H3N2 on rise, behind long cough-cold spell

Kolkata: A prolonged cold-and-cough could be the H3N2 virus, currently in circulation in the city. Hospitals and labs in Kolkata are seeing a rising number of patients testing positive for H3N2. The cases started trickling in around mid-June, and now, the numbers are multiplying fast.Common during both monsoon and winter months, H3N2 is a subtype of influenza A, like H1N1. Though less virulent than H1N1 (swine flu), this respiratory virus is notorious for causing nagging, prolonged bouts of cough and cold in most affected individuals."We detected around 23 cases from mid-June till the beginning of this week. And the number is going up, with about 20 more positive cases being detected in our lab in the past three-four days," said microbiologist Bhaskar Narayan Chaudhuri, head of the lab at Peerless Hospital.Hospitals reported that while most cases are mild, the detection is mostly from admitted patients who came with complaints like fever, cough, body ache, fatigue, and sore throat. "Last year, we did not get a significant number of H3N2 cases. But there is a marked rise in this upper respiratory infection now. Among the positive samples, many are from children and the elderly," said molecular pathologist Abhirup Sarkar, lab director at Suraksha Diagnostics.Sources said some labs are getting as many as seven H3N2-positive cases in 10 flu samples. What concerns doctors is that while this virus causes mild illness in most cases, it could trigger serious illness in patients under two, and the elderly with comorbidities.Health experts said both H1N1 and H3N2 are subtypes of the influenza A virus, but they differ in their specific characteristics and how they affect humans. H1N1 caused a pandemic in 2009, followed by several surges over the years in India."H3N2 is a common cause of seasonal influenza, with peaks during the monsoon months and also during winter. Both viruses can cause similar flu-like symptoms, but H3N2 is often associated with higher-grade fever and leucopenia or low WBC count. H1N1 may be linked to more prominent respiratory issues, including viral pneumonia, and gastrointestinal issues. H1N1 usually causes more severe infections than H3N2, and mortality is higher in the former," Chaudhuri added.Narayana Hospital Howrah detected the virus in two male patients who are above 60. "We are concerned about this virus because it can cause severe disease in some, requiring hospitalisation. Currently, there is no vaccine available against H3N2," said Rasika Avinash Deshmukh, microbiologist and infection control officer at the Howrah hospital.Doctors said the route of transmission of this virus is through respiratory droplets, and cough etiquette, mask-wearing, and hand hygiene are some preventive measures.