UCI Scientists Create Simpler Test for Virus

A fast, simple method for diagnosing the West Nile virus, a strain of mosquito-borne encephalitis, has been developed by a team at UC Irvine’s College of Medicine.

The test uses a technique that can detect the virus in small samples of spinal fluid. Because the test is relatively uncomplicated and takes only five hours to provide an analysis, it would help in diagnosing and treating the disease, according to physicians at the National Institutes of Health and UCI. The findings appear in the current issue of the Lancet, posted on the magazine’s Web site Thursday.

“A rapid diagnosis of West Nile virus . . . allows physicians to offer early intervention with antiviral therapy, and may help authorities prevent further spread of the disease,” said Dr. Gerald D. Fischbach, director of the National Institute of Neurological Disorders and Stroke.

Encephalitis is a brain inflammation that can result from virus infections often carried by birds and horses, then transmitted from them to humans by the bite of a mosquito. It can also be caused by bacteria or exposure to parasites or chemicals.

“We think this test can be used to diagnose encephalitis infections and quickly treat patients who have been infected by the West Nile virus without having to send samples to faraway laboratories,” said Dr. W. Ian Lipkin, professor of microbiology and molecular genetics at UCI.

The test was developed from work done by Lipkin and Thomas Briese, an assistant professor of neurology and microbiology, during an outbreak last year of viral encephalitis in New York City. At the time, Lipkin and his colleagues were credited with isolating the virus and determining that it was the West Nile variety.

The West Nile virus can be present in people without causing symptoms, and many people get the disease and recover. The elderly, the very young and those with compromised immune systems are most vulnerable to it.

Before 1999, the virus had caused encephalitis in Europe, Africa and the Middle East, but had not been identified in the United States. It is commonly carried by birds.

In developing the new test, clinicians analyzed material from 16 patients--half with other forms of encephalitis and half with the West Nile virus, diagnosed by antibody testing.

Lipkin and his colleagues were able to identify the virus in the samples that came from the five patients with the most advanced cases of West Nile encephalitis. Of the five, four had died from the disease and the fifth was a 16-year-old, who recovered. The other three did not develop significant disease symptoms.

“The people who tested positive were the ones who needed treatment,” Lipkin said.

The test uses a polymerase chain reaction, a technique that allows clinicians to take minute quantities of viral fragments and multiply them so they can be identified readily in the lab.

The test would replace a method that takes three to four days and requires sophisticated expertise.

“This is very simple to do,” Lipkin said of the new test. “We have first-year graduate students who can do this one.”