Influenza Virus: Causes, Symptoms, Types, Risk Factors, Examination, Diagnosis and Treatment

An infection with the influenza virus causes a disease which is known as the flu. Headaches, body aches, a sore throat, a fever, and potentially serious respiratory problems are some of the symptoms it produces. Wintertime is when flu outbreaks occur and it can affect a large number of individuals at once.

Symptoms Of Influenza Virus

The flu's most typical signs and symptoms include:

• The quick onset of a severe fever (38°C or higher)
• A dry cough, bodily aches (particularly in the legs, lower back, and head)
• A sensation of acute weakness and exhaustion that makes it difficult to get out of bed.

Additional signs include

• Pain behind-the-eye 
• Chills
• Appetite loss
• Painful throat
• Runny or stuffy nose.

If you have had contact with someone who is already sick, you are even more likely to have the flu.

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Causes Of Influenza Virus

The flu is caused by the influenza virus.

Tiny airborne droplets emitted when someone coughs or sneezes are the main way that the virus is spread. You run the risk of getting infected with the flu if you touch your mouth, nose, or eyes after coming into contact with something that has the virus.

Colds and the flu are frequently confused among people. You might have some of the same symptoms even though they are distinct. A lot of people get cold all year round. On the other hand, the flu frequently only affects persons incidentally.

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Types Of Influenza Virus

The family Orthomyxoviridae (a subfamily of RNA viruses) has a number of closely related viruses that can cause influenza. Types A, B, C, and D influenza viruses are distinguished. These primary varieties typically exhibit overlapping symptoms but are fully distinct antigenically, therefore infection with one type does not provide immunity against the others. 

The major influenza epidemics are brought on by influenza A viruses, while localized outbreaks are brought on by influenza B viruses. The C viruses only seriously afflict humans with a slight respiratory ailment. Because they have only been seen in pigs and cattle, influenza D viruses are not known to infect humans.

Influenza A viruses are separated into subtypes, and influenza B and its subtypes are further broken down into strains. Hemagglutinin (H) and neuraminidase (N), two surface antigens (foreign proteins) that distinguish influenza A subtypes, are the key distinguishing factors. 

The influenza A subtypes H1N1, H5N1, and H3N2 are among the examples. B/Yamagata and B/Victoria are the two main lineages into which influenza B viruses can be classified. Variations in the genetic sequence further separate influenza A subtypes from influenza B subtypes.

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Risk Factors Of Influenza Virus

The following variables may affect your risk of contracting the flu or its complications:

• Age. Seasonal influenza usually affects people more severely in children under two and those over 65.
• Living or working conditions. People are more likely to get the flu if they live or work in places with a lot of people, such as nursing homes or military barracks. Patients in hospitals are also more at risk.
• The immunological system that is compromised. HIV/AIDS, blood cancer, anti-rejection medications, prolonged steroid use, organ transplant, cancer treatments, and anti-rejection medications can all affect the immune system negatively. This could make issues and the chance of contracting the flu more likely.

The flu is often not a dangerous condition in young, healthy persons. It usually goes away after a week or two with no lasting effects. However, vulnerable kids and adults might deal with problems like:

• Pneumonia
• Bouts of asthma, bronchitis
• Heart problems
• The scenario of acute respiratory distress due to infected ears
• Pneumonia is one of the most harmful side effects. For people who are elderly or have a chronic illness, pneumonia can be lethal.

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How Can The Influenza Spread?

Through direct or indirect contact with an infected person, the influenza virus can spread. The following are typical flu transmission methods:

from a nearby person talking, sneezing, or coughing. Droplets may land on your hands or go through the air and enter your mouth or nose. After that, the flu spreads to your lungs.

by touching your face, nose, mouth, or eyes after coming into contact with a surface that has been exposed to the flu virus. This includes objects like desks, computers, phones, and doorknobs.

By contacting your face, nose, mouth, or eyes after contacting the hands or face of someone who is ill with the flu.

The influenza virus itself can lead to difficulties, or it can impair your immune function and make it easier for bacteria to spread to various places of your body (secondary infection). Included in the complications and subsequent infections are:

• Ear infections.
• A sinus infection.
• Significant lung infection (pneumonia). Acute respiratory distress syndrome (ARDS), in addition to other potentially fatal diseases, can result from pneumonia.
• (Miscarriage) Pregnancy loss.
• In the growing fetus of a pregnant woman, neural tube defects (NTDs).

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Diagnosis Of Influenza Virus

Your doctor will examine you physically, look for flu-related symptoms, and possibly suggest a test to look for influenza viruses.

In cases where the flu is widespread, you might not need to get tested. Your doctor might establish a diagnosis based on your symptoms.

In some cases, your doctor may advise that you get tested for influenza. Your doctor may do a number of tests to determine whether you have the flu. Polymerase chain reaction (PCR) testing is used more often to diagnose influenza nowadays. This examination could be done at a hospital or at the workplace of your healthcare provider. PCR testing, which is more accurate than other techniques, can be used to determine the flu strain.

Both the flu and COVID-19 can be diagnosed with a single test. It's possible for you to have COVID-19 and influenza simultaneously.

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Treatment Of Influenza Virus

Usually, all you need to get better from the flu is rest and lots of fluids. Your physician could suggest using an antiviral medication to treat the flu, though, if you have a severe infection or are more prone to develop complications. These drugs include, among others, baloxavir (Xofluza), zanamivir (Relenza), peramivir (Rapivab), and oseltamivir (Tamiflu). These medications may shorten the course of your sickness by one or two days while also assisting you in avoiding potentially fatal outcomes.

The medicine oseltamivir is taken by mouth. An apparatus resembling an asthma inhaler is used to administer zanamivir. Anyone taking it should not have certain chronic respiratory conditions, such as lung disease or asthma.

Antiviral drugs may cause nausea and vomiting as side effects.

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Prevention Of Influenza Virus

The best way to prevent the flu is to be vaccinated against it every year. Through immunizations, the immune system is taught to recognize infections and ward them off before you become unwell. Since the influenza virus tends to change (mutate) a little bit each year, you should get vaccinated.

Even if you get the flu from a strain other than the one in the vaccination, the vaccine reduces your risk of getting a serious disease. Your doctor can give you the flu shot, or you can opt to have a nasal spray immunization instead.

There are more methods you can reduce your chance of contracting the flu, such as:

• Wash your hands frequently with soap and water. If you are unable to wash your hands with soap and water, sanitize your hands using an alcohol-based product.
• Cover the mouth and nose while coughing or sneezing. Use your elbow or a tissue to cough or sneeze instead of using your bare hands.
• Avoid contact with others if you or a loved one has the flu or another contagious illness.
• Consider donning a mask if you need to be around others but can't avoid being ill.
• Avoid touching your face, eyes, nose, or mouth.
• No one else may use your forks, spoons, cups, or food.

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