Influenza, also called the flu, is a common infection of the nose, throat, and lungs. It is caused by a virus, more commonly during winter. The disease can be transmitted from person to person and sometimes have serious outcomes, especially for people above 65 years, newborn babies, and people with chronic illnesses. Understanding the causes and symptoms of influenza and detecting it in time can help prevent the virus from spreading.

What causes influenza?
Influenza is caused by the influenza virus. It can spread easily from person to person. The disease is transmitted when infected people cough, sneeze, or talk, and the tiny droplets are inhaled by those nearby. One may also get infected by touching surfaces contaminated by the flu virus. The risk is higher in crowded places, such as schools and offices.

What are the types of influenza?
The three common types of influenza viruses that infect people are:

Influenza A
The influenza A virus is known to cause a flu outbreak that can spread worldwide. It affects not only humans but also birds, pigs, and other animals. This type of flu takes one to four days to incubate in humans. The infected person can spread the disease even before symptoms appear and they realize they are ill. When a new influenza A virus emerges, it can spread quickly as people have little or no immunity. The subtypes of influenza A are swine flu and bird flu.

Influenza B
This flu virus can cause seasonal outbreaks but is typically less severe than type A. Influenza B can be transmitted only from human to human.

Influenza C
In most cases, the influenza C virus does not cause outbreaks and is limited to a mild illness that one can easily manage. However, it can affect humans and even some animals.

What are the signs to look out for?
Flu symptoms usually come suddenly and may initially seem like a common cold. They may last from a few days to two weeks. People with this disorder may experience some or all of the following:

Fever
The flu virus always increases body temperature. So, one should not ignore a high fever of 38 degrees Celsius or more, as it could be a sign of influenza. Fever usually lasts for three to four days.

Body aches and chills
People with the flu may have head, back, and leg aches. Those with severe aches may find it challenging to perform even basic tasks. Further, the flu may cause chills even before a fever develops.

Sore throat
It usually occurs in the earliest stages of the flu. One’s throat may feel scratchy and irritated and worsen as the infection progresses.

Cough
A persistent dry cough can last for about two weeks. The influenza virus can also cause wheezing and chest tightness. With time, the cough can become severe and bring up phlegm or mucus. People with respiratory problems like asthma may need immediate attention to prevent further complications. Foul-smelling, colored phlegm is also a warning sign to seek professional help. Sometimes, the influenza virus can result in complications like bronchitis and pneumonia.

Runny or stuffy nose
A stuffy or runny nose is another sign. The flu virus can cause inflammation in the upper respiratory tract, resulting in a clear, watery nasal discharge. Next, the infected person may develop a stuffy nose and congestion. However, these symptoms go away in four to seven days.

Diarrhea and vomiting
The flu virus can cause gastrointestinal problems like diarrhea or vomiting, although not everyone experiences them. This symptom is more common in younger children. Children with such flu symptoms can also get dehydrated easily, resulting in complications.

Headaches
Headaches are common in those affected by the flu. It usually occurs along with other symptoms and can come on suddenly. Sometimes, the pain can be severe. The flu virus increases the pressure inside the head, causing feelings of heaviness and pain. Patients may also experience aches around and behind the eyes. This type of headache will not last more than a few days.

Fatigue
Influenza can make a person feel extremely tired. It happens because the immune system uses a lot of energy to combat the virus. Regaining energy may take weeks after all other symptoms have eased.

The flu can make a person miserable. If one thinks they have the flu, they must see a healthcare provider immediately. Individuals must wash their hands regularly and practice good hygiene to prevent the ailment. The best course of action is to get vaccinated.