Swine flu: What explains sudden spurt in H1N1 human influenza deaths in India

By Syed Akbar
Hyderabad, Aug 10: Scientists and health experts are baffled over the sudden swine flu deaths in the country, even as the National Institute of Virology has clarified that the novel H1N1 virus that causes human influenza has not mutated in India to become more aggressive.

Swine flu has been in existence in the country for the past five months without any fatalities. But in the last one week there have been six deaths, forcing scientists and health experts to think whether the virus had mutated in the country to take a virulent form. Some believe that the novel H1N1 virus is now in the second
phase of manifestation as the human influenza viruses normally do. The Spanish flu virus did the same in early 19th century killing millions of people worldwide.

"We have been monitoring the virus from different human samples. But so far we have not found any mutation or change in the virus. The virus currently present in the country is the same as found in Mexico, USA and other parts of the world," Dr Akhilesh C Mishra, director of NIV, Pune, told this correspondent.

Asked about the sudden swine flu deaths in the last one week, Dr Mishra attributed it to the "wide profiling system" now adopted by health authorities. "Earlier, we used to screen only those coming from other countries. Now we are screening the local public too. This has led to a sudden spurt in the number of cases.
And this explains the deaths too," he clarified.

But senior geneticist Dr M Khaja emphasises the need for a relook at the virus. "All through the history the influenza virus has been mutating. Even the present novel H1N1 virus is a mutant one. There are chances of it mutating further in a country like India with vast population. Swine flu virus is capable of leading to
secondary infection, both viral and bacterial," he said.

Even as local scientists differ on whether the virus has mutated or turned aggressive since temperatures have gone down because of monsoon, American researchers have unravelled the mechanism the human influenza
virus adopts to kill its host.

Swine flu virus is capable of binding deeper into the cells of lungs and stomach, unlike other influenza viruses. "There are slight differences in the way different flu proteins bind to receptors in lungs. Since the swine flu virus binds deeper in the lung's trachea, bronchi and bronchioles, it causes breathing problems,
which ultimately lead to death. The virus is also capable of replicating faster and causing more damage than other influenza viruses. Different patients react differently to the virus. This explains the death of some swine flu patients and survival by others," said US-based senior researcher Dr G R Reddy.

While other influenza virus do not touch the stomach, the novel human influenza virus binds with the stomach lining and intestines. This causes diarrhoea, vomiting and nausea in some patients suffering from swine flu.