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Researchers receive patent for virus detection

By Susan Trulove

Spectrum Volume 18 Issue 34 - June 27, 1996

Outbreaks of intestinal diseases due to contaminated water are on the rise world-wide, and more than half of these outbreaks are caused by viruses, according to Charles Hagedorn, Virginia Tech professor of crop and soil environmental sciences.

Marian Ijzerman, a 1994 Ph.D. graduate now with the EPA, along with Hagedorn, her advisor, and biology professor Joe Falkinham, have received a patent (Number 5,527,667 on June 18, 1996) for a "Rapid Virus Detection Technology," which they developed for drinking water, recreational waters, and groundwater.

The test can be used at water-treatment plants and in process water used by food and pharmaceutical industries to let engineers know whether they have to conduct further tests for harmful viruses, Falkinham said.

The test detects the presence or absence of a virus indicator (coliphages). "The rapid virus-detection technology is based on the fact that many viruses cause susceptible cells to break open and release their cellular contents as a consequence of viral infection. Thus, the release of compounds that are normally only found within cells is indicative of the possible presence of a virus," Hagedorn said.

The test detects a specific compound (an enzyme) released from cells in the test medium--"a cellular equivalent of canaries used to detect gas in mines," Hagedorn said.

Presently, the presence of the bacterium Escherichia coli (E. coli) is used throughout the world as an indicator of human fecal contamination of water. If viruses able to infect E. coli are present in a water sample, then its host, E. coli, must also be present.

"An advantage of the rapid virus test is that viruses usually live longer in water samples than bacterial cells, thus presence of virus can indicate previous fecal contamination of water after living cells have died," Falkinham said. Further, the bacterial viruses act more like other viruses, such as the ones that cause human diarrheal infections, than do cells of E. coli, he said. "Numbers of E. coli viruses may be better indicators of human health risk of drinking and recreational waters than numbers of bacteria."

The enzyme-based test is easy, inexpensive, and highly sensitive. The test can detect as few as two viruses in a sample and, because of the specificity of viruses for hosts, the test is quite specific, Hagedorn said. "Because of the simplicity and speed of the test, large numbers of samples can be tested in parallel. Thus, the test can be used to screen large numbers of samples and virus-containing samples can be tested further."

Funding for patent application and commercial development was provided by Virginia's Center for Innovative Technology and Dominion Biosciences Inc.

A description of the development of the rapid virus test was presented at the American Society for Microbiology meeting in May 1995.