How To Diagnose Influenza A Subtype H3?

How To Diagnose Influenza A Subtype H3

Influenza A subtype H3 virus is indigenous to humans, swine, and wild birds. Some variants of this subtype usually cause flu-like Avian influenza or bird flu in humans, domestic birds, and animals.

Although cold and flu are different illnesses, they still possess similar syndromes. Thus, sometimes it’s getting harder to diagnose whether a human or animal is affected by the common cold or viral flu by signs and symptoms. A little difference is present in symptoms of cold vs influenza. Treatment might be irrelevant or negatively impact the body if the diagnosis is not done properly. Generally, 4 types of diagnostic tests are used to detect Influenza A Subtype H3, among them, the Antigen detection method & RT-PCR are the most common.

Comparison of Influenza A subtype H3 and common cold

In both cases, affected subjects suffer from fever, sneezing, runny or stuffy nose, muscle ache, headache, or, coughing sometimes. Cold symptoms are usually milder than viral flu and it takes 7-10 days for recovery.

Sign & symptomsInfluenza A Subtype H3Common cold
Onset of symptomsRapidGradually visible
Body achesUsual body pain; moderate to severeNo pain or mild to moderate pain
ShiveringQuite commonUncommon
Fatigue, WeaknessUsualOccasionally
SneezingOccasionallyVery common
Chest tightness, coldCommon symptoms; can be mild to severeMild to moderate
Stuffy noseVery rareMust be present
Sore throatIn rare casesCommon syndrome
HeadacheCommonRare cases
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Diagnostic tests for Influenza A subtype H3

To stop the outbreak of Influenza A subtype H3 virus, proper diagnosis is necessary. The diagnostic tests include:

  1. Antigen detection method: This test is done by collecting specimens from the respiratory tract and the antigen located at the surface of the virus starts reacting with the prepared antibody which indicates the presence of Influenza A (H3) virus.
    • Rapid Antigen test: It takes 20-30 minutes by visual color coding but there is a possibility for false positive or false negative results. This test cannot differentiate between Influenza A and Influenza B virus.
    • Immunoassay or Laboratory test: More specific than Rapid Antigen test and it can detect the actual type of influenza.
  2. Molecular Diagnostic method: This method is done by RT-PCR and it analyses the DNA or genetic materials of the virus, it can detect Influenza virus serotypes also by nucleic acid screening. But this test is designed to detect only specific variant’s subtypes.
  3. Viral Culture method: This is a time-consuming method and it’s not that popular for diagnostic or treatment purposes. Researchers use this technique as it provides vital information about the virus type and subtypes of the virus which can be used in the development of vaccines and anti-viral drugs.
  4. Serology method: This method continues with blood testing and detects the antibody activated against the Influenza virus. Decoding the antibody, the virus is determined.

Final thoughts

Rhinovirus, bacteria like catarrhalis, or S. pneumonia, or allergic reactions in the body can cause common colds. The cold caused by Rhinovirus recovers by itself by the body’s immune mechanism. Antihistamine drugs can also be effective for allergic colds. Sometimes physicians can prescribe antibacterial drugs for the common cold if it is caused by bacterial infection. As Influenza A subtype H3 is caused by viral infection, so no antibiotic can be effective against this flu. Proper diagnosis is necessary for appropriate treatment again this Influenza A subtype H3.

Pharmacologist I Researcher Research Coordinator Working site: Rajshahi Medical College Hospital, Rajshahi, Bangladesh Toxicology Society of Bangladesh