Trial flu, Ebola drug shows promise against norovirus

Date: Oct-23-2014 Speeding up mutation is emerging as a potential new way to treat virus

infection. Now, a new study shows that favipiravir - a trial drug currently being tested

against Ebola and influenza - successfully treated norovirus in mice using that

method.

Norovirus, also known as "winter vomiting bug" or "stomach flu," is the most common

cause of acute gastroenteritis in the US.

Norovirus, also known as "winter vomiting bug" or "stomach flu," is the most common

cause of acute gastroenteritis in the US, where every year it causes 19-21 million

illnesses and contributes to 56-71,000 hospitalizations and 570-800 deaths. The

virus is also responsible for most foodborne-disease outbreaks in the US.

Norovirus is extremely contagious; you can get it from contaminated food or water,

an infected person or by touching contaminated surfaces. The virus causes acute

gastroenteritis, where the stomach or intestines - or both - get inflamed, leading to

symptoms such as stomach pain, nausea, diarrhea and vomiting.

Most people who become infected experience an unpleasant but short-lived illness,

but people with weak immune systems can become chronically infected for years and

experience major health problems. Currently, there is no vaccine or treatment for

norovirus.

Norovirus is difficult to study because it does not grow efficiently in the

laboratory. The virus belongs to a class known as RNA viruses because their genetic

material is made of ribonucleic acid (RNA). Most viruses that cause epidemics are RNA

viruses, including Ebola, influenza, SARS and polio.

RNA viruses are a challenge for vaccine and treatment developers because they mutate

and replicate rapidly.

Now, in a new study published in the journal eLife, a team at Cambridge

University in the UK has shown that the experimental broad-range antiviral favipiravir,

currently being trialled for influenza and Ebola viruses, effectively reduced - and in

some cases eliminated - norovirus in mice.

Their work shows that favipiravir is effective at reducing norovirus in the body

and in feces, which may help reduce disease severity and onward transmission.

Favipiravir can make norovirus 'mutate itself to death'

In their study, the team shows how by speeding up mutation in the virus, the drug

induces errors to develop in the viral genetic code. And, since the virus also

replicates rapidly, these errors quickly accumulate and take hold, eventually preventing

further replication and spread.

Dr. Armando Arias, a researcher in the lab of Ian Goodfellow, senior author and

professor in the department of pathology at Cambridge, says:

"Our work in mice is very promising and shows that the drug favipiravir can make the

virus mutate itself to death."

The authors say this is the first time someone has shown you can fight a virus by

making it mutate itself to death in the host. They suggest it may be possible to fight

other RNA viruses in the same way.

Professor Goodfellow, a Wellcome Trust senior fellow, says most people will have been

infected with norovirus at some point and experienced it as an unpleasant but mild

illness that can be treated by drinking plenty of fluids and riding it out.

"But some patients get infections that can last months or years, and this has a real

impact on their quality of life," he adds. "The ease with which infections spread, particularly in

places such as hospitals, schools and cruise ships, and the potentially serious health

problems norovirus can cause people with weakened immune systems means that we

desperately need a way to treat infection."

Dr. Arias says as well as treating infected individuals, "the drug may also be useful

in preventing infection during an outbreak. The next steps will be to test whether this

drug is safe and effective at treating patients, too."

The study was funded by the Wellcome Trust.

In June 2014, Medical News Today reported how, after conducting the largest

ever review of noroviruses and acute gastroenteritis, the Centers for Disease Control

and Prevention (CDC) found estimates are higher than previously thought, highlighting

the need for norovirus vaccines.

Written by Catharine Paddock PhD

Not to be reproduced without permission.

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Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.