Dual and Triple Infections in Influenza A and B Viruses - An Overview

Introduction:

Dual and triple infections involving both influenza A and B viruses are very rare and not impossible. Influenza A viruses are categorized into two groups, characterized by their surface proteins known as hemagglutinin (H) and neuraminidase (N). Influenza B viruses, on the other hand, do not have subtypes but are divided into two lineages, Victoria and Yamagata. Dual infections with influenza A and B viruses have been reported in several countries, including the United States, Japan, and Australia. Triple infections involving both influenza A and B viruses have also been reported but are even rarer. Triple infections occur when an individual is infected with two different subtypes of influenza A viruses and an influenza B virus at the same time.

What Are Dual Infections With Influenza A and B Viruses?

Dual infections with influenza A and B viruses refer to the simultaneous infection with two different strains of the influenza virus, one from the influenza A family and another from the influenza B family. Influenza A and B viruses are both highly contagious respiratory illnesses that can cause seasonal epidemics and occasional pandemics. When a person is infected with both influenza A and B viruses at the same time, it can make their illness more severe and increase the risk of complications.

Triple infections involving both influenza A and B viruses occur when an individual is infected with both influenza A and B viruses, as well as a third strain of the influenza virus. These infections are relatively rare but have been reported in some cases. Triple infections can occur when a person is exposed to multiple strains of the influenza virus at the same time or in quick succession. This can happen, for example, when there are multiple strains of the flu circulating in the community or when a person is exposed to the flu while they are already infected with one strain.

What Are the Causes?

Dual and triple infections involving both influenza A and B viruses occur when multiple strains of these viruses infect the person simultaneously or within a short period of time. The causes of dual and triple infections involving both influenza A and B viruses can include:

• Co-circulation of Multiple Strains: Throughout the flu season, various strains of both Influenza A and B viruses can be concurrently circulating within a given population, thereby raising the likelihood of multiple infections.

• Exposure to Infected Individuals: Close contact with infected individuals, especially in crowded settings such as schools or workplaces, can increase the risk of dual and triple infections.

• Weakened Immune System: Individuals with compromised immune systems, resulting from medical conditions or medications, may exhibit increased vulnerability to multiple infections.

• Travel: Travel to areas with high infection rates or exposure to people from different regions can increase the risk of dual and triple infections.

• Healthcare-associated Infections: Exposure to contaminated medical equipment or healthcare workers who are infected with different strains of influenza A and B viruses can increase the risk of multiple infections.

What Are the Signs and Symptoms?

The signs and symptoms of dual and triple infections involving both influenza A and B viruses are similar to those of a single infection with either virus but may be more severe. These symptoms may include:

• Fever.

• Cough.

• Sore throat.

• Runny or stuffy nose.

• Body aches.

• Fatigue.

• Headache.

• Chills.

• Shortness of breath.

How to Diagnose?

Diagnosing dual and triple infections involving both influenza A and B viruses involves a combination of medical history, physical examination, and laboratory tests. Here are a few tests used in the diagnosis of these infections:

• Rapid Influenza Diagnostic Test (RIDT): This test is a quick and easy way to diagnose influenza A and B infections in a doctor's office or clinic. It involves swabbing the nose or throat to collect a sample and testing it for the presence of influenza viruses. However, it may not always be accurate, especially in cases of dual and triple infections.

• Reverse Transcription-Polymerase Chain Reaction (RT-PCR): This test is a more accurate way to diagnose influenza A and B infections. It involves collecting a sample from either the nasal cavity or the throat and performing a test to identify the existence of viral RNA. It can also detect multiple strains of the virus.

• Serologic Testing: This test involves measuring the levels of influenza virus-specific antibodies in the blood. It can be used to confirm a diagnosis of influenza A and B infections and can also detect previous infections.

It is important to note that laboratory testing may not always be able to detect multiple strains of influenza A and B viruses. Therefore, clinical suspicion and a high index of suspicion are important for diagnosing dual and triple infections.

What Are the Complications of Dual and Triple Infection With Influenza A and B Viruses?

Dual infections and triple infections involving both influenza A and B viruses can increase the risk of complications compared to single infections. These complications can be more severe and longer-lasting and can include:

• Pneumonia: This is a serious complication that can develop when the flu virus spreads to the lungs. Symptoms are difficulty breathing, chest pain, and a persistent cough.

• Bronchitis: This is a condition marked by inflammation of the bronchial tubes, often leading to symptoms such as a persistent cough, wheezing, and difficulty breathing.

• Sinusitis: This is an infection of the sinuses that can cause facial pain, headaches, and congestion.

• Ear Infections: These can occur when the flu virus spreads to the middle ear, causing pain, fever, and difficulty hearing.

• Dehydration: This can occur when an individual with a dual or triple infection experiences fever, vomiting, or diarrhea, leading to a loss of fluids and electrolytes.

• Neurological Complications: In rare cases, dual or triple infections involving both influenza A and B viruses can cause neurological complications (seizures or encephalitis).

• Increased Risk of Mortality: There is an increased risk of death, especially in people with weakened immune systems, older populations, and children.

What Are the Treatment Options?

• Antiviral Drugs: Antiviral medications can have a notable impact in lessening the duration and intensity of the illness. However, their effectiveness is greatest when initiated early in the illness, preferably within 48 hours of the onset of symptoms. Commonly used antiviral medications for influenza include Oseltamivir, Zanamivir, and Peramivir.

• Rest: Rest is important to help the body recover from illness and conserve energy.

• Fluids: Staying hydrated by consuming an ample amount of fluids can aid in preventing dehydration and promoting the loosening of mucus.

• Fever-reducing Medications: Over-the-counter medications such as Acetaminophen or Ibuprofen are viable options for reducing fever and alleviating pain and discomfort.

• Cough Suppressants or Expectorants: Depending on the type of cough, a healthcare provider may recommend a cough suppressant or expectorant to help manage symptoms.

• Humidifier: A cool-mist humidifier or steamy shower can help to alleviate congestion and loosen mucus.

• Monitoring for Complications: In some cases, dual infections with influenza A and B viruses can lead to complications such as pneumonia, which may require additional treatment.

To prevent dual and triple infections that involve both influenza A and B viruses, it is essential to take precautionary measures that reduce the risk of contracting the viruses. These measures include getting vaccinated, practicing good hygiene, maintaining a safe distance from individuals who are sick, and staying home when experiencing illness symptoms.

Conclusion:

Dual infections and triple infections involving both influenza A and B viruses are conditions where an individual is infected with two or three different strains of the virus at the same time. These types of infections can be challenging to diagnose and treat and can lead to more severe symptoms and complications. Early treatment can help prevent serious complications and improve the chances of a full recovery.