DETTOL Germ Protection Centre: Bird Flu Basics

Influenza (flu) is a highly infectious viral disease of the respiratory system (nose, airways and lungs). In the UK (and other temperate climates), outbreaks of flu tend to be 'seasonal' - the infection usually occurs during the winter months (from October to April). Seasonal prevalence is much less marked in tropical countries.

What causes influenza?

Influenza (flu) is caused by a virus. There are three main types of influenza virus:

Type A: These are responsible for most cases of human influenza. Some strains can cause epidemics. Some strains cause disease in animals, such as birds, pigs and horses.
Type B: These are less common and usually cause less severe illness, but can sometimes cause outbreaks - particularly amongst children.
Type C: These viruses usually only cause mild illness and are rare.

How do flu viruses spread from one person to another?

Human influenza viruses spread in tiny droplets, expelled from the mouth and nose of an infected person when they talk, cough or sneeze. You can get infected if you breathe in these droplets or if you touch someone or something that is contaminated with the virus (e.g. a used tissue or door handle), and then touch your nose or eyes.

How long is a person infectious?

People who have flu are usually infectious (i.e. they can spread the virus to others) from the day before to five days after they develop symptoms. Children can be infectious for longer.

Why does seasonal influenza usually occur in the winter?

Influenza viruses have more opportunity to spread from one person to another when people congregate indoors during the winter months. The more humid air indoors may help the influenza viruses to survive longer on surfaces where they can be picked up by people.

What are the symptoms of seasonal influenza?

Flu symptoms usually start suddenly and may include;

a fever (i.e. a temperature of 38 ºC or more)
headache
muscle aches
tiredness
a dry cough
sore throat
a runny or blocked nose and sneezing
stomach symptoms such as nausea, vomiting and diarrhoea (more common in children).

The incubation period (i.e. the time from picking up the virus to when symptoms start) is between one and four days. The symptoms peak after another two or three days and most people start to feel better within eight days. However, coughing and tiredness can continue for up to three weeks.

Is seasonal influenza a serious disease?

People who are otherwise fit and healthy, usually make a full recovery. However, complications, such as bronchitis and pneumonia, can affect people who are more vulnerable, such as the elderly, newborn babies, and those with certain medical conditions. This can cause serious illness, requiring hospitalisation and may be life threatening. Many people, mainly older people, die from flu every winter.

Pneumonia can develop as a direct result of infection with an influenza virus or from a 'secondary' infection caused by bacteria, such as Staphylococcus aureus.

Who is at risk?

Anyone can get flu, but the risk of developing complications and serious illness is higher for people aged 65 years and over, newborn babies, and people of any age with a chronic medical condition, particularly chronic respiratory and heart disease. Young children are more likely to develop influenza symptoms because they will not have had the opportunity to develop immunity to the virus.

Is there a vaccine to protect us from seasonal influenza?

Yes. The influenza vaccine (flu jab) provides protection against recently circulating strains of influenza A and B. However, since the viruses that cause flu mutate and change frequently, scientists have to make a new vaccine every year. This means that those at risk need to be immunised annually (usually in the autumn) in order to stay protected.

Should I be immunised?

You may need an annual influenza immunisation (flu jab) if you;

are aged 65 years or over
live in a nursing or residential home
have a chronic condition such as a heart problem, respiratory disease (e.g. severe asthma), kidney disease or diabetes
have a weak immune system due to disease (e.g. HIV), treatments such as steroid medication or cancer treatment, or a damaged or absent spleen
have a chronic neurological disease or have had a stroke
care for an older or disabled person whose welfare may be at risk if you are ill
are a health or social care professional directly involved in caring for patients.

The NHS also offers influenza immunisations to people who work in close contact with poultry (see Bird flu basics for more information.).

Most GPs organise special flu clinics every autumn, between September and early November. They usually contact registered patients who need to be immunised. However, if you do not receive an invitation to attend a flu clinic, and you think that you need to be immunised, contact your GP or practice nurse for advice.

Click here for the latest advice from the NHS about influenza immunisations.

What is an epidemic?

An epidemic is an outbreak of an infectious disease that affects an unusually high number of people within a country or region. Levels of seasonal influenza in the UK vary considerably from one year to the next depending on the type and severity of the circulating flu strains. The Health Protection Agency monitors levels of influenza. If an unusually high number of people consult their GP with flu symptoms in a week - they will declare a flu epidemic.

Click here to view the latest reports of influenza levels from the Health Protection Agency.

Why do we get epidemics of influenza?


Epidemics and pandemics (global outbreaks) can occur when a new influenza virus emerges.

Influenza viruses mutate (change) over time. Type A viruses in particular, can mutate rapidly so that new strains frequently arise. If a new strain is substantially different to strains that have previously circulated, the human population is unlikely to have any immunity to it. This enables the new strain to spread quickly and affect large numbers of people.

Type B influenza viruses are more stable - they do not mutate as readily as Type A viruses and are therefore less likely to cause epidemics. People who have had an influenza B infection, develop immunity that lasts for many years. Outbreaks of influenza B mainly affect young children who have not previously encountered Type B viruses and have not developed any immunity.

Click here for more information from the Health Protection Agency.

What are antiviral drugs?

Antiviral drugs are a type of medicine that doctors can prescribe to help fight the influenza virus. These medicines do not provide a cure, but they may reduce the severity and duration of the symptoms. These drugs can cause side-effects and are not suitable for everyone, so your doctor should only prescribe them if you are at serious risk of complications. Most people recover quickly from seasonal influenza without the need for antiviral drugs.

Click here for advice about flu treatments from NHS Direct.

Why can't we use antibiotics to treat influenza?

Antibiotics are medicines used to treat infections caused by bacteria. They do not work against viral infections, such as influenza. However, people with influenza sometimes develop complications caused by bacteria, such as pneumonia. In which case, they may need to take antibiotics to destroy the bacteria.

How can I stop influenza spreading?


During an influenza epidemic, staying away from crowded places may help to reduce your risk of infection.

Good hygiene habits are important. They help to stop influenza viruses spreading from one person to another.

Frequently wash your hands with soap and water.
Use a tissue to cover your mouth and nose when coughing or sneezing.
Put used tissues (and the germs) in the bin and remember to wash your hands afterwards.
Clean hard surfaces (e.g. kitchen worktops, door handles) frequently.

How does washing my hands protect me?


Washing your hands frequently can help to protect you from a wide range of infections.

Washing your hands frequently is the best way to protect yourself from a wide range of illnesses - not just influenza. Everytime you touch something, germs can transfer to your hands. Touching your eyes, nose or mouth with unwashed hands could transfer these germs from your hands into your body. Washing your hands frequently helps to remove the germs and stop them spreading to you and other people.

Click here for more information about how and when you should wash your hands.

How can I remove flu viruses from surfaces?

An infected person may spread germs to surfaces around them when they cough or sneeze, or touch them with unwashed hands or used tissues. Cleaning surfaces regularly can help to stop the influenza viruses spreading around your home, to you and other people.

Cleaning surfaces with detergent and water can remove sufficient germs from an item provided you scrub all the surfaces and rinse them thoroughly with clean water. However, where proper rinsing is not possible (e.g. large or fixed surfaces such as kitchen worktops, toilet flushes and door handles) it is important to use a disinfectant to kill the germs. The most important surfaces to clean and disinfect are those that people often touch with their hands, such as;

handles and switches
taps and toilet flush handles
kitchen worktops
telephone receivers
computer keyboards.

Cleaning and disinfecting surfaces using products that destroy influenza viruses will give extra reassurance.

Click here to find suitable disinfectants.

Click here if you have any questions about using Dettol products.

What should I do if I develop flu symptoms?

If you develop flu-like symptoms during the current swine flu pandemic (see our Swine Flu Pandemic Guide) it is important that you follow the latest government advice. Click here for the latest advice from NHS Direct.

For seasonal flu, the usual advice is to:

Stay at home and rest, keeping away from others as much as possible whilst you are infectious.
Drink plenty of fluids.
If necessary, take medicines such as paracetamol to relieve the symptoms. (Always read the label. Children under 16 years should not take aspirin.)
Use good hygiene at all times, and particularly while infectious.

If you are usually fit and healthy, you will not normally need to consult your GP. However, you should seek medical advice if your symptoms are severe, last more than a week, or if there is a risk of complications (e.g. because you have a chronic illness such as heart or lung disease, diabetes or asthma).

If I have influenza, where can I get advice?

Your health care provider (e.g. your doctor, practice nurse or health visitor) can provide advice about treating seasonal influenza. In England and Wales, you can also get advice from NHS Direct online, on digital satellite television by pressing the interactive button on your remote control, or by telephoning 0845 4647. The equivalent service in Scotland is NHS 24, which you can access online, or by telephoning 08454 24 24 24.

Where can I get more information?

You can get more information about seasonal influenza from the;