Flu A - Symptoms, Causes, Diagnosis, Treatment and Prevention

What Is Flu A?

The influenza viruses that infect humans are divided into three groups: A, B, and C. Type-A influenza can be deadly, resulting in widespread outbreaks and disease. Common symptoms of type A infection can be mistaken for those of other conditions. While milder cases of influenza can resolve on their own without causing significant symptoms, severe cases of type-A influenza can be fatal.

Influenza viruses are classified into four types: A, B, C, and D. Human influenza A and B viruses cause seasonal epidemics of disease (known as flu season) in the United States almost every winter. The only influenza viruses known to cause pandemics, or global outbreaks of flu disease, are influenza A viruses. A pandemic can arise when a new and distinct influenza A virus appears that can both infect people and spread rapidly among them. Infections with the influenza C virus usually result in mild illness and are unlikely to cause human epidemics. The influenza D viruses primarily affect cattle and have not been found to infect or afflict humans.

The surface proteins of influenza A viruses are used to classify them into subtypes: hemagglutinin (H) and neuraminidase (N). There are 18 different subtypes of hemagglutinin and 11 different subtypes of neuraminidase. The process by which influenza viruses swap gene segments is known as reassortment. When two influenza viruses infect the same host simultaneously, they can swap genetic information. Influenza subtypes A(H1N1) and A(H3N2) are two viruses that commonly circulate in humans (H3N2).

Who Is at a Higher Risk of Developing Flu A?

Most people recover from the flu on their own. However, influenza and its complications can be fatal at times. The following people are at a higher risk of developing flu complications:

• Young children under the age of five, particularly those under the age of six months.

• Adults above 65 years.

• Nursing home and other long-term care facility residents.

• Women who are pregnant or who have given birth within the last two weeks.

• People who have a weakened immune system.

• American Indians.

• Individuals suffering from chronic illnesses such as asthma, heart disease, kidney disease, liver disease, and diabetes.

• People who are extremely obese, with a basal metabolic rate (BMI) of 40 or higher.

What Are the Symptoms of Flu A?

Unlike a common cold, the flu usually has a sudden onset of symptoms. The following are common symptoms of influenza infection:

• Coughing.

• Sneezing.

• A stuffy or runny nose.

• Body ache.

• Fever.

• Sore throat.

• Fatigue.

• Chills.

• Headache.

Symptoms of influenza A may resolve on their own. However, consult the doctor if the symptoms persist for more than a week without improvement. People who are at high risk of flu complications, such as those over the age of 65 or those with weakened immune systems, should seek immediate medical attention. The flu can be fatal in rare cases.

What Are the Causes of Flu A?

When an infected person coughs, sneezes, or speaks, the virus spreads through the air in droplets. A person can either directly inhale the droplets or pick up the germs from an object, such as a phone or computer keyboard, and then transfer them to the eyes, nose, or mouth.

People infected with the virus are likely contagious from the day before symptoms appear until five days after they appear. Children and those with compromised immune systems may be contagious for a slightly extended period.

Influenza viruses are constantly evolving, with new strains appearing on a regular basis. If a person has had influenza in the past, their body has already produced antibodies to combat that particular strain of the virus. Suppose future influenza viruses are similar to those they have encountered previously, either by having the disease or by being vaccinated. In that case, those antibodies may prevent or lessen the severity of infection. However, antibody levels may reduce with time. Furthermore, antibodies against previously encountered influenza viruses may not protect them from new influenza strains, which can be very different viruses from what they had once.

How Is Flu Diagnosed?

The doctor will need to test for the influenza virus before treating the condition. The rapid molecular assay is the preferred test. The physician will swab the nose or throat during this procedure. Within 30 minutes or less, the test will detect influenza viral RNA (ribonucleic acid). However, because the results are not reliable, the doctor may have to make a diagnosis based on the symptoms or other flu tests.

What Are the Treatment Options for Flu A?

With adequate rest and fluid intake, influenza A symptoms may resolve on their own in some cases. In other cases, the doctor may advise taking antiviral medication to combat the infection. Typical antiviral prescriptions include Peramivir, Zanamivir, and Oseltamivir. These medications, known as neuraminidase inhibitors, slow the spread of the influenza virus from cell to cell, thus slowing the infection process. Although these medications are effective, they can cause side effects such as nausea and vomiting. If a person starts experiencing any of these symptoms or if the condition worsens, they must stop taking the medication and see the doctor right away. A new medication called Baloxavir marboxil, developed by a Japanese pharmaceutical company was approved by the United States food and drug administration (FDA). This antiviral medication works to prevent the influenza virus from replicating. Over-the-counter medication can also help with flu symptoms. One must stay hydrated to help loosen mucus in the lungs and strengthen the immune system.

How Can Flu A Be Prevented?

The methods of preventing the spread of this disease include:

• The best way to avoid the flu is to get vaccinated every year. Each flu shot protects against three to four different influenza viruses during the flu season that year.

• Handwashing on a regular basis.

• Avoidance of large crowds, particularly during a flu outbreak.

• When a person coughs or sneezes, they must cover their mouth and nose.

• If a person gets a fever, they must stay at home for at least 24 hours after it goes away.

Conclusion:

Type A influenza is a contagious viral infection that, if left untreated, can lead to life-threatening complications. While some cases of this infection may improve without the prescribed medication, a trip to the doctor is advised. Patients must not attempt to self-diagnose the condition. The flu can look like a common cold, but it can cause symptoms to worsen. If a person has caught the flu, they must consult their doctor to discuss treatment options.