This year's influenza season has started, the European Influenza Surveillance Scheme (EISS) has said.

Increased influenza activity has been reported in five countries: Greece, the Netherlands, Northern Ireland, Spain and Switzerland.

Based on historical data, influenza activity is expected to increase in many more countries over the coming weeks, the government said yesterday.

It said the Disease Surveillance Unit within the Department of Public Health performs active surveillance of influenza, with a number of doctors reporting on the cases they see in their practice. This gives an indication of the influenza activity in Malta. Samples are also taken from the patients which are then tested to identify circulating strains.

From this system it was noted that the influenza activity in Malta started in the first week of January and so far the highest number of influenza cases has been reported in the last week of that month.

This year's season in Europe started about two weeks earlier than last year's, which had high levels of influenza virus detections in Europe from mid-February to late April. This year's cases to date have primarily been of the H3 strain of the more virulent influenza A virus.

Influenza is highly contagious and spreads rapidly by coughs and sneezes from people who are already carrying the virus. Influenza affects about one in 10 people around the world every year, creating substantial demands on health care resources and escalating costs due to increases in primary care consultations, hospitalisation, clinical complications, drug treatment and absence from work.

The most common symptoms of influenza include an abrupt onset of fever, headache, muscle ache and a dry cough. The effects of influenza are debilitating, putting people out of action altogether, and recovery can take up to two weeks. Anyone can get the flu and it can be especially serious for the elderly, children and people with certain medical conditions (commonly defined as high-risk people).

To reduce the risk of infection, the public should take general health precautions and, where possible, those infected with influenza should try to avoid close contact with others.