According to the U.S. Department of Health and Human Services/Centers for Disease Control and Prevention (CDC), Chinese authorities identified an outbreak caused by a novel—or new—coronavirus. The virus can cause mild to severe respiratory illness. The outbreak began in Wuhan, Hubei Province, China, and has spread to a growing number of other countries—including the United States. The virus is different from six other, previously identified human coronaviruses, including the Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) coronaviruses that have caused previous respiratory disease outbreaks.
Many of the initial cases identified in Asia were likely the result of exposure in a large seafood and animal market, suggesting a possible zoonotic (i.e., animal) origin to the outbreak. Based on scientific analysis of the virus’ genetic material, some scientists suspect snakes may be the source of the outbreak.
Not all cases are connected to the market, however. The novel coronavirus, COVID-19 has spread directly between people in several countries, including the United States. The Hazard Recognition page describes how COVID-19 is thought to spread.