Ask any person on the street about coronaviruses, and the chances will be pretty good that they don’t know what you’re talking about. However, chances are also pretty good that they’ll have had one before, as coronaviruses are one of the leading causes of the common cold, and our pets are often vaccinated against them. Though colds aren’t something to be too concerned about, other coronaviruses can be much worse. This includes the severe acute respiratory syndrome, or SARS, outbreak in 2003, as well as a newly discovered coronavirus that was discovered in 15 patients in the Middle East last September and has killed more than half of them.

Coronaviruses are named such because of a little “halo” of proteins that are embedded in the protective envelope of a virus. These proteins help the virus bind to specific host cells, and they generally infect the respiratory tracts of humans as well as farm animals and pets. The 2003 SARS outbreak, which started in Hong Kong, originally spread from civet cats and eventually infected more than 8,000 people in more than 30 countries. Bats are also a common host, and scientists speculate that they may be the source of the new coronavirus, but one victim claimed to have gotten it after his goats were sick, and others claimed no exposure to any animals at all.

Cases of the new coronavirus were almost exclusively in the Middle East, including patients in Saudi Arabia, Qatar, Jordan, and a UK patient who visited Mecca. Studies thus far have shown no sign that it is easily transmissible, as hospital workers who have treated the patients haven’t contracted it. Viruses’ high mutation rate could very quickly change that if the mutation produced a virulent strain. Continued testing and tracking of the virus and its hosts, with the knowledge of coronaviruses gained from SARS, could give doctors the edge in case of another outbreak.