What is Influenza (Flu)?

Last Update on September 14, 2022

Medically reviewed by Angelena Maria Labella, MD

Influenza (Flu) is a common respiratory illness put on by influenza viruses that can sometimes spread to the lungs as well as the nose and throat. It can cause mild to severe disease, and occasionally even death. Influenza vaccines against the flu every year are the greatest approach to preventing the virus.

A virus disease known as influenza targets the respiratory system, including the nose, throat, and lungs. Although influenza is also known as flu. It varies from stomach “flu” viruses that result in vomiting and diarrhea. From 2 to 4 days is the incubation period for flu.

The flu often goes away on its own for most people. But occasionally, flu and its side effects might be fatal. Those who are more likely to experience flu complications include:

  • Children under the age of five, in particular, those under six months
  • Adults who are above 65
  • Residents of long-term treatment centers such as nursing homes
  • Ladies who are pregnant and those who have given birth up to two weeks ago
  • Those whose immune systems are weak
  • American Indians
  • Chronically unwell individuals, including those with diabetes, heart disease, renal disease, asthma, and other diseases
  • Those with a body mass index (BMI) of 40 or above and severe obesity
  • The annual flu vaccine remains your best line of defense against the flu, despite its imperfect effectiveness.
  • Symptoms of Influenza (Flu):
  • The flu may initially appear to be a typical cold with a runny nose, sneezing, and sore throat. But colds typically come on gradually, but the flu typically strikes rapidly. And while a cold might be annoying, the flu typically makes you feel considerably worse.

1. Signs and symptoms of Influenza:

Common signs and symptoms are:

  • Fever
  • Aching muscles
  • Chills and sweats
  • Headache
  • Dry, persistent cough
  • Shortness of breath
  • Tiredness and weakness
  • Runny or stuffy nose
  • Sore throat
  • Eye pain
  • Vomiting and diarrhea

Get medical treatment right once if you show severe flu symptoms. Adults may experience the following emergency symptoms and signs:

  • respiratory issues or lack of breath
  • Chest pain
  • Ongoing dizziness
  • Seizures
  • The worsening of current medical issues
  • muscular ache or extreme weakness

Emergency signs and symptoms in children:

  • Difficulty breathing
  • Blue lips
  • Chest pain
  • Dehydration
  • Severe muscle pain
  • Seizures

2. Causes of Influenza (Flu):

The majority of specialists believe that flu viruses are mostly spread by the tiny droplets released when sick people cough, sneeze or talk. There are 4 types of influenza viruses A, B, C, and D that cause influenza in humans. People close may catch these droplets in their mouths or noses. Less frequently, someone can contract the flu by contacting anything or a surface that has the virus and then contacting their own mouth, nose, or possibly eyes.

Droplets of influenza viruses are released into the air when an infection coughs, sneezes, or speaks. You can either directly breathe the droplet or take up the bacteria from a surface, such as a phone or a computer keyboard, and then transmit it to your eyes, nose, or mouth.

People who have the virus are most likely active from a day or so before symptoms emerge to a week or so after they do. Children and those with weak immune systems may cause disease for a little while longer.

As a result of continuing evolution, influenza viruses routinely develop new types. Your body has already built antibodies to combat that particular strain of the virus if you’ve previously experienced influenza. These antibodies may prevent infection or lower the severity of infection if future flu viruses are comparable to those you’ve already met, either by contracting the illness or receiving the vaccination. But over time, antibody levels can drop.

Additionally, you could not be protected from new influenza viruses that can be very different viruses from what you had previously by antibodies against flu viruses you have already experienced.