What is the difference between Influenza and the Common Cold?
People often say "I’ve got the flu", when they actually have a common cold. Although a common cold can make you feel pretty bad, and has many symptoms that are similar to influenza, it is not the same thing. Unlike common cold, influenza causes severe illness and life-threatening complications in many people. An influenza infection is characterized by a very swift onset. People go from completely well to very sick in only a few hours. While you may cough and sneeze with the influenza, you're also likely to have a high fever, chills and body aches — signs and symptoms you won't typically have with a cold. Furthermore, real influenza usually doesn't affect your intestines. Colds generally do not result in serious health problems. Of the several viruses that can cause common cold, the role of rhinoviruses is the most prominent by causing 30-50% of the annual cases. Corona viruses cause 10-15% and influenza viruses cause 5-15% of the annual proportion of cases of ‘common’ cold.
What causes Influenza?
Two types of influenza viruses – type A and type B – are known to cause significant illness in humans. Both type A and type B have different strains that cause illnesses of varying severity. But the influenza A family has more virulent strains than the B family. From 1990 to 2000 there have been 9 significant outbreaks of influenza A in England and Wales and 4 outbreaks of influenza B.
What happens when you get influenza?
When an influenza-virus attacks the cells of the respiratory tract and enters it, the lining of the respiratory tract is damaged. The tissues become swollen and inflamed. It uses the cell’s reproductive system to reproduce itself. Within a very short period, it produces hundreds of new viruses. It takes about an hour for the virus to kill the infected cells. New viruses are released from the cells and these start attacking other cells. Fortunately, the damage is rarely permanent. The tissues usually heal within a few weeks. Influenza is often called a respiratory disease, but it affects the whole body.
How can I catch Influenza?
You get influenza from droplets of influenza virus in the air, caused by someone else with influenza coughing or sneezing or by direct contact. Inhalation of as few as three infective particles can transmit the infection, so you can catch influenza just by standing next to someone with influenza on the bus. The virus makes its way down to your respiratory tract and starts attacking the protective cells of the respiratory tract. As with common bacterial infections, young children are the most likely both to be infected and to spread influenza. When the influenza A virus is introduced into a family, 56% of households had at least 1 secondary case.
How long does it take between infection and getting ill?
The victim usually becomes acutely ill. The incubation period of influenza ranges from less than 1 to 7 days, but it usually lasts 2 to 3 days. This means that it can take up to seven days from catching it, to noticing the first symptoms.
What are the symptoms of Influenza?
Influenza in adults and adolescents typically presents with an abrupt onset of symptoms. These symptoms are referred to as "flu-like symptoms."
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Fever (usually high) and chills
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Headache
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Tiredness (can be extreme)
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Sore throat and coughing
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Runny or stuffy nose
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Body (muscle) aches
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Anorexia
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Diarrhea and vomiting also can occur but are more common in children
A lot of different illnesses, including the common cold, can have similar symptoms.
The fever (38-40 oC) peaks within 24 h of onset and lasts 1-5 days. Other physical signs include the appearance of being unwell, hot and moist skin, flushed face, blood-injected burning eyes and a clear nasal discharge. People with influenza usually feel very bad and prefer to stay in bed. Febrile convulsions are the initial sign in a number of children.
Is influenza considered serious?
For healthy children and adults, influenza is typically a moderately severe illness. Most people are back on their feet within a week.
For people who are not healthy or well to begin with, influenza can be very severe and even fatal. The symptoms described above have a greater impact on these persons. In addition, complications can occur. Most of these complications are bacterial infections because the body can be so weakened by influenza that its defenses against bacteria are low. Bacterial pneumonia is the most common serious complication of influenza. In addition the sinuses and inner ears may become inflamed and painful.
How long does a bout of Influenza last?
If you are healthy and suffer from an uncomplicated influenza attack, influenza illness starts to resolve after a limited number of days for the majority of persons, although cough and malaise can persist for more than 2 weeks. However, if you suffer from complications, such as pneumonia this may considerably affect the seriousness of the disease and its duration.
Can I have a recurrence of Influenza?
A person can have influenza more than once because the virus that causes influenza may belong to two different influenza virus families type A or type B. Furthermore, within these two families there are many viral strains, like so many brothers and sisters. The circulating viruses do not always stay the same they change continuously. If you have influenza, your immune system responds by developing antibodies, but these antibodies do not recognize an unfamiliar strain. Therefore, if the following year a new family member or a member of another family appears, we can get sick again.
The epidemiological success of influenza viruses is due to this variation. This is the reason that the influenza vaccine has to be adapted every year to these changes (also called mutations) in the virus.
Can I prevent Influenza?
The single best way to prevent influenza is to get vaccinated each fall. The principle of each vaccine is that a tiny bit of inactive influenza virus or only some components of the virus are injected into your body. The virus is inactivated to make sure it doesn’t infect your body cells and it cannot make you ill. This allows your body to make antibodies so that you become immune against the influenza viruses circulating this year. Contagion of influenza varies inversely with the level of immunity in the population, which is determined largely by the presence or absence of these antibodies.
What can I do about influenza, once I’ve got it?
Take plenty of rest and drink a lot of liquids, and avoid using alcohol and tobacco is usually the best remedy. Also, you can take medications to relieve the symptoms of influenza (but never give aspirin to children or teenagers who have influenza-like symptoms, particularly fever). The symptomatic treatment of colds has been aimed at relieving the most disturbing symptoms of the illness, and hundreds of different over-the-counter preparations are available. Your GP may prescribe an antiviral drug which can shorten the duration of your influenza symptoms by 1-2 days. This drug will only be effective if the treatment is started within 48 hours after the onset of influenza like symptoms. Antibiotics are not effective against viruses but they are widely used in the treatment of upper respiratory tract infections.
These steps may help prevent the spread of respiratory illnesses like influenza:
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When you are sick, keep your distance from others to protect them from getting sick too.
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Cover your nose and mouth with a tissue when you cough or sneeze—throw the tissue away after you use it.
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Wash your hands often with soap and water, especially after you cough or sneeze. If you are not near water, use an alcohol-based hand cleaner.
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Stay home from work, school, and errands when you are sick. You will help prevent others from catching influenza.
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Try not to touch your eyes, nose, or mouth. Germs often spread this way.
When should I go to the doctor?
Consult your physician whenever you are worried about your symptoms. You should in any case consult your physician in the following cases:
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when you belong to the risk groups and you think you have influenza
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when you have a cold for more than seven days
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when you have a fever of more than 40 degrees Celsius
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when your ears hurt
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when you have a headache that worsens when you bend over
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when you have a bad sore throat or your throat looks infected
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when your sputum is greenish or bloody
Emergency Warning Signs
There are some “emergency warning signs” that require urgent medical attention.
In children, emergency warning signs that need urgent medical attention include:
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Fast breathing or trouble breathing
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Bluish skin colour
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Not drinking enough fluids
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Not waking up or not interacting
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Being so irritable that the child does not want to be held
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Flu-like symptoms improve but then return with fever and worse cough
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Fever with a rash
In adults, emergency warning signs that need urgent medical attention include:
How frequently do influenza outbreaks occur?
Influenza outbreaks occur every year usually during winter or early spring, sometimes there can even be outbreaks of two different kinds of influenza. So every year you run the risk of catching influenza. Sometimes these outbreaks are of local epidemic or even worldwide proportions.
What is avian influenza (bird flu)?
Bird flu is an infection caused by avian (bird) influenza (flu) viruses. These influenza viruses occur naturally among birds. Wild birds worldwide carry the viruses in their intestines, but usually do not get sick from them. However, bird flu is very contagious among birds and can make some domesticated birds, including chickens, ducks, and turkeys, very sick and kill them. Bird flu viruses do not usually infect humans, but several cases of human infection with bird flu viruses have occurred since 1997.
The World Health Organization does not at present recommend any restrictions on travel to any country currently experiencing outbreaks of avian influenza, but contact with live animal markets and poultry farms in areas experiencing outbreaks of avian influenza should be avoided. Large amount of virus are known to be excreted in droppings from infected birds.
What is an epidemic?
We speak of an epidemic when the occurrence of cases of influenza in a community or region clearly exceeds the normal year-round frequency of influenza. Epidemics are self-limiting, because many people have been vaccinated against the influenza virus and others have already some protection against the virus that causes the influenza epidemic.
What is a pandemic?
Every 20 years or so, an influenza virus strain appears that is dramatically different from the other members of its family. This strain may be very virulent, and make people sicker than usual. When this major change occurs a worldwide epidemic, called a pandemic, almost inevitably follows because influenza spreads very quickly, especially with modern transportation methods such as airplanes. Few people have antibodies that are effective against the new virus. This virus has not yet been included in the vaccine. Until now, pandemics have always been caused by a type A-virus.
One such virus caused the 1918 Spanish Flu that swept the world and left in its wake more than 40 million dead (more than the First World War). There have been three major pandemics over the last century alone, in 1918, 1957 and 1968.
Another virus that swept the world this past season was the avian influenza virus. Avian influenza viruses are influenza A strains that infects birds. It is mainly transmitted to humans by direct contact with live, sick or dead poultry. Human to human transmission has not been identified to date. Among the human cases in Asian countries, such as in Thailand and Vietnam, the avian virus caused severe illness and high mortality.
Is there a relationship between influenza and SARS?
The Severe Acute Respiratory Syndrome (SARS) is caused by a corona virus and this virus cannot cause influenza. Influenza is much more contagious than SARS. Influenza vaccines do not protect against SARS. Currently, there is no known SARS transmission anywhere in the world. The most recent human cases of SARS-CoV infection were reported in China in April 2004 in an outbreak resulting from laboratory-acquired infections.
