The coronavirus outbreak has sickened more than 101,700 people. At least 3,453 people have died, all but 411 in mainland China. As the map below shows, the disease has been detected in at least 83 countries.

Sustained local transmission of the virus has been reported in South Korea, Japan, Italy, and Iran, raising fears of a global pandemic. The C.D.C. has advised against all non-essential travel to South Korea, China, Italy, and Iran. The number of known coronavirus cases in the United States continues to grow quickly. As of Friday afternoon, there have been at least 283 cases of coronavirus confirmed by lab tests and 14 deaths, according to a New York Times database.
Many of the people infected in the United States are former passengers of the Diamond Princess cruise ship who are currently in quarantine on military bases or in hospitals.

Many of the cases across Europe have been traced back to Italy, which has one of the world’s largest outbreaks. At least 4,636 people have tested positive.

While the outbreak is a serious public health concern, most people who contract the coronavirus do not become seriously ill, and only a small percentage require intensive care. Older people and those with existing health conditions, like heart disease or diabetes, are at higher risk.