An international collaboration of researchers including Felicia Goodrum of the University of Arizona's immunobiology department has studied how a human herpes（疱疹） virus carried by the majority of the population packages its genetic information during infection. The discoveries improve the chances of developing more targeted therapies in place of existing drugs, which do not always work or come with side effects.

Experts estimate that 60 to 90 percent of the world's population carry the human cytomegalovirus（巨细胞病毒）, or CMV, which is one of the eight herpes viruses that infect humans.

In healthy individuals, the virus lies dormant and does not cause overt disease. However, it poses a significant risk when contracted by unborn children -- whose immune system has not matured yet -- and individuals with compromised immune function.

CMV is the leading cause of birth defects resulting from any infectious agent. It affects one in 150 births in the US and most commonly results in hearing loss, but can also cause cognitive or physical anomalies and cerebral palsy. Once infected, the virus stays in the body for life and flares up only when the immune system is suppressed, for example in AIDS patients, transplant patients and cancer patients undergoing intensive chemotherapy（化学疗法）.

For the study, published in the scientific journal Proceedings of the National Academy of Sciences (PNAS), Goodrum teamed up with collaborators in Germany and Israel.