All about flu

Seasonal flu is an acute respiratory infection caused by the various viruses in the influenza virus family. There are three types of influenza virus: A, B and C. All three can infect human beings, and type A can also infect certain animals (birds, swine, horses, etc.). Type-A viruses have 16 H subtypes and 9 N subtypes.

Seasonal flu should not be confused with a cold or a chill.

It spreads across the globe from west to east, and is usually due to the Type-A flu virus H1N1, but may also be caused by the Type-A virus H3N2, or less commonly, by Type-B viruses.

Transmission

The flu virus can very easily be transmitted from person to person, by:

• airborne transmission: that is, transmission through the air as a result of coughing or sneezing, or droplets of saliva,
• direct contact with an infected person at less than a metre distance: a handshake, a hug, a kiss, etc.
• indirect contact with objects which an infected person has touched, and thus contaminated: e.g. door handles, banknotes, etc.

Treatment

It is possible to alleviate the symptoms of flu, such as fever and muscle aches, with a paracetamol-based medication.

Aspirin (acetylsalicylic acid) is not recommended for children and adolescents.

For as long as you have symptoms, you need to stay at home, drink plenty of fluids, and rest.

It is advisable for people with a high risk of developing complications to take prescription antiviral medicines.

How can I better protect myself from seasonal flu?

The flu virus can easily be transmitted through sneezing or coughing, particularly in enclosed spaces. Infected people, even if they do not yet have symptoms, can still pass the virus on to those around them.

Remember to follow simple hygiene measures to limit infection risks.

• Wash your hands for 30 seconds with soap and water, several times a day. Rub your palms together in a rotating motion. Do not forget your fingers, under your fingernails, and the backs of your hands.
• Cover your mouth and nose with a tissue when coughing or sneezing. If you don't have a tissue, cough or sneeze into the crook of your arm.
• Avoid bodily contact: hugs, kisses, handshakes.
• Avoiding crowds and gatherings during the flu season.
• Throw used tissues in the bin immediately, and then wash your hands.
• If you don't have a tissue: cough or sneeze into the crook of your arm.
• Stay at home while you have the flu.
• Air out your rooms regularly: 3 to 4 times a day for 10 minutes at a time.

Sentinel surveillance of flu

Flu is continuously being monitored, because it can cause serious complications in children, the elderly and people suffering from other conditions which leave them vulnerable to pneumonia.

Type-A viruses in particular, each year, infect a large number of people during the cold season, causing a considerable number of deaths the world over.

In Luxembourg, sentinel surveillance of flu is done collaboratively by the microbiology unit at the National Health Laboratory (Laboratoire national de santé - LNS), the Health Directorate (Direction de la santé) and a countrywide network of general practitioners and paediatricians.

Every week during the flu season (October to April), the general practitioners and paediatricians report the number of patients they have seen presenting with flu-like symptoms, the number of patients with acute respiratory infections, and the number of patients they have seen in total.

The general practitioners and paediatricians take nasal swabs from some of these patients, and send them to the LNS for virological analysis, which can detect the presence of Type-A or B influenza viruses.

The results of these weekly analyses can be viewed on the LNS website, in the 'Statistics' section.

More information is available at lns.lu/en/.