Influenza

Influenza is an acute viral infection that spreads easily among humans and attacks the respiratory system. A person becomes infected through the nose and mouth up to the lungs. It ranges from mild to severe and affects all age groups.

What Are the Types of Influenza Viruses?

Influenza viruses are divided into four main types, some of which infect humans and others infect animals:

Virus	What it infects	Notes
Influenza A and influenza B	Humans	The causes of seasonal influenza infections that spread in the winter season.
Influenza C	Humans	The cause of influenza infections throughout the year.
Influenza D	Livestock	Cannot be transmitted to humans.

There are subtypes of influenza A, and they differ according to the protein (H or N) that coats the virus, as there are 18 types of H protein and 11 types of N protein.

How Does Influenza Spread?

• Inhaling droplets of an infected person spreading in the air when sneezing or coughing.
• Touching surfaces contaminated with the virus and then touching the eyes, mouth and nose.

Incubation and Infection Periods

Incubation Period

The incubation period for influenza is usually 2 days but can vary from 1 to 4 days.

Period of Infection

It ranges from one day before symptoms appear to 5-7 days after. This period can last longer in children and people who suffer from immunodeficiency.

What Are the Symptoms?

• An increase in body temperature of more than 37.8 degrees Celsius, although some infected people may not have an increase in body temperature.
• Chills and sweating.
• Headache.
• Persistent dry cough.
• Fatigue and exhaustion.
• Runny nose.
• Sore throat.
• Muscle pain.

Risk Factors

• Age.
• Presence of chronic diseases.
• Weak immune system.
• Obesity.

Groups Most at Risk

• Health field workers.
• People with chronic diseases.
• Children.
• The elderly.
• Pregnant women.

What Are the Complications?

Pneumonia is the most common complication. It is a serious infection that affects the lungs and is more likely to occur in:

• Young children.
• People over the age of 65.
• Those with other diseases (such as diabetes) or conditions that affect the heart, lungs, or those who suffer from weak immunity.

Other complications include:

• Bronchitis.
• Sinus and ear infection.
• People with asthma may suffer from asthma attacks during the flu.
• Myocarditis.
• Respiratory infection with influenza virus can trigger a severe inflammatory response in the body and can lead to sepsis.
• Death.

When to See a Doctor

Most people with influenza only need to rest at home. But when the severity of the illness increases and it continues for more than two weeks, a doctor must be seen, as taking medications within the first 48 hours helps prevent more serious problems.

How Is Influenza Treated?

Most people with influenza recover within one to two weeks without treatment. However, serious complications can occur.

Usually treatment is rest and drinking plenty of fluids only. As for medications:

• Antiviral medications: in some cases the doctor may prescribe them. The medication does not eliminate the symptoms of influenza, but it can reduce the severity and duration of symptoms by about one day.
• Analgesics and antipyretics: fever, headache, and muscle pain can be relieved with them.
• Cough and cold medications: cough medications are usually not helpful; the cough usually goes away without treatment. So cough or cold medications are not recommended for children under 6 years of age, and warm liquids are enough.
• Antibiotics: they are not useful in treating viral diseases (such as influenza). They are only used in the case of bacterial complications of influenza (such as bacterial pneumonia, ear infection, or sinusitis).

How Can Influenza Be Prevented?

Get the seasonal influenza vaccine annually, as it is the most effective way to reduce the chance of infection.

• Wash hands well and regularly with soap and water.
• Avoid touching the eyes or mouth immediately after touching surfaces.
• Avoid direct contact with the infected person and sharing tools.
• Use a tissue when sneezing and coughing and dispose of it immediately.
• Clean surfaces regularly (such as tables and chairs).
• Avoid crowded places.