When the temperature drops and the sniffles start, you know flu season is around the corner. But did you know that the flu isn’t just a one-size-fits-all illness?
The flu actually comes in four different types.
Here’s a quick look into each of them.
What is flu A, B, C, and D?
Influenza, commonly known as the flu, is a contagious respiratory illness caused by four main types of influenza viruses: A, B, C, and D.
Influenza A
Influenza A viruses are the most concerning because they can infect both humans and animals, including birds and pigs. They’re the primary cause of flu pandemics due to their ability to mutate rapidly. They can create new strains that can spread easily and against which people often have little to no immunity.
Seasonal flu outbreaks caused by Influenza A can vary in severity, and certain strains, like H1N1 or H3N2, are responsible for significant epidemics.
Influenza B
Unlike influenza A, influenza B infects only humans. While it’s less versatile, it’s still a major cause of seasonal flu epidemics and can cause serious illness, especially in vulnerable groups like young children and the elderly.
Influenza B mutates more slowly than Influenza A, but its persistence in annual flu seasons makes it a significant public health concern.
Influenza C
This type of influenza is less common and causes milder respiratory symptoms. Influenza C outbreaks are sporadic, and they don’t lead to widespread epidemics like influenza A or B.
Influenza D
Since influenza D is primarily found in cattle and has not been shown to infect humans, it’s less of a concern for public health. Even so, understanding the transmission among animals and the potential for cross-species transmission could have implications in case there’s an influenza D outbreak among humans in the future.
How are flu A, B, C, and D transmitted?
There are three ways that these viruses can spread.
1. Through respiratory droplets
Flu types A, B, and C spread through tiny respiratory droplets released when an infected person does any of the following:
- Coughing
- Sneezing
- Talking
These droplets can travel through the air and land in your mouth or nose if you’re nearby. If inhaled, the virus can infect your respiratory system.
2. By touching contaminated surfaces
All flu types can spread through indirect contact. This happens when someone touches a surface or object contaminated with flu viruses, such as:
- Doorknobs
- Phones
- Handrails
After coming into contact with any of these surfaces, you may get infected with either influenza A, B or C if you touch your:
- Mouth
- Nose
- Eyes
3. Animal-specific transmission
While types A, B, and C can infect humans, influenza D primarily affects cattle by spreading among animals in close contact, often through respiratory secretions or contaminated environments.
What are the symptoms of flu A, B, and C?
Flu viruses cause a range of symptoms, and each varies in severity depending on the type. While influenza A and B are the most common and impactful on humans, influenza C causes milder symptoms, and Influenza D doesn’t infect humans.
Here’s a breakdown of the symptoms associated with each type.
Symptoms of influenza A
Influenza A is often the most severe type of flu, and its symptoms include:
- High fever
- Severe muscle aches
- Persistent dry cough
- Intense headaches
- Extreme fatigue
- Sore throat
- Runny or stuffy nose
- Chills and sweats
- Shortness of breath
- Loss of appetite
Symptoms of influenza B
Influenza B symptoms are less intense than those of influenza A. These include:
- Fever
- Chills
- Fatigue
- Sore throat
- Runny nose
- Body aches
- Mild cough
Symptoms of influenza C
Since influenza C results in milder respiratory illnesses compared to A and B, you may experience the following symptoms if you get infected with this virus:
- Mild fever
- Runny or stuffy nose
- Mild cough
- Sore throat
- Fatigue (less severe than Influenza A or B)
- Occasional headaches
How can you prevent flu A, B, and C?
Here are different things that you can do to prevent yourself and other people from getting infected with the flu.
- Getting your annual quadrivalent vaccine. These vaccines protect against four different flu viruses, including two strains of Influenza A and two strains of Influenza B. Flu vaccines are updated annually to target the most common and dangerous strains circulating that season.
- Regular handwashing. Wash your hands frequently with soap and water for at least 20 seconds. This simple step removes germs and prevents the spread of the virus.
- Using hand sanitizer. When soap and water aren’t available, use a hand sanitizer with at least 60% alcohol to kill germs effectively.
- Avoiding close contact with sick individuals. Keep your distance from people who are coughing, sneezing, or showing flu symptoms to minimize your exposure.
- Covering your mouth and nose. Practice good respiratory hygiene by covering your mouth and nose with a tissue or your elbow when coughing or sneezing to prevent spreading respiratory droplets.
What are the treatments for flu A, B, and C?
Here are different methods on how each flu type is addressed.
- Antiviral medications. Medications like Oseltamivir (Tamiflu) and Zanamivir (Relenza) are effective in treating Influenza A and B. These drugs work best when started within 48 hours of the onset of symptoms, as they help reduce the severity and duration of the illness. Antivirals are especially important for high-risk groups, such as:
- The elderly
- Young children
- Those with underlying health conditions
- Supportive care. For mild symptoms that don’t require antiviral treatment, here are helpful ways to treat the flu.
- Get hydrated
- Rest
- Take over-the-counter medications or pain relievers
What are the complications associated with flu A, B, and C?
While complications in influenza C are rare due to its generally milder symptoms, the complications from influenza A and B may become severe enough to require hospitalization. These complications include:
- Pneumonia
- Bronchitis
- Worsening of chronic health conditions
How do you differentiate the flu types from other respiratory infections?
It can be challenging to differentiate the different types of influenza from other respiratory infections because of the symptom overlap.
Without testing, it’s nearly impossible to tell whether a person’s symptoms are caused by the flu, another viral infection or even a bacterial illness. That said, here are different tests you can take to pinpoint the cause of your symptoms:
- Polymerase chain reaction (PCR) tests. PCR testing is a highly accurate method for identifying specific influenza viruses (A, B, C, or D) and differentiating them from other respiratory pathogens like COVID-19 or respiratory syncytial virus (RSV). These tests detect the genetic material of the virus and are often used in hospitals and clinics.
- Rapid antigen tests. While less sensitive than PCR tests, rapid flu tests can quickly confirm the presence of influenza A or B.
Frequently asked questions
What distinguishes flu types A, B, C, and D?
Flu A and B are responsible for seasonal epidemics, with A being more severe. Flu C causes mild respiratory illness, not epidemics. Flu D primarily affects cattle and isn’t known to infect humans.
How are flu viruses A and B similar?
Both flu viruses A and B can cause seasonal epidemics and are responsible for the seasonal flu vaccines developed each year to protect against the most common strains.
Can humans contract flu type D?
Currently, flu type D is not known to infect humans as it primarily affects cattle.
Why do flu vaccines focus on types A and B?
Vaccines focus on flu types A and B because these types are responsible for seasonal flu epidemics that pose significant public health risks. Vaccination aims to reduce the incidence of these more severe strains.
Key takeaway
Flu viruses A, B, C, and D each have distinct characteristics, with A and B being the primary culprits behind seasonal flu epidemics.
Influenza A is more severe and can lead to pandemics due to its ability to infect both humans and animals, while Influenza B affects only humans and typically causes milder outbreaks. Influenza C results in mild respiratory illness and rarely leads to complications, while Influenza D primarily affects cattle and poses no risk to humans.
If you’re experiencing flu-like symptoms, determine your condition by taking a quick antigen test that can identify if you have influenza A, influenza B, or COVID-19. Shop at our online store here and have it shipped straight to your doorstep.
