and five with acute respiratory distress syndrome.

- © Fairfax NZ News