Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New UNC experiments show very weak chlorine solutions can kill noroviruses


Chlorine solutions much weaker than previously believed can still be used to kill more than 99 percent of noroviruses, the chief cause of outbreaks of gastrointestinal illness around the world, a new University of North Carolina at Chapel Hill study concludes.

Researchers presented their findings over the weekend at the 2005 International Conference on Antimicrobial Agents and Chemotherapy, which ends today (Dec. 19) in Washington, D.C. They discovered for the first time that dilute solutions of hypochlorous acid, or free chlorine, as low as 200 -- or even 20 -- milligrams per liter will completely inactivate noroviruses on surfaces such as stainless steel and ceramic tile.

Dr. Mark D. Sobsey, professor of environmental sciences and engineering at the UNC School of Public Health, and postdoctoral fellow Dr. Geunwoo Park conducted the research. They also found that the dilute chemical worked quickly -- in five minutes or less.

“This is good news since noroviruses are the leading cause of viral gastroenteritis,” said Sobsey, director of the school’s Environmental Health Microbiology Laboratories. “They have caused countless outbreaks of gastroenteritis in health-care facilities, schools, food establishments, hotels and resorts and on cruise ships.”

Decontamination of affected facilities can prove difficult since the viruses persist on environmental surfaces and are resistant to some widely used sanitizers, he said. And they are highly infectious even at low doses.

In their studies, the scientists dried a group II norovirus -- the predominant form circulating in the USA -- and a widely used indicator virus, bacteriophage MS2 infecting E. coli, on stainless steel and ceramic surfaces, Sobsey said. After treating those surfaces with a 200 milligrams per liter solution of hypochlorous acid for one minute, they tested them to learn how much virus remained. The viruses dropped 99.99 percent.

“Even a lower concentration of 20 milligrams per liter of hypochlorous acid reduced the viruses by 99.9 percent in five minutes,” he said. “Our results show that environmental surfaces can be readily decontaminated of noroviruses with dilute hypochlorous acid, which is the active ingredient of household bleaches like Chlorox.”

In practical terms, that means that household bleach can be diluted by a factor of 1,000 and still work, Sobsey said. In all likelihood, it would even disinfect noroviruses on hard surfaces if diluted by a factor of 10,000. At full strength, the bleach contains 50,000 to 60,000 milligrams per liter of chlorine.

“Previously, many people have diluted household bleach to one part in 10, which is still a strongly corrosive solution,” he said. “They often are reluctant to use at that strength since it can mar surfaces and make them look bad.”

Regularly disinfecting bathrooms, kitchens and other areas prone to harbor viruses and bacteria is important because outbreaks of gastrointestinal illness, which include nausea, vomiting and diarrhea, can kill people, especially if they are old or dehydrated, Sobsey said. While most otherwise healthy patients recover after a few days of discomfort even without treatment, noroviruses can continue to sicken others until facilities have been thoroughly sanitized with products proven to be effective.

In the research, Sobsey and Park generated hypochlorous acid from a dilute solution of salt using an electrolytic generator made by Sterilox Technologies. That company, which supported the research, manufactures on-site generators of room-temperature, high-level hypochlorous acid disinfectant for use in biomedical, food production, water treatment and other applications.

David Williamson | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>