Study: Anti-virals could worsen a disease

AUSTIN, Texas, Jan. 14 (UPI) -- Researchers at the University of Texas at Austin suggest anti-viral drugs may have the potential of making a virus more virulent.

The researchers raise the possibility an anti-viral drug -- drugs designed to kill viruses by causing their nucleic acid to mutate -- could make a disease worse.

Jim Bull said although the researchers did not question that extremely high mutation will lead to viral extinction on the whole, they say their research raises the specter that forcing viruses to undergo rapid mutations could, if the mutation rate is not high enough, accidentally lead to well-adapted "super viruses."

"This work questions whether the practice of 'lethal mutagenesis' of viruses works as predicted," Bull said in a statement.

The researchers tested the model of viral evolution at high mutation rates by growing a DNA virus in the presence of a mutagenic agent. The current accepted model predicted the virus would not be able to handle the high mutation rates and would eventually die off.

However, the study, published in Genetics, proved the model false, as the virus actually increased its fitness at elevated mutation rates. The scientists found molecular evidence that rapid mutations had two effects. The first effect of most mutations, which was expected, was that they killed or weakened the virus. The second effect of some mutations, but was that they actually helped the virus adapt and thrive.