Coronaviruses are types of viruses that typically affect the respiratory tracts of birds and mammals, including humans. Doctors associate them with the common cold, bronchitis, pneumonia, and severe acute respiratory syndrome (SARS), and they can also affect the gut.
These viruses are typically responsible for common colds more than serious diseases. However, coronaviruses are also behind some more severe outbreaks. 
Over the last 70 years, scientists have found that coronaviruses can infect mice, rats, dogs, cats, turkeys, horses, pigs, and cattle. Sometimes, these animals can transmit coronaviruses to humans.