NEW DELHI: Specially designed mice, developed by Germany's top disease experts, will now help Indian scientists find the elusive Hepatitis C vaccine.

Annually, over two million Indians die due to chronic liver disease, 15 per cent of whom are infected with the Hep C virus while 45 per cent die due to the Hep B virus.

The mice, being developed by scientists from the Helmholtz Centre for Infection Research, will be infused with deadly strains of the Hep C virus found in India in July at the National Institute of Virology in Pune.

This, scientists say, will give them insight into how the human body tries to defend itself against the virus.

Interestingly, the mice have an immune system similar to that of humans and possess the ability to replicate the disease. They also have human liver cells which will help scientists infect it with the virus.

The lack of a robust small-animal model for Hepatitis C virus till now has hindered the discovery and development of novel drug treatments for the infection.

"After nearly five years of research and funding of $9 million, we have finally developed mice that have human liver cells. Indian scientists will infect them with different strains of the virus that is available in the NIV library. Over the next three years, with funding of $2.25 million, we will collect blood samples of Indian patients to analyse their immune cells," said Prof Rudi Balling, scientific director of the Helmholtz Centre for Infection Research.

What the team of Indian and German scientists want to know is: What are the different immune responses in children, pregnant women and the ageing population to the Hep C virus; why is it that only 20 per cent of those infected with Hep C go on to develop liver cancer; do some Indians have a genetic predisposition; whether poor nutrition, stress and lifestyle changes contribute to the virility of the virus; and how do different genes react on being infected?

According to Prof Balling, till now, scientists were severely limited in their capacity to study the path physiology of infectious diseases in man.

Laboratory animals have been used to model human diseases and have provided critical information that has advanced our understanding of several human conditions. However, for many human diseases, no adequate animal model has been identified since the pathology only develops in human tissues.

"Alternatively, when a model does exist, its widespread use is limited because of cost issues, poor accessibility or ethical considerations like in primate models. Given the technical feasibility of human immune system development in mice and the ability to generate human chimeric livers in mice, a mouse model is perfect for use in deciphering the human immune response to HCV infection," he added.

The Hep C virus causes infectious liver inflammation. Diagnosed during its acute state of infection, Hep C is curable in up to 80 per cent of cases. However, for 70-80 per cent of infected people, the disease leads to chronic infection.

WHO in 2000 reported that approximately 170 million people worldwide (3 per cent of the world population) are infected with Hep C. About 80 per cent of the newly infected people develop a chronic infection.