[NEW DELHI] Scientists have cracked the mystery of how the Japanese encephalitis virus leaves many infected children impaired for life with brain and nerve problems.
The Japanese encephalitis (JE) virus is spread by mosquitoes and is closely related to the West Nile virus.
About 70 per cent of children infected with the virus die or experience lifelong suffering from paralysis, seizures or mental retardation.
Now, scientists from the National Brain Research Centre (NBRC) in Manesar, India, have shown how the JE virus damages the brain permanently.
NBRC scientist Anirban Basu says the virus not only kills the brain cells, but also stem cells that give rise to new brain and nerve cells. "It is a double hit. Not only are the neurons (nerve cells) dying, but also the stem cells that give rise to the neurons," Basu told SciDev.Net.
"Children are permanently impaired as there is deficit of neuronal stem cell population," he adds.
Basu and colleague Sulagna Das, whose findings will be published in an upcoming issue of the Journal of Neurochemistry, found that the JE virus interferes with a specific stage of stem cells division, preventing their proliferation.
This discovery could help scientists devise a treatment strategy based on improving ways to rescue the nerve and stem cells from death and help them proliferate.
In the February 2008 issue of the same journal, Basu and colleagues reported that minocycline, a derivative of the common antibiotic tetracycline, protected JE-infected mice from brain and nerve damage. "The data suggests that minocycline may be a candidate to consider for human trials for JE patients," write the authors.
JE is a neglected disease of poor countries, with few scientists working on it, says Basu.
The US-based non-profit organisation PATH says JE infects over 50,000 people in Asia, mostly children who are more vulnerable to the virus. An estimated three billion people live in JE-endemic areas.
There is no specific treatment for JE infection, and public health authorities rely on mosquito control measures and vaccinating children in endemic areas. Of the two JE vaccines available, one made from inactivated mouse brain tissue is expensive and the other, a Chinese vaccine made from a live, weakened virus, has shown promise in clinical trials in China and Nepal.
Link to abstract in the Journal of Neurochemistry
Journal of Neurochemistry (2008), early online publication.