Those at high-risk of contracting the 'flu virus have been urged to obtain vaccinations after the number of cases reported more than doubled.
The National Disease Surveillance Centre (NDSC) said this evening the number of cases of influenza-like illness (ILI) had risen to an estimated 70 cases for every 100,000 over the past week.
NDSC clinical microbiologist Dr Robert Cunney said this has seen the highest rate reported in Ireland for this time of year since influenza surveillance began in 2000.
There are three main types of the virus, A, B or C. Influenza A is the most serious, Dr Cunney said. The main strain circulating here is an influenza A (H3N2) or Fujian-like strain, which has also hit Britain and other European countries.
The strain is slightly different to the Panama-type strain that has circulated over the past few years, but the current 'flu vaccine is considered to offer some protection against the Fujian-like strain and other types of the virus in circulation.
"The symptoms of influenza infection usually develop over a matter of a few hours and include a high temperature, sore muscles, dry cough, headache and sore throat. This is different from the common cold, which tends to come on more gradually and usually includes a runny nose and a normal temperature," said Dr Cunney.
In Britain, there have been six reported deaths due to influenza A in children in the past two months. The NDSC said it is not known if this represents a genuine increase in deaths from influenza, as it may be related to new technologies that are used to detect the virus.
"No deaths from influenza have been reported in Ireland, despite high levels of influenza activity, two large outbreaks in schools and the use of the same new technologies for influenza detection here," Dr Cunney explained.
Those most at risk include the over 65s, people with severe illness such as chronic heart disease, chronic lung disease and diabetes, those with lower immunity due to disease or treatment, children or teenagers on long-term aspirin therapy, residents of nursing homes, old people's homes and other long stay facilities and healthcare workers.
The Minister for Health, Mr Martin, today met with officials from the NDSC and the Irish Medicines Board to discuss what further measures may be needed.
He said his department has written to all health board chief executives asking them to advise GPs and accident and emergency Departments of the current situation. The NDSC will also provide GPs with technical advice.