Chink in the armour of viral ”tummy bug” identified

December 24th, 2008 - 2:54 pm ICT by ANI  

London, Dec 24 (ANI): Scientists have taken a major step towards the treatment for the dreaded ”viral tummy bug” or rotavirus after finding a chink in the armour of these rotaviruses.

Rotaviruses are highly infectious viruses, which are the leading cause of severe diarrhoea in young children and are responsible for thousands of hospitalisations in the developed world, and hundreds of thousands of deaths each year in developing countries.

Researchers at Griffith Universitys Institute for Glycomics conducted the study in collaboration with colleagues at the University of Melbourne.

Professor Mark von Itzstein, Institute Executive Director, said that their findings demanded a total rethink of how these viruses work.

“Rotaviruses are thought to infect the bodies by sticking to certain types of sugars called sialic acids on the surface of our stomach cells. They then enter cells and reproduce rapidly, causing illness,” Nature quoted him as saying.

He added: “Rotavirus vaccines are still in their infancy, as problems emerged with the first vaccine that was trialled a number of years ago. While other vaccines are now in clinical use, new directions are required in the development of potential drugs to prevent or treat this deadly virus.”

For better understanding of how carbohydrates are involved in rotavirus infection, he said, they had focussed on treating mammalian cells with a protein called sialidase.

Sialidase cuts the surface sugars thus making it impossible for the virus to attach.

Earlier, majority of scientists concluded that some viruses depend on sialic acid to infect the body, while others were thought to cause infection independent of sialic acid.

“Unsuccessful attempts to reduce rotavirus infection with this treatment led scientists to group rotaviruses into two classes: ‘’sialidase-sensitive” and ‘’sialidase-insensitive” strains,” said von Itzstein.

For the study, the researchers used nuclear magnetic resonance spectroscopy, 3D modelling and cell-based assays, for examining how the virus and host cells interact with each other.

“We found that a human strain previously through insensitive to sialidase does in fact recognise and bind to sialic acid, but it is a sialic acid not accessible to sialidase treatment.” said von Itzstein.

He added: “This reveals that there is a common chink in the armour of these rotaviruses. This discovery is the first step in designing a broad-spectrum drug able to exploit this weakness to combat many types of human and animal rotaviruses.”

The study is published in the world-leading Chemical Biology journal Nature Chemical Biology. (ANI)

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