Swine flu virus undergoes deadly mutations: Study

Swine flu has been claiming one life a day on an average in the city for the past one month. A 55-year-old woman from Thakurli was the latest in line to fall prey to the deadly H1N1 virus taking the toll of deaths to 24 since January this year.

If the latest study by Massachusetts Institute of Technology (MIT) is to be referred to, then the frequent deaths could be a result of deadlier mutations in the virus strain last year as compared to 2009.

Since the last outbreak in 2009, the swine flu virus has undergone deadlier mutations in India, points out a research study by scientists published in the journal Cell Host & Microbe on Wednesday. The revelations contradict the stand taken by National Institute of Virology (NIV) in Pune and National Centre for Disease Control (NCDC) — premier research institutes in India.

Between 4,000-15,000 sequences of H1N1 virus were studied by researchers from around the world. They have criticised India for poor sample collection of sequences citing that while United States contributed to up to 38.4% of the sequences, India ranked a low 14th on the list contributing to less than 1.5% of the sequences.

"Despite the vastness of the Indian subcontinent, only two sequences have been deposited during 2014–2015 from India, suggesting poor surveillance and potentially limiting the response to a deadly outbreak," said Ram Sasisekharan, co-author of the study.

The researchers studied Hemagglutinin (HA) protein in Indian strains of 2014 and noticed changes in amino acids, which are basic building blocks of proteins as compared to amino acid structures observed in 2009 strains.

According to the NIV and NCDC, the H1N1 strain mutation mentioned in the MIT study virus has no relevance to current outbreak of 2015. "Recently, NIV has analysed six full genomes, which suggests absence of such mutations. We found that the strain analysed by the researchers and the sequence data of the original H1N1 virus as available with NIV did not show any of these mutations," said a press note released by NIV in reaction to the scathing reports.

The press note mentions nothing about the allegations of poor surveillance and monitoring by NIV as far as Indian outbreaks are concerned. "We have submitted our clarifications to the union health ministry and cannot comment any further," said Dr MS Chadda, deputy director, NIV.

However, with the number of infected cases and deaths increasing, doctors suspect the cause to be a more virulent strain lurking in the air. Since January, the union health ministry has confirmed that 26,000 cases have been detected in India, of which 1,482 persons have died, making it the most deadly outbreak in the last five years.

The H1N1 virus is air-borne and enters through the nasal route into the human body. Certain proteins or antigens on the surface of the virus cell attack the healthy cells in the body by binding on to the receptor binding sites of the healthy cells. "The virus and the human cell work on the lock and key mechanism. The MIT study shows that the amino acid changes in the strain of 2014 have possibly led to better binding capacity of the virus to the human cells. This may be leading to increased severity of the disease in patients," said Dr Om Shrivastav, infectious diseases consultant at Jaslok Hospital.

Dr Pradip Awate, Maharashtra's epidemiology cell in-charge underplayed the criticism of poor surveillance practices. He said, "We are relying on inputs from the NIV and the NCDC which have confirmed that there is no change in the genetic structure of the H1N1 virus in the state or country."

Dr Abhay Chowdhary, director, Haffkine Institute in Parel, said, "The study is significant and it might be true that the H1N1 may have undergone mutation but that does not change the treatment protocol. The antiviral medicines are still working and we have to focus on preventive measures."