Influenza Type A And B: Differences, Symptoms, Treatment And Prevention

Wednesday, May 13, 2020, 11:43

Influenza, commonly known as flu is a viral respiratory infection caused by different flu viruses. This contagious infection usually spreads through respiratory droplets when a person who is infected with the flu virus coughs or sneezes. Influenza most commonly occurs during the fall and winter months.

There are different types of influenza viruses that belong to the family Orthomyxoviridae. There are four types of influenza virus - type A, B, C and thogotovirus, out of them only type A and B are the common influenza viruses that mostly affects humans [1].

In this article, we will discuss the differences between influenza type A and B viruses.

What Is Influenza Type A Virus? [2]

Influenza A viruses are single-stranded negative-sense RNA viruses that have a genome consisting of eight segments. The subtypes of influenza A viruses are H1N1, H3N2 and rarely H1N2 that infects humans. The subtypes are divided on the basis of two proteins on the surface of the virus i.e hemagglutinin (H) and neuraminidase (N). There are about 18 different hemagglutinin subtypes (H1 through H 18) and 11 different neuraminidase subtypes (N1 through N11).

There are about 198 different subtype combinations of influenza A, only 131 subtypes have been detected [3].

Type A flu virus can infect humans and animals, and usually wild birds are the hosts of this type of virus. The virus multiplies in the digestive tract of the birds and the infection is usually asymptomatic. In wild aquatic birds, all influenza A subtypes have been found (16 species of H and 9 N). Influenza A viruses also infect pigs, horses, poultry, dogs and occasionally sea mammals.

Influenza type A viruses are primarily transmitted through the faecal-oral route. These viruses are capable of causing a pandemic.

What Is Influenza Type B Virus?

Influenza B viruses are negative-strand RNA viruses with a genome consisting of eight segments. Since, 1940, the virus has been detected in the human population, they are the primary hosts of influenza B viruses. Influenza B infection has been reported in marine mammals as well.

The influenza B viruses are not divided into subtypes, but there are two lineages of this type B virus - Victoria and Yamagata. Influenza B virus do not cause a pandemic[4].

The mutation of the virus happens more slowly as compared to influenza A virus, however, the mortality rates of type B virus is higher among the elderly.
The influenza type B virus is primarily transmitted through inhalation of respiratory droplets containing the virus.

Both the influenza A and B viruses are spherical or filamentous in shape, with spherical forms having a diameter of 100 nm and the filamentous forms are 300 nm in length [5].

Symptoms Of Influenza A and B Viruses

• Fatigue
• Cough
• Headache
• Nasal congestion
• Sore throat
• Body aches
• Fever
• Chills
• Vomiting
• Diarrhoea
• Shortness of breath
• Chest pain
• Loss of consciousness

Prevalence Of Influenza A and B Viruses

According to a study published in PLOS One, approximately 75 per cent of confirmed cases are of influenza A virus, and influenza B virus is responsible for about 25 per cent of confirmed cases [6].

Contagiousness Of Influenza A and B Viruses

Both influenza type A and B are highly contagious. People who are infected with Type A and B viruses can spread the virus to others from up to about six feet away through cough, sneeze or talk. These water droplets can either fall in the mouth or nose or it can be inhaled by a person who comes in contact with the infected person [7].

People with influenza are extremely contagious in the first three to four days after their illness starts. Also, healthy adults can transmit the virus to others even before the symptoms appear and five to seven days after falling sick.

Who Are At A Risk Of Influenza A and B Viruses?

• Pregnant women
• Children younger than five
• People with certain chronic medical conditions
• Adults aged over 65.

Diagnosis Of Influenza A and B Viruses

The doctor will conduct a physical examination and check for symptoms of influenza virus. The polymerase chain reaction (PCR) test is done to detect the strain of the influenza viruses [8].

Treatment Of Influenza A and B Viruses

The treatment consists of home remedies and antiviral medications.

Home Remedies

• Drink plenty of water and fluids
• Take proper rest
• Drink warm broth
• Salt water gargle to soothe sore throat
• Drink herbal tea
• Apply essential oils
• Eat a bland diet
• Steam inhalation

Antiviral Medications

Antiviral medications are prescribed by the doctor to reduce the complications and symptoms of influenza virus. The antiviral medications are oseltamivir, zanamivir, peramivir andbaloxavir marboxil that comes in the form of pill, liquid, inhalable powder and intravenous therapy.