( CNN ) MERS-CoV , short for Middle East Respiratory Syndrome coronavirus , first surfaced in Saudi Arabia in spring 2012 . As of June 8 , more than 1,000 cases of MERS have been confirmed in 25 countries , according to the World Health Organization . Two of those cases were in the United States . There have been over 400 deaths worldwide . Here are five things you should know about MERS : . It 's a coronavirus . MERS is in the same family of viruses as SARS ( severe acute respiratory syndrome -- coronavirus ) as well as the common cold . However , unlike SARS , which sickened more than 8,000 people in 2003 and killed 773 worldwide , MERS does not spread easily between humans -- at least not yet . The virus acts like a cold and attacks the respiratory system , the Centers for Disease Control and Prevention has said . But symptoms , which include fever and a cough , are severe and can lead to pneumonia and kidney failure . Gastrointestinal symptoms such as diarrhea have also been seen , according to the WHO . The average age of MERS victims is 51 , officials say , although the ages range from 2 to 94 . Researchers do n't know how MERS spreads . Although all MERS cases have been linked to six countries on the Arabian Peninsula , limited human-to-human transmission has been seen among people in close contact with patients , including health care workers . Although such transmission appears to be limited , health officials are concerned about MERS because of its virulence -- it can be fatal in up to one-third of cases , Dr. Anne Schuchat , assistant surgeon general for the U.S. Public Health Service and director of the National Center for Immunization and Respiratory Diseases , said Friday . `` The virus has not shown to spread in a sustained way in communities , '' the CDC says on its website . The WHO and CDC have not issued any travel warnings related to MERS , although the CDC suggests travelers to the Arabian Peninsula practice `` enhanced precautions . '' And `` you are not considered to be at risk for MERS-CoV infection if you have not had close contact , such as caring for or living with someone who is being evaluated for MERS-CoV infection , '' according to the CDC website . Camels appear to be a link in the MERS chain . Camels may be one clue . In a paper published earlier this week , researchers said they had isolated the live MERS virus from two single-humped camels , known as dromedaries . And in February , scientists published a finding that nearly three-quarters of camels in Saudi Arabia tested positive for past MERS exposure . MERS was also found in a bat in Saudi Arabia , the CDC says . `` The way humans become infected from an animal and/or environmental source is still under investigation , '' the WHO said last month . It may have a seasonal pattern . Officials have noted a surge in MERS cases this spring , and a similar increase was also seen last spring , Schuchat said on Friday . But they do n't know whether the factors that lead to MERS may have a seasonal pattern , or whether the virus changes to become more easily transmissible . There are no treatments and no vaccine . As of now , doctors can treat symptoms of MERS , such as fever or breathing difficulties , Schuchat said . However , there is no vaccine and no specific medicine , such as an antiviral drug , that targets MERS .
MERS has shown limited human-to-human transmission . The WHO said it was working with the World Health Organization and other partners to investigate whether there is a link between MERS-CoV and any of its known cases. There is no treatment and no vaccine .