The flu is a common ailment that affects over 20 million people every year in the country, but do we really know the basics of this infectious illness? Read on to know the essentials.

What is flu?
Also called influenza, the flu is a viral infection. It is highly contagious, and it can be a mild or severe condition. It is most infectious when its symptoms are yet to surface, that is, during the incubation period of the virus, at least 24 hours before the signs of the illness become noticeable.

When does seasonal flu affect people?
Flu can affect people all through the year, but the flu virus is most vigorous and rampant in winter and in early spring. There is less humidity during these seasons, which lets the flu virus anchor itself better in the air. It can survive more comfortably and for a longer time in the atmosphere when the air is heavy. This is also the reason why the flu virus circulates easily in air-conditioned environments and inside airplanes, where the humidity is comparatively lesser.

What causes flu?
Most cases of flu are a result of the influenza virus that transmits easily through respiratory secretions. The four different types of this virus are as follows:

• Influenza A virus that causes infection in humans, mammals, and birds spreads from animals to humans and can cause a widespread epidemic.
• Influenza B virus is known to infect only humans and seals.
• Strains of the Influenza A and B virus can both become critical and life-threatening.
• Influenza C virus infects humans and pigs. Although rarer when compared to the A and B strains, this type of the influenza virus can also cause grave symptoms.
• Influenza D virus infects pigs and cattle and is not known to cause harm to humans.

Which parts of the body does the flu affect?
The flu affects both the upper and lower respiratory tracts and the nose, throat, and lungs. It spreads through coughing, sneezing, and/or talking when droplets of saliva or respiratory secretions are inhaled by a person standing near an infected person, and the flu infection is similar to a common cold. While body aches, chest congestion, coughing, headache, fatigue, sore throat, and sneezing are some common symptoms of both flu and cold, a high fever is an exclusive trait of the flu. Also, the sudden appearance of the symptoms of flu and their acute and intense strength is quite different compared to that of the symptoms of common cold.

Who is at higher risk of contracting the flu?
Children below the age of 5 whose immune systems are not well developed, senior people over the age of 65 whose immune systems are weakened because of age, pregnant women, and anyone having impaired immunity or chronic health conditions are at relatively higher risk of being affected by the flu virus.

Why is the flu considered dangerous?
When the inflection becomes complicated, the flu virus can cause or worsen asthma, congestive heart failure, dehydration, diabetes, ear infections, encephalitis, kidney and respiratory failure, myocarditis, pneumonia, and sinus infections.