Viruses are less resilient than we have presumed, a research group headed by Israeli scientists is claiming.

"We thought that viruses evolved for millennia to optimise their reproduction, but this isn't true," said Hebrew University professor Yaakov Nahmias, who led the study.

He said the research showed that human cells fought infection by adjusting viruses' metabolic processes.

In his experiment he found that blocking the glucose metabolism was detrimental to the hepatitis C virus (HCV), while blocking its lipid metabolism had the reverse effect.

Together with scientists from other institutions in Israel, America and Germany, Dr Nahmias used laboratory models of the human liver for their research and validated some of their findings in a small group of patients with hepatitis C. They published the research in the journal Nature Chemical Biology.

"This is the first indication that our cells can block replication of Flaviviridae viruses like HCV and Zika by denying them from critical building blocks they need to survive," Dr Nahmias said.

He said he believed doctors would be able to use this line of research to prescribe the right medicines to strengthen patients' bodies against viruses.

Jörg Timm, a co-author of the study from the Institute of Virology at the University of Düsseldorf, said the research "went against our common understanding of viruses as expert metabolic engineers, suggesting new avenues to target virus infection".

Oren Shibolet of Tel Aviv Sourasky Medical Centre and Tel Aviv University expressed hope that "the same methodology can be applied to study the metabolic regulation of liver cancer and other infections, to possibly identify new therapeutic targets".