Influenza: Causes, Symptoms, and Treatment

Influenza is a common respiratory condition that developed into epidemics and pandemics. It can cause marked morbidity and mortality and can transmit very quickly. Millions of people worldwide contract the flu each year, and many require hospitalization or medical care.

Influenza, commonly known as the flu, is a contagious respiratory illness affecting the nose, throat, and lungs. It is a viral infection caused by influenza viruses which can be divided into four types: 

- Influenza type A is the most common and can cause the most severe illness. 

- Influenza type B is less common and usually causes milder illness. 

- Influenza type C typically causes either no symptoms or mild symptoms and does not cause epidemics.

- Influenza type D viruses do not infect or cause illness in humans.

Though only three types of Influenza are responsible for infecting humans, Influenza A is majorly accountable for initiating pandemics because of its high susceptibility to antigenic variation. Unlike Influenza type C, Influenza A and B cause seasonal epidemics, generally in winter, and have more severe symptoms.

How does it spread?

Seasonal Influenza spreads easily and rapidly in crowded areas, including schools and nursing homes. When an infected person coughs or sneezes, their infectious droplets get dispersed into the air, spreading up to one meter, infecting all those nearby who breathe these droplets inside. The virus is also spread by hands contaminated with influenza viruses.

Certain climatic conditions are most susceptible to catching an Influenza infection. In temperate climates, seasonal epidemics are reported mainly during winter, while in tropical regions, they may occur throughout the year, causing outbreaks more irregularly.

Transmission of the Influenza virus can be prevented if the infected people take certain precautions by maintaining social distancing, covering their mouth and nose with a tissue while coughing, and washing their hands regularly.

What are the indicators of Influenza infection?

Influenza can begin suddenly and is usually accompanied by fever, chills, aches, pains, headaches, fatigue, cough, and generalized weakness lasting up to 14 days.

Children may experience atypical gastrointestinal symptoms like vomiting and diarrhea.

Influenza infection can further lead to certain clinical complications. Individuals with influenza infection may experience secondary bacterial pneumonia, post-influenza encephalitis, changes in the cardiac electrocardiogram, secondary bacterial infections, such as Staphylococcus aureus-induced myositis, and multiorgan failure. However, extrapulmonary complications are rare.

Who are at risk?

All age groups can be affected, but some are more at risk than others. People at greater risk of severe disease or complications of Influenza are:

• pregnant women, 

• children under 59 months, 

• the elderly, 

• people with chronic medical conditions (like chronic cardiac, pulmonary, renal, metabolic, neurodevelopmental, liver, or hematologic diseases), and 

• Individuals with immunosuppressive conditions (like HIV/AIDS, receiving chemotherapy or steroids, or malignancy).

• Healthcare workers are also at high risk of acquiring influenza virus infection due to increased exposure to the patients, and the risk further spreads mainly to vulnerable individuals.

How is Influenza diagnosed?

Most patients in the outpatient setting receive a clinical diagnosis. Laboratory confirmation is generally optional. However, it may be helpful in hospitalized patients with suspected Influenza and patients for whom a confirmed diagnosis will change treatment decisions.

Rapid molecular assays are preferred as diagnostic tests for Influenza as they can be conducted at the point of care, are highly accurate, and render fast results.

How to prevent Influenza?

The influenza vaccine has a vital role in the prevention of the disease. Flu vaccines are widely available and can help reduce the risk of contracting the virus. Vaccines are recommended for everyone over six months, and certain high-risk individuals should get the vaccine every year. It is crucial to get the vaccine early in the season, as it takes up to two weeks to become effective. It is recommended not to avoid the influenza vaccine in egg-allergic patients routinely.

In addition to the vaccine, it is important to practice good hygiene to help prevent the spread of Influenza. General measures to prevent the spread of the flu are:

• It is essential to keep the home and workplace clean. 

• Regular cleaning of frequently touched surfaces such as doorknobs, countertops, and desks can help reduce the spread of the virus. 

• It is also important to keep the workplace well-ventilated to reduce the spread of the virus.

• Avoid touching the eyes, nose, and mouth.

• Stay home if you have flu-like symptoms. By staying home, you help prevent the spread of the virus.

How to manage patients with Influenza?

There are four approved anti-influenza drugs, one of which can be used if the patient presents within 48 hours of symptom onset. These drugs lower the duration of illness by nearly 24 hours in otherwise healthy patients and may also decrease the risk of serious complications. Over-the-counter medications can also help to reduce fever, body aches, and other symptoms.

The patient receives maximum benefits when antiviral therapy is initiated within 24 hours of symptom onset. However, Patients with severe illness or at high risk of complications from Influenza should get antiviral treatment irrespective of symptom duration.

Lifestyle measures for Flu management

• Drink plenty of fluids as dehydration can worsen flu symptoms. 

• Eat foods rich in Vitamin C, zinc, and probiotics as they boost immunity, fight off the virus and reduce the severity and duration of the flu.

• Rest is essential for recovery from the flu. Make sure to get plenty of sleep and rest as much as possible.

Finally, it is crucial to be aware of the signs and symptoms of Influenza. Patients who experience the symptoms of Influenza must quickly receive medical help, and all those who are eligible must get vaccinated annually to protect themselves from any complications. By following simple steps, you can help reduce the spread of Influenza and minimize its impact. With the proper management and prevention strategies, you can help protect yourself, your family, and your community from the virus.