Researchers have revealed a new promising drug that can act as a broad-spectrum antiviral which can inhibit strains of SARS, MERS, Ebola infection, as well MHV, which is closely-related to several human coronaviruses that can cause respiratory tract infections.

Researchers have long known that RNA viruses called coronaviruses cause common cold and pneumonia. In the last two decades or so, though, researchers have found that these viruses can jump between animal and human hosts. In recent years, coronaviruses have caused lethal outbreaks of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) that span multiple continents. To date, no retroviral drug has been approved to treat these infections.

“These viruses are poised to cause outbreaks,” says molecular virologist Ralph C. Baric at the University of North Carolina at Chapel Hill, “and most emerging viruses are cyclic in nature.” In the case of SARS, the coronavirus caused an outbreak that began in 2003 and was eventually controlled through public health efforts. However, many pre-epidemic forms of the virus are still around. “We need to have broad-based and potent drugs on a shelf to control future epidemics.”

This week in mBio, researchers report on GS-5734, a promising experimental broad-spectrum antiviral drug. Previous studies have shown that the drug inhibits strains of SARS and MERS coronaviruses that infect human airways and the lower respiratory tract, as well as infection by the Ebola virus. The researchers now report that the drug also inhibits murine hepatitis virus, or MHV, which is closely related to several human coronaviruses that can cause respiratory tract infections, sometimes as severe as SARS.