May 16, 2007 -- An ongoing effort to identify the microorganisms that make us sick has discovered a new virus potentially linked to unexplained respiratory infections.

Clinicians can typically use a patient's symptoms to determine that a virus is the likely culprit in a respiratory infection. However, even with advanced testing they still can't pin the blame on a particular virus in roughly one-third of all such infections.

Scientists can't yet prove that the new virus, known as the WU virus, is making patients sick. But senior author David Wang, Ph.D., of Washington University School of Medicine in St. Louis, is suspicious enough that he's started follow-up studies.

"We've completed the first step required to link the WU virus to disease," explains Wang, who is an assistant professor of molecular microbiology. "First, you have to detect the potential pathogen in someone who's sick. Then you have to develop a way to grow the new microorganism in the laboratory. Finally, you have to show that you can make an animal model sick by exposing it to the microorganism."

These steps, known to microbiologists as Koch's postulates, were established in the 19th century. Wang says they represent the scientific "gold standard" for linking a microorganism to disease, but as technology has made it possible for scientists to identify viruses before culturing them, the postulates haven't always been followed. For example, scientists have long accepted the hepatitis C virus as a cause of disease, but they only successfully grew it in the lab in the past year.

The research appeared in Public Library of Science Pathogens on May 4. It was supported in part by a grant from the Midwest Regional Center of Excellence for Biodefense and Emerging Infectious Disease Research, a multi-institutional research center anchored at Washington University.

For the study, collaborators at The Royal Children's Hospital in Melbourne, Australia, provided samples from p
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Contact: Michael C. Purdy
purdym@wustl.edu
314-286-0122
Washington University School of Medicine
16-May-2007