H1N1 is mutating, turning deadlier

Mumbai: A preliminary study conducted by the state government into the deaths caused by the H1N1 influenza virus has revealed that the pathogen is now affecting patients more virulently and is producing newer reactions in the body. The study has also thrown up a perplexing fact--two-thirds of those suspected to have died of swine flu did not have the virus, despite showing all clinical symptoms.

Pathologists at the state-run Sassoon General Hospital in Pune took tissue samples from the bodies of the deceased to study the effect of the virus that attacks the respiratory tract. "Our doctors have concluded that the virus has undergone some genomic changes," said Dr Arun Jamkar, dean, BJ Medical College, Pune. A key discovery is that the virus, which was initially causing a bacterial infection, is now causing a more potent viral infection.

"The viral is now leading to a condition called hyalinisation of alvelar membrane, or thickening of the lung wall by deposition of proteins. Due to this, oxygen supply is severely affected, and even ventilators have been of little help," said Dr Pravin Shingare, joint director, Directorate of Medical Education and Research (DMER).

The state experts have found that the deaths between August 3 and 25 were largely due to formation of pus on the membrane lining the lungs. "During that period, deaths were caused mostly due to a secondary bacterial infection," said a professor who was involved in the study. But the deaths caused thereafter were the result of deposition of proteins on the membrane. "The deposition is more severe in the case of recent deaths. It leads to the thickening of the membrane, and therefore oxygen cannot not pass into the body at all," the professor said.

This finding has led experts to conclude that the virus has indeed undergone some changes and its anti-antigenicity is changing. But, the National Institute of Virology (NIV) in Pune has a different opinion. Director of NIV, Dr AC Mishra, said that his team is yet to record any change in the behaviour of the virus. "We still cannot say conclusively that the virus has mutated," he added.

Jamkar said that another interesting finding of the state experts has been that two-thirds of the influenza H1N1 patients who died actually tested negative for the virus. "As many as 36 suspected cases who died were later found negative for the virus," he said.

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