Demystifying Influenza :Types, Symptoms, causes and more

Influenza, often referred to as the flu, is a familiar yet mysterious ailment that affects millions every year. Despite its prevalence, there’s a lot about influenza that remains misunderstood. In this comprehensive guide, we will unravel the complexities surrounding this viral infection. From its types and symptoms to causes, treatments, prevention strategies, diagnosis methods, and risk factors, we’ll leave no stone unturned.

What is Influenza?

Influenza, or the flu, is a contagious respiratory illness caused by influenza viruses. It can lead to mild to severe symptoms and, in some cases, even death. Understanding its types is the first step in demystifying this illness.

Types of Influenza

Influenzas, commonly known as the flu, is cause by several different types and subtypes of influenza viruses. The three main types of influenzas viruses that infect humans are influenza A, influenza B, and influenza C. Each type has different characteristics and subtypes, which can further complicate the classification of flu viruses. Here’s an overview of these three main types:

Influenza A (H1N1, H3N2, etc.):

Influenza A viruses are the most diverse and can infect both humans and animals, such as birds and pigs. They are categorize base on the surface proteins hemagglutinin (H) and neuraminidase (N). Common subtypes of influenza A that have caused human pandemics in the past include H1N1 and H3N2. Seasonal flu vaccines often include protection against specific influenza A subtypes.

Influenza B:(H and N)

This  viruses primarily infect humans . Influenza B viruses are not categorized by H and N subtypes  further divided into two main lineages: Victoria and Yamagata. Seasonal flu vaccines typically contain protection against both influenza B lineages to provide broader coverage.

Influenza C:

Influenza C viruses are less common and generally cause milder respiratory illness than influenza A and B. They typically do not cause seasonal flu outbreaks to the same extent. Influenza C viruses do not have distinct H and N subtypes and are less studied in comparison to the other two types.

It’s important to note that influenza A viruses, particularly certain subtypes, have the potential to undergo significant genetic changes through processes like antigenic shift and antigenic drift.

Influenza A symptoms

Influenza A, like other types of influenzas, can cause a range of symptoms that typically affect the respiratory system. Symptoms can vary in severity, and some people may experience more intense symptoms than others. Common symptoms of Influenzas A include:

  • High fever is a hallmark symptom of influenza A and is often one of the first signs of the infection.
  • Influenza A can lead to a dry or productive cough that may be persistent and worsen over time.
  • Many people with influenza A experience a sore throat, which can be painful and make swallowing uncomfortable.
  • Nasal congestion, sneezing, and a runny nose are common symptoms of the flu.
  • Muscle aches and joint pain, often referred to as myalgia and arthralgia, can be quite severe with Influenza A.
  • Headaches are a common symptom and can range from mild to severe.
  • Profound tiredness and fatigue are common with the flu, and they can last for several weeks in some cases.
  • Shivering and feeling cold are frequent symptoms, especially during the feverish phase.
  •  Influenza A can cause a general feeling of weakness and malaise.
  • In some cases, influenza’s can cause gastrointestinal symptoms like nausea, vomiting, and diarrhea, although these are less common.

How Does Influenza Spread?

Influenzas spreads primarily through respiratory droplets when an infected person coughs, sneezes, talks, or even breathes. Here’s a more detailed explanation of how influenzas spreads:

Respiratory Droplets:

When someone with influenzas coughs, sneezes, or talks, they release tiny liquid droplets containing the influenza virus into the air. These droplets can carry the virus and infect others who come into contact with them.

Close Contact:

Influenza’s is highly contagious, and it can spread easily when people are in close contact with an infected person. This includes being within about six feet of someone who is sick with the flu.

Touching Contaminated Surfaces:

In addition to respiratory droplets, the virus can also be present on surfaces and objects that an infected person has touched, such as doorknobs, countertops, or shared items like phones and utensils. If a person touches a contaminated surface and then touches their mouth, nose, or eyes, they can introduce the virus into their body.


Preventing the Spread of Influenza A

Preventing the spread of Influenza A (the flu) is crucial to reduce the risk of illness and protect public health. Here are specific steps to prevent the spread of Influenza A:


The most effective way to prevent Influenzas is by getting an annual flu vaccine. These vaccines are designed to protect against the specific strains of Influenza’s that are expected to be prevalent during the flu season. Vaccination not only reduces your risk of getting sick but also helps prevent the spread of the virus within the community.

Hand Hygiene:

Practicing good hand hygiene is essential. Wash your hands frequently with soap and warm water for at least 20 seconds, especially after coughing, sneezing, touching your skin, or being in public places. If soap and water are unavailable, use hand sanitizer containing at least 60% alcohol.

Avoid Close Contact:

If you have Influenzas symptoms or have been diagnosed with the flu, stay home to avoid spreading the virus to others. Practice social distancing by staying at least six feet away from people who are sick.

Face Masks:

Wearing a mask, especially in indoor public spaces and crowded areas, can help reduce the spread of respiratory droplets that may contain the virus. Masks are particularly important during flu outbreaks and pandemics.

Avoid Touching Your Face:

Refrain from touching your eyes, nose, and mouth, as this can introduce the virus into your body if your hands are contaminated.


Ensure good ventilation in indoor spaces by opening windows and using fans to increase air circulation. Proper ventilation can help reduce the concentration of airborne virus particles.

How to treat ?

Treatment for influenza’s (the flu) primarily focuses on relieving symptoms, managing complications, and reducing the severity and duration of the illness. Here are some key aspects of treatment for influenza’s:

Antiviral Medications: Antiviral drugs can be prescribed by a healthcare provider to treat influenza, especially if started early in the course of the illness. There are two main classes of antiviral medications used for influenza’s:

  • Neuraminidase Inhibitors: Oseltamivir (Tamiflu), zanamivir (Relenza), and peramivir (Rapivab) are examples of neuraminidase inhibitors. They work by inhibiting the activity of the neuraminidase enzyme on the influenza virus, which helps prevent the virus from spreading within the body. These medications are most effective when taken within the first 48 hours of symptom onset.

  • Baloxavir Marboxil: Baloxavir marboxil (Xofluza) is a newer antiviral medication that works by inhibiting a different part of the influenzas virus life cycle. It can be taken as a single dose and is approved for use in some cases of uncomplicated influenzas.

Rest and Hydration:

Adequate rest and hydration are essential for recovery from the flu. Resting allows your body to focus its energy on fighting the virus, while staying hydrated helps prevent dehydration, which can worsen flu symptoms.


If you have the flu, it’s important to stay home from work, school, and other public places to avoid spreading the virus to others. Follow your healthcare provider’s recommendations on when it’s safe to return to normal activities.


Diagnosing Influenza A typically involves a combination of clinical evaluation and laboratory testing. Healthcare providers use these methods to confirm the presence of the influenza virus and distinguish it from other respiratory infections. Here’s how Influenza A is diagnosed:

Laboratory Testing:

  • Rapid Influenza Diagnostic Tests (RIDTs): These are commonly used in clinical settings to quickly diagnose influenza A and B. A swab is taken from the back of the throat or nasal passages, and the sample is tested for the presence of influenza’s virus antigens. RIDTs provide rapid results within about 15-30 minutes. However, their accuracy can vary, and false negatives are possible, especially late in the illness.

  • Molecular Tests (PCR): Polymerase chain reaction (PCR) tests are more sensitive and specific for detecting flu viruses. These tests are typically conducted in a laboratory and can distinguish between different influenza’s types  and subtypes. PCR tests are considered the gold standard for flu diagnosis.

  • Viral Culture: In some cases, viral culture may be used to confirm the presence of influenzas. This method involves growing the virus in a laboratory setting, which can take several days to yield results. It is less commonly used due to its longer turnaround time.

Influenza A vs Influenza B

CharacteristicInfluenza AInfluenza B
Types and SubtypesMultiple subtypes (e.g., H1N1, H3N2)Two main lineages: Victoria and Yamagata
HostsCan infect humans and animalsPrimarily infects humans
SeverityGenerally associated with more severe illnessTends to cause milder symptoms
SeasonalityResponsible for seasonal flu outbreaksAlso causes seasonal flu but may be less common
Antigenic VariationProne to significant antigenic changes through antigenic shift and driftLess antigenically diverse and stable
Vaccination CoverageIncluded in annual flu vaccines, targeting specific subtypesIncluded in annual flu vaccines, covering both lineages
PrevalenceTypically more common and widespreadMay be less prevalent in some seasons
Potential Pandemic StrainsMore likely to contribute to pandemicsLess likely to cause pandemics
Examples of PandemicsSpanish flu (H1N1, 1918), H1N1 pandemic (2009)None known to have caused pandemics
Antiviral ResistanceSome subtypes may develop resistance to antiviral drugsGenerally less likely to develop antiviral resistance

How is Influenza Different from the Common Cold?

CharacteristicInfluenza (Flu)Common Cold
Causative VirusesInfluenzas viruses (mainly types A and B)Various viruses, most commonly rhinoviruses
Onset of SymptomsSudden and abruptGradual and slow
Severity of SymptomsOften more severeGenerally milder
Common SymptomsHigh fever, body aches, cough, sore throat, headache, fatigueRunny or stuffy nose, sneezing, mild sore throat, occasional cough, mild fatigue
FeverCommon, often highLess common, if present, usually mild
Duration of Illness1-2 weeks, with lingering fatigueSeveral days to a week


 Influenza is a formidable adversary that demands respect and understanding. Armed with knowledge about its types, symptoms, causes, treatments, prevention strategies, diagnosis methods, and risk factors, you can better protect yourself and your loved ones from its grip.


1.What causes influenza?

Influenzas, also known as the flu, is a respiratory illness caused by influenzas viruses. There are three types of influenzas viruses: A, B, and C. Influenza A and B viruses are the most common types that infect people and cause seasonal flu epidemics. Influenza C virus infections are typically mild and do not cause seasonal epidemics.

2.How long does influenza a last?

Influenzas, also known as the flu, typically lasts for 3-7 days. However, some people may experience symptoms for longer, especially young children, the elderly, and people with chronic health conditions. The cough and tired feeling may last for weeks, even after other symptoms have resolved.

3.Is influenza A very serious?

Yes, influenza A can be a very serious illness. It is the most common type of influenzas virus and can cause severe illness and death, especially in young children, the elderly, and people with chronic health conditions.

4.How infectious is influenza A?

Influenza A is a very infectious virus. It can spread from person to person through respiratory droplets produced when an infected person coughs or sneezes. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Less commonly, a person can get the flu by touching a surface or object that has the flu virus on it and then touching their own mouth, nose, or eyes.

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