H3N2 flu: effective means of diagnosis, risk factors | Health

H3N2 flu The virus has increased the number of hospitalized cases in and around Delhi and although most of the 1,000 cases detected in the country have been mild, the government advisory has warned people to take precautions like cleanliness , crowding prevention and hand hygiene. Children under 6 and adults over 65 have been advised to take special precautions as they are part of the vulnerable group. (Also read: H3N2 flu: Signs and symptoms of serious illness to watch out for)

Respiratory diseases could be on the rise this spring due to a multitude of factors such as pollution, festive gatherings, poor hand hygiene and declining immunity, among others. It is important to distinguish the symptoms of H3N2 flu from those of Covid because while the latter is supposed to last 2-3 days and the patient recovers quickly, H3N2 and H1N1 can extend for a few weeks and can even have more chances of leading to pneumonia or a secondary bacterial infection, experts say.

“Currently, about 30% of patients present with symptoms of upper or lower respiratory problems. Symptoms are more or less the same for any viral illness: sore throat, dry cough, headache, myalgia, diarrhea, the only difference is that in the current clinical scenario Covid symptoms barely last 2-3 days and the patient recovers quickly with no hassle and no major treatment. longer for a few weeks and have a higher chance of catching pneumonia or a secondary bacterial infection. Regardless of the virus, if there is a major comorbid factor, there is a higher risk of morbidity and mortality,”

Dr Samrat Shah, Senior Internal Medicine Consultant, Sir HN Reliance Foundation Hospital, told HT Digital.

Elaborating on the causes of the increase in respiratory infections, Dr Shah said: “In the current scenario, all viral respiratory diseases, be it influenza A-H3N2, H1N1 variant, new coronavirus 19 and the omicron subvariant, these are increasing steadily, due to host of environmental factors.Some of the host factors are avoidance of face masks, a casual attitude towards general health, poor hygiene of hands and more social gatherings.Some of the environmental factors contributing to the increase in cases are poor air quality and overbuilding The only way to prevent this complication of the flu virus is to vaccinate once a year with the quadrivalent influenza vaccine.

Why there is an upsurge in flu infections and hospitalizations in India

“India is currently experiencing an upsurge in influenza virus infections due to H3N2. Influenza A viruses infect humans and many different animals. The emergence of a new and very different influenza A virus capable of ‘infecting people and having sustained human-to-human transmission, can cause an influenza pandemic and is therefore of critical public health importance,’ says Dr Sunita Kapoor, director and consultant pathologist at the City X-ray & Scan Clinic .

“Type A influenza viruses are classified into subtypes based on combinations of different virus surface proteins, hemagglutinin (HA) and neuraminidase (NA). Current influenza virus subtypes A that regularly circulate in humans include A(H1N1) and A(H3N2) “In years when H3N2 is the predominant strain, there are more hospitalizations. Human infections are mainly acquired through direct contact with infected animals or contaminated environments, these viruses have not acquired the capacity for sustained transmission between humans,” adds Dr Kapoor.

Who is at risk for the H3N2 flu virus?

Dr Kapoor says young children and the elderly are among those most at risk from this virus, while pregnant women, people with weakened immune systems, chronic illnesses and travelers may also be at risk. this virus.

Here are those who are at risk of contracting the H3N2 flu virus:

– Young children under 2 years old

– Adults over 65

– Residents of retirement homes and other long-term care facilities

– People who are pregnant or planning to be pregnant during flu season

– People with a weakened immune system

– People with chronic diseases, such as asthma, heart disease, kidney disease, liver disease and diabetes

– Healthcare workers performing aerosol-generating procedures.

– Travelers to countries and people living in countries with bird flu epidemics

Diagnosis of the H3N2 virus

According to Dr. Kapoor, influenza virus detection techniques have been classified into four categories:

– Traditional methods, eg serological methods of viral culture, eg immunofluorescence tests, complement fixation, immunodiffusion test, virus neutralization method, haemagglutination method, rapid antigen test.

– Advanced Quick Methods which include NAT (nucleic acid testing) like RT PCR, multiplex PCR, nucleic acid sequence based amplification (NASBA) and conventional PCR.

– Bio-detection methods which include optical biosensors, giant magnetoresistance biosensors, aptamer-based biosensors and electrochemical biosensors

Nucleic Acid Based Tests

“Nucleic acid (NAT) tests use PCR and virus-specific RNA or DNA/genetic material sequences instead of viral antibodies or antigens. These are much more sensitive and specific than serological tests and can diagnose viruses in many previous clinical specimens.An antibody-based test is time-consuming because the human body cannot produce antibodies instantly at a detectable level.Therefore, NAT can overcome this limitation of serological methods. Most of these methods take 2-4 hours to complete the detection,” says Dr. Kapoor.

RT-PCR

This technique is considered the most powerful tool for the detection of influenza virus. Nested primers are used to detect and subtype influenza viruses. The results of this test show extremely high sensitivity and specificity, the best of all traditional detection approaches.

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