Wednesday, November 16, 2011

Oh Norovirus...

Human norovirus, which belongs to the Caliciviridae family, is the most common cause of acute gastroenteritis, and affects about 1 in 15 Americans each year. According to the CDC, it leads to about 70,000 hospitalizations, and more than 500 deaths annually, and the disease it causes tends to be one of the more unpleasant of those that leave healthy people unscathed in the long run, with diarrhea and vomiting that typically last for 48 hours.
Researchers from Emory University have recently answered a crucial question regarding these dangerous viruses: If well water becomes contaminated with noroviruses, for instance, from leaking sewer lines, then how long would these noroviruses survive in that body of water, and when would it be safe to drink from that well? The answer is least 61 days, and probably far more.

The test they performed consisted of a safety-tested virus stock solution. They placed a known amount of this solution into a container of groundwater and tested the virus's infectivity at various days, starting from 0 and ranging to about 61 days. The volunteers for this study drank from the water and became infected, exhibiting a range of unpleasant symptoms. Unfortunately due to funding issues, the researchers could not conduct the experiment past 61 days, but found that volunteers who had drank the water 61 days after contamination with notovirus still became severely infected. Now you may think that volunteering for such an experiment is quite an odd idea: who would want to experience extreme diarrhea? And possibly even risk being hospitalized? The researchers of this study were actually themselves surprised to see that most volunteers had a desire to test their immunity, and see whether they were actually capable of getting sick..

The important conclusion from the study was that Norovirus may in fact remain infective far longer than 61 days, a significant evidence for the need to treat groundwater used for drinking. The researchers stored the groundwater at room temperature in the dark, and used reverse transcription PCR to calculate how much viral RNA remained after exactly 622 days, and again after 1,266 days. They found no reduction in the amount of viral RNA after the first interval, but saw very little at the end of the second interval.

To read more, here's a good link!

- Julie Saffarian

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